class Sequel::Database

A Database object represents a virtual connection to a database. The Database class is meant to be subclassed by database adapters in order to provide the functionality needed for executing queries.

1 - Methods that execute queries and/or return results

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Constants

COLUMN_SCHEMA_DATETIME_TYPES
COLUMN_SCHEMA_STRING_TYPES
CURRENT_TIMESTAMP_RE
STRING_DEFAULT_RE

Attributes

cache_schema[RW]

Whether the schema should be cached for this database. True by default for performance, can be set to false to always issue a database query to get the schema.

prepared_statements[R]

The prepared statement object hash for this database, keyed by name symbol

Public Instance Methods

<<(sql) click to toggle source

Runs the supplied SQL statement string on the database server. Returns self so it can be safely chained:

DB << "UPDATE albums SET artist_id = NULL" << "DROP TABLE artists"
# File lib/sequel/database/query.rb, line 27
def <<(sql)
  run(sql)
  self
end
call(ps_name, hash={}, &block) click to toggle source

Call the prepared statement with the given name with the given hash of arguments.

DB[:items].where(:id=>1).prepare(:first, :sa)
DB.call(:sa) # SELECT * FROM items WHERE id = 1
# File lib/sequel/database/query.rb, line 37
def call(ps_name, hash={}, &block)
  prepared_statement(ps_name).call(hash, &block)
end
execute_ddl(sql, opts=OPTS, &block) click to toggle source

Method that should be used when submitting any DDL (Data Definition Language) SQL, such as create_table. By default, calls execute_dui. This method should not be called directly by user code.

# File lib/sequel/database/query.rb, line 44
def execute_ddl(sql, opts=OPTS, &block)
  execute_dui(sql, opts, &block)
end
execute_dui(sql, opts=OPTS, &block) click to toggle source

Method that should be used when issuing a DELETE, UPDATE, or INSERT statement. By default, calls execute. This method should not be called directly by user code.

# File lib/sequel/database/query.rb, line 51
def execute_dui(sql, opts=OPTS, &block)
  execute(sql, opts, &block)
end
execute_insert(sql, opts=OPTS, &block) click to toggle source

Method that should be used when issuing a INSERT statement. By default, calls execute_dui. This method should not be called directly by user code.

# File lib/sequel/database/query.rb, line 58
def execute_insert(sql, opts=OPTS, &block)
  execute_dui(sql, opts, &block)
end
get(*args, &block) click to toggle source

Returns a single value from the database, e.g.:

DB.get(1) # SELECT 1
# => 1
DB.get{server_version{}} # SELECT server_version()
# File lib/sequel/database/query.rb, line 67
def get(*args, &block)
  @default_dataset.get(*args, &block)
end
run(sql, opts=OPTS) click to toggle source

Runs the supplied SQL statement string on the database server. Returns nil. Options:

:server

The server to run the SQL on.

DB.run("SET some_server_variable = 42")
# File lib/sequel/database/query.rb, line 76
def run(sql, opts=OPTS)
  sql = literal(sql) if sql.is_a?(SQL::PlaceholderLiteralString)
  execute_ddl(sql, opts)
  nil
end
schema(table, opts=OPTS) click to toggle source

Returns the schema for the given table as an array with all members being arrays of length 2, the first member being the column name, and the second member being a hash of column information. The table argument can also be a dataset, as long as it only has one table. Available options are:

:reload

Ignore any cached results, and get fresh information from the database.

:schema

An explicit schema to use. It may also be implicitly provided via the table name.

If schema parsing is supported by the database, the column information hash should contain at least the following entries:

:allow_null

Whether NULL is an allowed value for the column.

:db_type

The database type for the column, as a database specific string.

:default

The database default for the column, as a database specific string, or nil if there is no default value.

:primary_key

Whether the columns is a primary key column. If this column is not present, it means that primary key information is unavailable, not that the column is not a primary key.

:ruby_default

The database default for the column, as a ruby object. In many cases, complex database defaults cannot be parsed into ruby objects, in which case nil will be used as the value.

:type

A symbol specifying the type, such as :integer or :string.

Example:

DB.schema(:artists)
# [[:id,
#   {:type=>:integer,
#    :primary_key=>true,
#    :default=>"nextval('artist_id_seq'::regclass)",
#    :ruby_default=>nil,
#    :db_type=>"integer",
#    :allow_null=>false}],
#  [:name,
#   {:type=>:string,
#    :primary_key=>false,
#    :default=>nil,
#    :ruby_default=>nil,
#    :db_type=>"text",
#    :allow_null=>false}]]
# File lib/sequel/database/query.rb, line 123
def schema(table, opts=OPTS)
  raise(Error, 'schema parsing is not implemented on this database') unless supports_schema_parsing?

  opts = opts.dup
  tab = if table.is_a?(Dataset)
    o = table.opts
    from = o[:from]
    raise(Error, "can only parse the schema for a dataset with a single from table") unless from && from.length == 1 && !o.include?(:join) && !o.include?(:sql)
    table.first_source_table
  else
    table
  end

  qualifiers = split_qualifiers(tab)
  table_name = qualifiers.pop
  sch = qualifiers.pop
  information_schema_schema = case qualifiers.length
  when 1
    Sequel.identifier(*qualifiers)
  when 2
    Sequel.qualify(*qualifiers)
  end

  if table.is_a?(Dataset)
    quoted_name = table.literal(tab)
    opts[:dataset] = table
  else
    quoted_name = schema_utility_dataset.literal(table)
  end

  opts[:schema] = sch if sch && !opts.include?(:schema)
  opts[:information_schema_schema] = information_schema_schema if information_schema_schema && !opts.include?(:information_schema_schema)

  Sequel.synchronize{@schemas.delete(quoted_name)} if opts[:reload]
  if v = Sequel.synchronize{@schemas[quoted_name]}
    return v
  end

  cols = schema_parse_table(table_name, opts)
  raise(Error, "schema parsing returned no columns, table #{table_name.inspect} probably doesn't exist") if cols.nil? || cols.empty?

  primary_keys = 0
  auto_increment_set = false
  cols.each do |_,c|
    auto_increment_set = true if c.has_key?(:auto_increment)
    primary_keys += 1 if c[:primary_key]
  end

  cols.each do |_,c|
    c[:ruby_default] = column_schema_to_ruby_default(c[:default], c[:type]) unless c.has_key?(:ruby_default)
    if c[:primary_key] && !auto_increment_set
      # If adapter didn't set it, assume that integer primary keys are auto incrementing
      c[:auto_increment] = primary_keys == 1 && !!(c[:db_type] =~ /int/io)
    end
    if !c[:max_length] && c[:type] == :string && (max_length = column_schema_max_length(c[:db_type]))
      c[:max_length] = max_length
    end
  end
  Sequel.synchronize{@schemas[quoted_name] = cols} if cache_schema
  cols
end
table_exists?(name) click to toggle source

Returns true if a table with the given name exists. This requires a query to the database.

DB.table_exists?(:foo) # => false
# SELECT NULL FROM foo LIMIT 1

Note that since this does a SELECT from the table, it can give false negatives if you don't have permission to SELECT from the table.

# File lib/sequel/database/query.rb, line 193
def table_exists?(name)
  sch, table_name = schema_and_table(name)
  name = SQL::QualifiedIdentifier.new(sch, table_name) if sch
  ds = from(name)
  transaction(:savepoint=>:only){_table_exists?(ds)}
  true
rescue DatabaseError
  false
end

Private Instance Methods

_metadata_dataset() click to toggle source

Uncached version of #metadata_dataset, designed for overriding.

# File lib/sequel/database/query.rb, line 291
def _metadata_dataset
  dataset
end
_table_exists?(ds) click to toggle source

Should raise an error if the table doesn't not exist, and not raise an error if the table does exist.

# File lib/sequel/database/query.rb, line 207
def _table_exists?(ds)
  ds.get(SQL::AliasedExpression.new(Sequel::NULL, :nil))
end
column_schema_default_string_type?(type) click to toggle source

Whether the type should be treated as a string type when parsing the column schema default value.

# File lib/sequel/database/query.rb, line 213
def column_schema_default_string_type?(type)
  COLUMN_SCHEMA_STRING_TYPES.include?(type)
end
column_schema_default_to_ruby_value(default, type) click to toggle source

Transform the given normalized default string into a ruby object for the given type.

# File lib/sequel/database/query.rb, line 219
def column_schema_default_to_ruby_value(default, type)
  case type
  when :boolean
    case default 
    when /[f0]/i
      false
    when /[t1]/i
      true
    end
  when :string, :enum, :set, :interval
    default
  when :blob
    Sequel::SQL::Blob.new(default)
  when :integer
    Integer(default)
  when :float
    Float(default)
  when :date
    Sequel.string_to_date(default)
  when :datetime
    DateTime.parse(default)
  when :time
    Sequel.string_to_time(default)
  when :decimal
    BigDecimal.new(default)
  end
end
column_schema_max_length(db_type) click to toggle source

Look at the db_type and guess the maximum length of the column. This assumes types such as varchar(255).

# File lib/sequel/database/query.rb, line 277
def column_schema_max_length(db_type)
  if db_type =~ /\((\d+)\)/
    $1.to_i
  end
end
column_schema_normalize_default(default, type) click to toggle source

Normalize the default value string for the given type and return the normalized value.

# File lib/sequel/database/query.rb, line 249
def column_schema_normalize_default(default, type)
  if column_schema_default_string_type?(type)
    return unless m = STRING_DEFAULT_RE.match(default)
    m[1].gsub("''", "'")
  else
    default
  end
end
column_schema_to_ruby_default(default, type) click to toggle source

Convert the given default, which should be a database specific string, into a ruby object.

# File lib/sequel/database/query.rb, line 260
def column_schema_to_ruby_default(default, type)
  return default unless default.is_a?(String)
  if COLUMN_SCHEMA_DATETIME_TYPES.include?(type)
    if CURRENT_TIMESTAMP_RE.match(default)
      if type == :date
        return Sequel::CURRENT_DATE
      else
        return Sequel::CURRENT_TIMESTAMP
      end
    end
  end
  default = column_schema_normalize_default(default, type)
  column_schema_default_to_ruby_value(default, type) rescue nil
end
input_identifier_meth(ds=nil) click to toggle source

Return a Method object for the dataset's output_identifier_method. Used in metadata parsing to make sure the returned information is in the correct format.

# File lib/sequel/database/query.rb, line 286
def input_identifier_meth(ds=nil)
  (ds || dataset).method(:input_identifier)
end
metadata_dataset() click to toggle source

Return a dataset that uses the default identifier input and output methods for this database. Used when parsing metadata so that column symbols are returned as expected.

# File lib/sequel/database/query.rb, line 298
def metadata_dataset
  @metadata_dataset ||= _metadata_dataset
end
output_identifier_meth(ds=nil) click to toggle source

Return a Method object for the dataset's output_identifier_method. Used in metadata parsing to make sure the returned information is in the correct format.

# File lib/sequel/database/query.rb, line 305
def output_identifier_meth(ds=nil)
  (ds || dataset).method(:output_identifier)
end
remove_cached_schema(table) click to toggle source

Remove the cached schema for the given schema name

# File lib/sequel/database/query.rb, line 310
def remove_cached_schema(table)
  k = quote_schema_table(table)
  Sequel.synchronize{@schemas.delete(k)}
end
schema_column_type(db_type) click to toggle source

Match the database's column type to a ruby type via a regular expression, and return the ruby type as a symbol such as :integer or :string.

# File lib/sequel/database/query.rb, line 318
def schema_column_type(db_type)
  case db_type
  when /\A(character( varying)?|n?(var)?char|n?text|string|clob)/io
    :string
  when /\A(int(eger)?|(big|small|tiny)int)/io
    :integer
  when /\Adate\z/io
    :date
  when /\A((small)?datetime|timestamp( with(out)? time zone)?)(\(\d+\))?\z/io
    :datetime
  when /\Atime( with(out)? time zone)?\z/io
    :time
  when /\A(bool(ean)?)\z/io
    :boolean
  when /\A(real|float|double( precision)?|double\(\d+,\d+\)( unsigned)?)\z/io
    :float
  when /\A(?:(?:(?:num(?:ber|eric)?|decimal)(?:\(\d+,\s*(\d+|false|true)\))?))\z/io
    $1 && ['0', 'false'].include?($1) ? :integer : :decimal
  when /bytea|blob|image|(var)?binary/io
    :blob
  when /\Aenum/io
    :enum
  end
end

2 - Methods that modify the database schema

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Constants

AUTOINCREMENT
COLUMN_DEFINITION_ORDER

The order of column modifiers to use when defining a column.

COMBINABLE_ALTER_TABLE_OPS

The alter table operations that are combinable.

COMMA_SEPARATOR
DEFAULT_JOIN_TABLE_COLUMN_OPTIONS

The default options for join table columns.

NOT_NULL
NULL
PRIMARY_KEY
TEMPORARY
UNDERSCORE
UNIQUE
UNSIGNED

Public Instance Methods

add_column(table, *args) click to toggle source

Adds a column to the specified table. This method expects a column name, a datatype and optionally a hash with additional constraints and options:

DB.add_column :items, :name, :text, :unique => true, :null => false
DB.add_column :items, :category, :text, :default => 'ruby'

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 38
def add_column(table, *args)
  alter_table(table) {add_column(*args)}
end
add_index(table, columns, options=OPTS) click to toggle source

Adds an index to a table for the given columns:

DB.add_index :posts, :title
DB.add_index :posts, [:author, :title], :unique => true

Options:

:ignore_errors

Ignore any DatabaseErrors that are raised

:name

Name to use for index instead of default

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 52
def add_index(table, columns, options=OPTS)
  e = options[:ignore_errors]
  begin
    alter_table(table){add_index(columns, options)}
  rescue DatabaseError
    raise unless e
  end
end
alter_table(name, generator=nil, &block) click to toggle source

Alters the given table with the specified block. Example:

DB.alter_table :items do
  add_column :category, :text, :default => 'ruby'
  drop_column :category
  rename_column :cntr, :counter
  set_column_type :value, :float
  set_column_default :value, :float
  add_index [:group, :category]
  drop_index [:group, :category]
end

Note that add_column accepts all the options available for column definitions using create_table, and add_index accepts all the options available for index definition.

See Schema::AlterTableGenerator and the “Migrations and Schema Modification” guide.

# File lib/sequel/database/schema_methods.rb, line 78
def alter_table(name, generator=nil, &block)
  generator ||= alter_table_generator(&block)
  remove_cached_schema(name)
  apply_alter_table_generator(name, generator)
  nil
end
alter_table_generator(&block) click to toggle source

Return a new Schema::AlterTableGenerator instance with the receiver as the database and the given block.

# File lib/sequel/database/schema_methods.rb, line 87
def alter_table_generator(&block)
  alter_table_generator_class.new(self, &block)
end
create_join_table(hash, options=OPTS) click to toggle source

Create a join table using a hash of foreign keys to referenced table names. Example:

create_join_table(:cat_id=>:cats, :dog_id=>:dogs)
# CREATE TABLE cats_dogs (
#  cat_id integer NOT NULL REFERENCES cats,
#  dog_id integer NOT NULL REFERENCES dogs,
#  PRIMARY KEY (cat_id, dog_id)
# )
# CREATE INDEX cats_dogs_dog_id_cat_id_index ON cats_dogs(dog_id, cat_id)

The primary key and index are used so that almost all operations on the table can benefit from one of the two indexes, and the primary key ensures that entries in the table are unique, which is the typical desire for a join table.

You can provide column options by making the values in the hash be option hashes, so long as the option hashes have a :table entry giving the table referenced:

create_join_table(:cat_id=>{:table=>:cats, :type=>:Bignum}, :dog_id=>:dogs)

You can provide a second argument which is a table options hash:

create_join_table({:cat_id=>:cats, :dog_id=>:dogs}, :temp=>true)

Some table options are handled specially:

:index_options

The options to pass to the index

:name

The name of the table to create

:no_index

Set to true not to create the second index.

:no_primary_key

Set to true to not create the primary key.

# File lib/sequel/database/schema_methods.rb, line 123
def create_join_table(hash, options=OPTS)
  keys = hash.keys.sort_by(&:to_s)
  create_table(join_table_name(hash, options), options) do
    keys.each do |key|
      v = hash[key]
      unless v.is_a?(Hash)
        v = {:table=>v}
      end
      v = DEFAULT_JOIN_TABLE_COLUMN_OPTIONS.merge(v)
      foreign_key(key, v)
    end
    primary_key(keys) unless options[:no_primary_key]
    index(keys.reverse, options[:index_options] || {}) unless options[:no_index]
  end
end
create_join_table!(hash, options=OPTS) click to toggle source

Forcibly create a join table, attempting to drop it if it already exists, then creating it.

# File lib/sequel/database/schema_methods.rb, line 140
def create_join_table!(hash, options=OPTS)
  drop_table?(join_table_name(hash, options))
  create_join_table(hash, options)
end
create_join_table?(hash, options=OPTS) click to toggle source

Creates the join table unless it already exists.

# File lib/sequel/database/schema_methods.rb, line 146
def create_join_table?(hash, options=OPTS)
  if supports_create_table_if_not_exists? && options[:no_index]
    create_join_table(hash, options.merge(:if_not_exists=>true))
  elsif !table_exists?(join_table_name(hash, options))
    create_join_table(hash, options)
  end
end
create_or_replace_view(name, source, options = OPTS) click to toggle source

Creates a view, replacing a view with the same name if one already exists.

DB.create_or_replace_view(:some_items, "SELECT * FROM items WHERE price < 100")
DB.create_or_replace_view(:some_items, DB[:items].where(:category => 'ruby'))

For databases where replacing a view is not natively supported, support is emulated by dropping a view with the same name before creating the view.

# File lib/sequel/database/schema_methods.rb, line 242
def create_or_replace_view(name, source, options = OPTS)
  if supports_create_or_replace_view?
    options = options.merge(:replace=>true)
  else
    drop_view(name) rescue nil
  end

  create_view(name, source, options)
end
create_table(name, options=OPTS, &block) click to toggle source

Creates a table with the columns given in the provided block:

DB.create_table :posts do
  primary_key :id
  column :title, :text
  String :content
  index :title
end

General options:

:as

Create the table using the value, which should be either a dataset or a literal SQL string. If this option is used, a block should not be given to the method.

:ignore_index_errors

Ignore any errors when creating indexes.

:temp

Create the table as a temporary table.

MySQL specific options:

:charset

The character set to use for the table.

:collate

The collation to use for the table.

:engine

The table engine to use for the table.

PostgreSQL specific options:

:on_commit

Either :preserve_rows (default), :drop or :delete_rows. Should only be specified when creating a temporary table.

:foreign

Create a foreign table. The value should be the name of the foreign server that was specified in CREATE SERVER.

:inherits

Inherit from a different table. An array can be specified to inherit from multiple tables.

:unlogged

Create the table as an unlogged table.

:options

The OPTIONS clause to use for foreign tables. Should be a hash where keys are option names and values are option values. Note that option names are unquoted, so you should not use untrusted keys.

See Schema::Generator and the “Schema Modification” guide.

# File lib/sequel/database/schema_methods.rb, line 189
def create_table(name, options=OPTS, &block)
  remove_cached_schema(name)
  options = {:generator=>options} if options.is_a?(Schema::CreateTableGenerator)
  if sql = options[:as]
    raise(Error, "can't provide both :as option and block to create_table") if block
    create_table_as(name, sql, options)
  else
    generator = options[:generator] || create_table_generator(&block)
    create_table_from_generator(name, generator, options)
    create_table_indexes_from_generator(name, generator, options)
    nil
  end
end
create_table!(name, options=OPTS, &block) click to toggle source

Forcibly create a table, attempting to drop it if it already exists, then creating it.

DB.create_table!(:a){Integer :a} 
# SELECT NULL FROM a LIMIT 1 -- check existence
# DROP TABLE a -- drop table if already exists
# CREATE TABLE a (a integer)
# File lib/sequel/database/schema_methods.rb, line 209
def create_table!(name, options=OPTS, &block)
  drop_table?(name)
  create_table(name, options, &block)
end
create_table?(name, options=OPTS, &block) click to toggle source

Creates the table unless the table already exists.

DB.create_table?(:a){Integer :a} 
# SELECT NULL FROM a LIMIT 1 -- check existence
# CREATE TABLE a (a integer) -- if it doesn't already exist
# File lib/sequel/database/schema_methods.rb, line 219
def create_table?(name, options=OPTS, &block)
  options = options.dup
  generator = options[:generator] ||= create_table_generator(&block)
  if generator.indexes.empty? && supports_create_table_if_not_exists?
    create_table(name, options.merge!(:if_not_exists=>true))
  elsif !table_exists?(name)
    create_table(name, options)
  end
end
create_table_generator(&block) click to toggle source

Return a new Schema::CreateTableGenerator instance with the receiver as the database and the given block.

# File lib/sequel/database/schema_methods.rb, line 231
def create_table_generator(&block)
  create_table_generator_class.new(self, &block)
end
create_view(name, source, options = OPTS) click to toggle source

Creates a view based on a dataset or an SQL string:

DB.create_view(:cheap_items, "SELECT * FROM items WHERE price < 100")
# CREATE VIEW cheap_items AS
# SELECT * FROM items WHERE price < 100

DB.create_view(:ruby_items, DB[:items].where(:category => 'ruby'))
# CREATE VIEW ruby_items AS
# SELECT * FROM items WHERE (category = 'ruby')

DB.create_view(:checked_items, DB[:items].where(:foo), :check=>true)
# CREATE VIEW checked_items AS
# SELECT * FROM items WHERE foo
# WITH CHECK OPTION

Options:

:columns

The column names to use for the view. If not given, automatically determined based on the input dataset.

:check

Adds a WITH CHECK OPTION clause, so that attempting to modify rows in the underlying table that would not be returned by the view is not allowed. This can be set to :local to use WITH LOCAL CHECK OPTION.

PostgreSQL/SQLite specific option:

:temp

Create a temporary view, automatically dropped on disconnect.

PostgreSQL specific options:

:materialized

Creates a materialized view, similar to a regular view, but backed by a physical table.

:recursive

Creates a recursive view. As columns must be specified for recursive views, you can also set them as the value of this option. Since a recursive view requires a union that isn't in a subquery, if you are providing a Dataset as the source argument, if should probably call the union method with the :all=>true and :from_self=>false options.

# File lib/sequel/database/schema_methods.rb, line 287
def create_view(name, source, options = OPTS)
  execute_ddl(create_view_sql(name, source, options))
  remove_cached_schema(name)
  nil
end
drop_column(table, *args) click to toggle source

Removes a column from the specified table:

DB.drop_column :items, :category

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 298
def drop_column(table, *args)
  alter_table(table) {drop_column(*args)}
end
drop_index(table, columns, options=OPTS) click to toggle source

Removes an index for the given table and column/s:

DB.drop_index :posts, :title
DB.drop_index :posts, [:author, :title]

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 308
def drop_index(table, columns, options=OPTS)
  alter_table(table){drop_index(columns, options)}
end
drop_join_table(hash, options=OPTS) click to toggle source

Drop the join table that would have been created with the same arguments to #create_join_table:

drop_join_table(:cat_id=>:cats, :dog_id=>:dogs)
# DROP TABLE cats_dogs
# File lib/sequel/database/schema_methods.rb, line 317
def drop_join_table(hash, options=OPTS)
  drop_table(join_table_name(hash, options), options)
end
drop_table(*names) click to toggle source

Drops one or more tables corresponding to the given names:

DB.drop_table(:posts) # DROP TABLE posts
DB.drop_table(:posts, :comments)
DB.drop_table(:posts, :comments, :cascade=>true)
# File lib/sequel/database/schema_methods.rb, line 326
def drop_table(*names)
  options = names.last.is_a?(Hash) ? names.pop : {}
  names.each do |n|
    execute_ddl(drop_table_sql(n, options))
    remove_cached_schema(n)
  end
  nil
end
drop_table?(*names) click to toggle source

Drops the table if it already exists. If it doesn't exist, does nothing.

DB.drop_table?(:a)
# SELECT NULL FROM a LIMIT 1 -- check existence
# DROP TABLE a -- if it already exists
# File lib/sequel/database/schema_methods.rb, line 341
def drop_table?(*names)
  options = names.last.is_a?(Hash) ? names.pop : {}
  if supports_drop_table_if_exists?
    options = options.merge(:if_exists=>true)
    names.each do |name|
      drop_table(name, options)
    end
  else
    names.each do |name|
      drop_table(name, options) if table_exists?(name)
    end
  end
end
drop_view(*names) click to toggle source

Drops one or more views corresponding to the given names:

DB.drop_view(:cheap_items)
DB.drop_view(:cheap_items, :pricey_items)
DB.drop_view(:cheap_items, :pricey_items, :cascade=>true)
DB.drop_view(:cheap_items, :pricey_items, :if_exists=>true)

Options:

:cascade

Also drop objects depending on this view.

:if_exists

Do not raise an error if the view does not exist.

PostgreSQL specific options:

:materialized

Drop a materialized view.

# File lib/sequel/database/schema_methods.rb, line 368
def drop_view(*names)
  options = names.last.is_a?(Hash) ? names.pop : {}
  names.each do |n|
    execute_ddl(drop_view_sql(n, options))
    remove_cached_schema(n)
  end
  nil
end
rename_column(table, *args) click to toggle source

Renames a column in the specified table. This method expects the current column name and the new column name:

DB.rename_column :items, :cntr, :counter

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 394
def rename_column(table, *args)
  alter_table(table) {rename_column(*args)}
end
rename_table(name, new_name) click to toggle source

Renames a table:

DB.tables #=> [:items]
DB.rename_table :items, :old_items
DB.tables #=> [:old_items]
# File lib/sequel/database/schema_methods.rb, line 382
def rename_table(name, new_name)
  execute_ddl(rename_table_sql(name, new_name))
  remove_cached_schema(name)
  nil
end
set_column_default(table, *args) click to toggle source

Sets the default value for the given column in the given table:

DB.set_column_default :items, :category, 'perl!'

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 403
def set_column_default(table, *args)
  alter_table(table) {set_column_default(*args)}
end
set_column_type(table, *args) click to toggle source

Set the data type for the given column in the given table:

DB.set_column_type :items, :price, :float

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 412
def set_column_type(table, *args)
  alter_table(table) {set_column_type(*args)}
end

Private Instance Methods

alter_table_add_column_sql(table, op) click to toggle source
# File lib/sequel/database/schema_methods.rb, line 451
def alter_table_add_column_sql(table, op)
  "ADD COLUMN #{column_definition_sql(op)}"
end
alter_table_add_constraint_sql(table, op) click to toggle source
# File lib/sequel/database/schema_methods.rb, line 475
def alter_table_add_constraint_sql(table, op)
  "ADD #{constraint_definition_sql(op)}"
end
alter_table_drop_column_sql(table, op) click to toggle source
# File lib/sequel/database/schema_methods.rb, line 455
def alter_table_drop_column_sql(table, op)
  "DROP COLUMN #{quote_identifier(op[:name])}#{' CASCADE' if op[:cascade]}"
end
alter_table_drop_constraint_sql(table, op) click to toggle source
# File lib/sequel/database/schema_methods.rb, line 479
def alter_table_drop_constraint_sql(table, op)
  quoted_name = quote_identifier(op[:name]) if op[:name]
  if op[:type] == :foreign_key
    quoted_name ||= quote_identifier(foreign_key_name(table, op[:columns]))
  end
  "DROP CONSTRAINT #{quoted_name}#{' CASCADE' if op[:cascade]}"
end
alter_table_generator_class() click to toggle source

The class used for #alter_table generators.

# File lib/sequel/database/schema_methods.rb, line 437
def alter_table_generator_class
  Schema::AlterTableGenerator
end
alter_table_op_sql(table, op) click to toggle source

SQL fragment for given alter table operation.

# File lib/sequel/database/schema_methods.rb, line 442
def alter_table_op_sql(table, op)
  meth = "alter_table_#{op[:op]}_sql"
  if respond_to?(meth, true)
    send(meth, table, op)
  else
    raise Error, "Unsupported ALTER TABLE operation: #{op[:op]}"
  end
end
alter_table_rename_column_sql(table, op) click to toggle source
# File lib/sequel/database/schema_methods.rb, line 459
def alter_table_rename_column_sql(table, op)
  "RENAME COLUMN #{quote_identifier(op[:name])} TO #{quote_identifier(op[:new_name])}"
end
alter_table_set_column_default_sql(table, op) click to toggle source
# File lib/sequel/database/schema_methods.rb, line 467
def alter_table_set_column_default_sql(table, op)
  "ALTER COLUMN #{quote_identifier(op[:name])} SET DEFAULT #{literal(op[:default])}"
end
alter_table_set_column_null_sql(table, op) click to toggle source
# File lib/sequel/database/schema_methods.rb, line 471
def alter_table_set_column_null_sql(table, op)
  "ALTER COLUMN #{quote_identifier(op[:name])} #{op[:null] ? 'DROP' : 'SET'} NOT NULL"
end
alter_table_set_column_type_sql(table, op) click to toggle source
# File lib/sequel/database/schema_methods.rb, line 463
def alter_table_set_column_type_sql(table, op)
  "ALTER COLUMN #{quote_identifier(op[:name])} TYPE #{type_literal(op)}"
end
alter_table_sql(table, op) click to toggle source

The SQL to execute to modify the DDL for the given table name. op should be one of the operations returned by the AlterTableGenerator.

# File lib/sequel/database/schema_methods.rb, line 489
def alter_table_sql(table, op)
  case op[:op]
  when :add_index
    index_definition_sql(table, op)
  when :drop_index
    drop_index_sql(table, op)
  else
    "ALTER TABLE #{quote_schema_table(table)} #{alter_table_op_sql(table, op)}"
  end
end
alter_table_sql_list(table, operations) click to toggle source

Array of SQL DDL modification statements for the given table, corresponding to the DDL changes specified by the operations.

# File lib/sequel/database/schema_methods.rb, line 502
def alter_table_sql_list(table, operations)
  if supports_combining_alter_table_ops?
    grouped_ops = []
    last_combinable = false
    operations.each do |op|
      if combinable_alter_table_op?(op)
        if sql = alter_table_op_sql(table, op)
          grouped_ops << [] unless last_combinable
          grouped_ops.last << sql
          last_combinable = true
        end
      elsif sql = alter_table_sql(table, op)
        Array(sql).each{|s| grouped_ops << s}
        last_combinable = false
      end
    end
    grouped_ops.map do |gop|
      if gop.is_a?(Array)
        "ALTER TABLE #{quote_schema_table(table)} #{gop.join(', ')}"
      else
        gop
      end
    end
  else
    operations.map{|op| alter_table_sql(table, op)}.flatten.compact
  end
end
apply_alter_table(name, ops) click to toggle source

Apply the changes in the given alter table ops to the table given by name.

# File lib/sequel/database/schema_methods.rb, line 419
def apply_alter_table(name, ops)
  alter_table_sql_list(name, ops).each{|sql| execute_ddl(sql)}
end
apply_alter_table_generator(name, generator) click to toggle source

Apply the operations in the given generator to the table given by name.

# File lib/sequel/database/schema_methods.rb, line 424
def apply_alter_table_generator(name, generator)
  ops = generator.operations

  unless can_add_primary_key_constraint_on_nullable_columns?
    if add_pk = ops.find{|op| op[:op] == :add_constraint && op[:type] == :primary_key}
      ops = add_pk[:columns].map{|column| {:op => :set_column_null, :name => column, :null => false}} + ops
    end
  end

  apply_alter_table(name, ops)
end
auto_increment_sql() click to toggle source

The SQL string specify the autoincrement property, generally used by primary keys.

# File lib/sequel/database/schema_methods.rb, line 532
def auto_increment_sql
  AUTOINCREMENT
end
column_definition_auto_increment_sql(sql, column) click to toggle source

Add auto increment SQL fragment to column creation SQL.

# File lib/sequel/database/schema_methods.rb, line 550
def column_definition_auto_increment_sql(sql, column)
  sql << " #{auto_increment_sql}" if column[:auto_increment]
end
column_definition_collate_sql(sql, column) click to toggle source

Add collate SQL fragment to column creation SQL.

# File lib/sequel/database/schema_methods.rb, line 555
def column_definition_collate_sql(sql, column)
  if collate = column[:collate]
    sql << " COLLATE #{collate}"
  end
end
column_definition_default_sql(sql, column) click to toggle source

Add default SQL fragment to column creation SQL.

# File lib/sequel/database/schema_methods.rb, line 562
def column_definition_default_sql(sql, column)
  sql << " DEFAULT #{literal(column[:default])}" if column.include?(:default)
end
column_definition_null_sql(sql, column) click to toggle source

Add null/not null SQL fragment to column creation SQL.

# File lib/sequel/database/schema_methods.rb, line 567
def column_definition_null_sql(sql, column)
  null = column.fetch(:null, column[:allow_null])
  if null.nil? && !can_add_primary_key_constraint_on_nullable_columns? && column[:primary_key]
    null = false
  end

  case null
  when false
    sql << NOT_NULL
  when true
    sql << NULL
  end
end
column_definition_order() click to toggle source

The order of the column definition, as an array of symbols.

# File lib/sequel/database/schema_methods.rb, line 537
def column_definition_order
  self.class.const_get(:COLUMN_DEFINITION_ORDER)
end
column_definition_primary_key_sql(sql, column) click to toggle source

Add primary key SQL fragment to column creation SQL.

# File lib/sequel/database/schema_methods.rb, line 582
def column_definition_primary_key_sql(sql, column)
  if column[:primary_key]
    if name = column[:primary_key_constraint_name]
      sql << " CONSTRAINT #{quote_identifier(name)}"
    end
    sql << PRIMARY_KEY
  end
end
column_definition_references_sql(sql, column) click to toggle source

Add foreign key reference SQL fragment to column creation SQL.

# File lib/sequel/database/schema_methods.rb, line 592
def column_definition_references_sql(sql, column)
  if column[:table]
    if name = column[:foreign_key_constraint_name]
     sql << " CONSTRAINT #{quote_identifier(name)}"
    end
    sql << column_references_column_constraint_sql(column)
  end
end
column_definition_sql(column) click to toggle source

SQL DDL fragment containing the column creation SQL for the given column.

# File lib/sequel/database/schema_methods.rb, line 542
def column_definition_sql(column)
  sql = String.new
  sql << "#{quote_identifier(column[:name])} #{type_literal(column)}"
  column_definition_order.each{|m| send(:"column_definition_#{m}_sql", sql, column)}
  sql
end
column_definition_unique_sql(sql, column) click to toggle source

Add unique constraint SQL fragment to column creation SQL.

# File lib/sequel/database/schema_methods.rb, line 602
def column_definition_unique_sql(sql, column)
  if column[:unique]
    if name = column[:unique_constraint_name]
      sql << " CONSTRAINT #{quote_identifier(name)}"
    end
    sql << UNIQUE
  end
end
column_list_sql(generator) click to toggle source

SQL for all given columns, used inside a CREATE TABLE block.

# File lib/sequel/database/schema_methods.rb, line 612
def column_list_sql(generator)
  (generator.columns.map{|c| column_definition_sql(c)} + generator.constraints.map{|c| constraint_definition_sql(c)}).join(COMMA_SEPARATOR)
end
column_references_column_constraint_sql(column) click to toggle source

SQL DDL fragment for column foreign key references (column constraints)

# File lib/sequel/database/schema_methods.rb, line 617
def column_references_column_constraint_sql(column)
  column_references_sql(column)
end
column_references_sql(column) click to toggle source

SQL DDL fragment for column foreign key references

# File lib/sequel/database/schema_methods.rb, line 622
def column_references_sql(column)
  sql = String.new
  sql << " REFERENCES #{quote_schema_table(column[:table])}"
  sql << "(#{Array(column[:key]).map{|x| quote_identifier(x)}.join(COMMA_SEPARATOR)})" if column[:key]
  sql << " ON DELETE #{on_delete_clause(column[:on_delete])}" if column[:on_delete]
  sql << " ON UPDATE #{on_update_clause(column[:on_update])}" if column[:on_update]
  constraint_deferrable_sql_append(sql, column[:deferrable])
  sql
end
column_references_table_constraint_sql(constraint) click to toggle source

SQL DDL fragment for table foreign key references (table constraints)

# File lib/sequel/database/schema_methods.rb, line 633
def column_references_table_constraint_sql(constraint)
  "FOREIGN KEY #{literal(constraint[:columns])}#{column_references_sql(constraint)}"
end
combinable_alter_table_op?(op) click to toggle source

Whether the given alter table operation is combinable.

# File lib/sequel/database/schema_methods.rb, line 638
def combinable_alter_table_op?(op)
  # Use a dynamic lookup for easier overriding in adapters
  COMBINABLE_ALTER_TABLE_OPS.include?(op[:op])
end
constraint_deferrable_sql_append(sql, defer) click to toggle source

SQL DDL fragment specifying the deferrable constraint attributes.

# File lib/sequel/database/schema_methods.rb, line 668
def constraint_deferrable_sql_append(sql, defer)
  case defer
  when nil
  when false
    sql << ' NOT DEFERRABLE'
  when :immediate
    sql << ' DEFERRABLE INITIALLY IMMEDIATE'
  else
    sql << ' DEFERRABLE INITIALLY DEFERRED'
  end
end
constraint_definition_sql(constraint) click to toggle source

SQL DDL fragment specifying a constraint on a table.

# File lib/sequel/database/schema_methods.rb, line 644
def constraint_definition_sql(constraint)
  sql = String.new
  sql << "CONSTRAINT #{quote_identifier(constraint[:name])} " if constraint[:name] 
  case constraint[:type]
  when :check
    check = constraint[:check]
    check = check.first if check.is_a?(Array) && check.length == 1
    check = filter_expr(check)
    check = "(#{check})" unless check[0..0] == '(' && check[-1..-1] == ')'
    sql << "CHECK #{check}"
  when :primary_key
    sql << "PRIMARY KEY #{literal(constraint[:columns])}"
  when :foreign_key
    sql << column_references_table_constraint_sql(constraint.merge(:deferrable=>nil))
  when :unique
    sql << "UNIQUE #{literal(constraint[:columns])}"
  else
    raise Error, "Invalid constraint type #{constraint[:type]}, should be :check, :primary_key, :foreign_key, or :unique"
  end
  constraint_deferrable_sql_append(sql, constraint[:deferrable])
  sql
end
create_table_as(name, sql, options) click to toggle source

Run a command to create the table with the given name from the given SELECT sql statement.

# File lib/sequel/database/schema_methods.rb, line 737
def create_table_as(name, sql, options)
  sql = sql.sql if sql.is_a?(Sequel::Dataset)
  run(create_table_as_sql(name, sql, options))
end
create_table_as_sql(name, sql, options) click to toggle source

DDL statement for creating a table from the result of a SELECT statement. sql should be a string representing a SELECT query.

# File lib/sequel/database/schema_methods.rb, line 744
def create_table_as_sql(name, sql, options)
  "#{create_table_prefix_sql(name, options)} AS #{sql}"
end
create_table_from_generator(name, generator, options) click to toggle source

Execute the create table statements using the generator.

# File lib/sequel/database/schema_methods.rb, line 681
def create_table_from_generator(name, generator, options)
  execute_ddl(create_table_sql(name, generator, options))
end
create_table_generator_class() click to toggle source

The class used for #create_table generators.

# File lib/sequel/database/schema_methods.rb, line 686
def create_table_generator_class
  Schema::CreateTableGenerator
end
create_table_indexes_from_generator(name, generator, options) click to toggle source

Execute the create index statements using the generator.

# File lib/sequel/database/schema_methods.rb, line 691
def create_table_indexes_from_generator(name, generator, options)
  e = options[:ignore_index_errors] || options[:if_not_exists]
  generator.indexes.each do |index|
    begin
      index_sql_list(name, [index]).each{|sql| execute_ddl(sql)}
    rescue Error
      raise unless e
    end
  end
end
create_table_prefix_sql(name, options) click to toggle source

DDL fragment for initial part of CREATE TABLE statement

# File lib/sequel/database/schema_methods.rb, line 749
def create_table_prefix_sql(name, options)
  "CREATE #{temporary_table_sql if options[:temp]}TABLE#{' IF NOT EXISTS' if options[:if_not_exists]} #{options[:temp] ? quote_identifier(name) : quote_schema_table(name)}"
end
create_table_sql(name, generator, options) click to toggle source

DDL statement for creating a table with the given name, columns, and options

# File lib/sequel/database/schema_methods.rb, line 703
def create_table_sql(name, generator, options)
  unless supports_named_column_constraints?
    # Split column constraints into table constraints if they have a name
    generator.columns.each do |c|
      if (constraint_name = c.delete(:foreign_key_constraint_name)) && (table = c.delete(:table))
        opts = {}
        opts[:name] = constraint_name
        [:key, :on_delete, :on_update, :deferrable].each{|k| opts[k] = c[k]}
        generator.foreign_key([c[:name]], table, opts)
      end
      if (constraint_name = c.delete(:unique_constraint_name)) && c.delete(:unique)
        generator.unique(c[:name], :name=>constraint_name)
      end
      if (constraint_name = c.delete(:primary_key_constraint_name)) && c.delete(:primary_key)
        generator.primary_key([c[:name]], :name=>constraint_name)
      end
    end
  end

  unless can_add_primary_key_constraint_on_nullable_columns?
    if pk = generator.constraints.find{|op| op[:type] == :primary_key}
      pk[:columns].each do |column|
        if matched_column = generator.columns.find{|gc| gc[:name] == column}
          matched_column[:null] = false
        end
      end
    end
  end

  "#{create_table_prefix_sql(name, options)} (#{column_list_sql(generator)})"
end
create_view_prefix_sql(name, options) click to toggle source

DDL fragment for initial part of CREATE VIEW statement

# File lib/sequel/database/schema_methods.rb, line 754
def create_view_prefix_sql(name, options)
  create_view_sql_append_columns("CREATE #{'OR REPLACE 'if options[:replace]}VIEW #{quote_schema_table(name)}", options[:columns])
end
create_view_sql(name, source, options) click to toggle source

DDL statement for creating a view.

# File lib/sequel/database/schema_methods.rb, line 759
def create_view_sql(name, source, options)
  source = source.sql if source.is_a?(Dataset)
  sql = String.new
  sql << "#{create_view_prefix_sql(name, options)} AS #{source}"
  if check = options[:check]
    sql << " WITH#{' LOCAL' if check == :local} CHECK OPTION"
  end
  sql
end
create_view_sql_append_columns(sql, columns) click to toggle source

Append the column list to the SQL, if a column list is given.

# File lib/sequel/database/schema_methods.rb, line 770
def create_view_sql_append_columns(sql, columns)
  sql = sql.dup
  if columns
    sql << ' ('
    schema_utility_dataset.send(:identifier_list_append, sql, columns)
    sql << ')'
  end
  sql
end
default_index_name(table_name, columns) click to toggle source

Default index name for the table and columns, may be too long for certain databases.

# File lib/sequel/database/schema_methods.rb, line 782
def default_index_name(table_name, columns)
  schema, table = schema_and_table(table_name)
  "#{"#{schema}_" if schema}#{table}_#{columns.map{|c| [String, Symbol].any?{|cl| c.is_a?(cl)} ? c : literal(c).gsub(/\W/, '_')}.join(UNDERSCORE)}_index"
end
drop_index_sql(table, op) click to toggle source

The SQL to drop an index for the table.

# File lib/sequel/database/schema_methods.rb, line 795
def drop_index_sql(table, op)
  "DROP INDEX #{quote_identifier(op[:name] || default_index_name(table, op[:columns]))}"
end
drop_table_sql(name, options) click to toggle source

SQL DDL statement to drop the table with the given name.

# File lib/sequel/database/schema_methods.rb, line 800
def drop_table_sql(name, options)
  "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_schema_table(name)}#{' CASCADE' if options[:cascade]}"
end
drop_view_sql(name, options) click to toggle source

SQL DDL statement to drop a view with the given name.

# File lib/sequel/database/schema_methods.rb, line 805
def drop_view_sql(name, options)
  "DROP VIEW#{' IF EXISTS' if options[:if_exists]} #{quote_schema_table(name)}#{' CASCADE' if options[:cascade]}"
end
filter_expr(*args, &block) click to toggle source

Proxy the #filter_expr call to the dataset, used for creating constraints.

# File lib/sequel/database/schema_methods.rb, line 810
def filter_expr(*args, &block)
  if args.length == 1 && args.first.is_a?(Proc) && !block
    block = args.first
    args = nil
  end
  schema_utility_dataset.literal(schema_utility_dataset.send(:filter_expr, *args, &block))
end
foreign_key_name(table_name, columns) click to toggle source

Get foreign key name for given table and columns.

# File lib/sequel/database/schema_methods.rb, line 788
def foreign_key_name(table_name, columns)
  keys = foreign_key_list(table_name).select{|key| key[:columns] == columns}
  raise(Error, "#{keys.empty? ? 'Missing' : 'Ambiguous'} foreign key for #{columns.inspect}") unless keys.size == 1
  keys.first[:name]
end
index_definition_sql(table_name, index) click to toggle source

SQL DDL statement for creating an index for the table with the given name and index specifications.

# File lib/sequel/database/schema_methods.rb, line 820
def index_definition_sql(table_name, index)
  index_name = index[:name] || default_index_name(table_name, index[:columns])
  raise Error, "Index types are not supported for this database" if index[:type]
  raise Error, "Partial indexes are not supported for this database" if index[:where] && !supports_partial_indexes?
  "CREATE #{'UNIQUE ' if index[:unique]}INDEX #{quote_identifier(index_name)} ON #{quote_schema_table(table_name)} #{literal(index[:columns])}#{" WHERE #{filter_expr(index[:where])}" if index[:where]}"
end
index_sql_list(table_name, indexes) click to toggle source

Array of SQL DDL statements, one for each index specification, for the given table.

# File lib/sequel/database/schema_methods.rb, line 829
def index_sql_list(table_name, indexes)
  indexes.map{|i| index_definition_sql(table_name, i)}
end
join_table_name(hash, options) click to toggle source

Extract the join table name from the arguments given to create_join_table. Also does argument validation for the #create_join_table method.

# File lib/sequel/database/schema_methods.rb, line 835
def join_table_name(hash, options)
  entries = hash.values
  raise Error, "must have 2 entries in hash given to (create|drop)_join_table" unless entries.length == 2
  if options[:name]
    options[:name]
  else
    table_names = entries.map{|e| join_table_name_extract(e)}
    table_names.map(&:to_s).sort.join('_')
  end
end
join_table_name_extract(entry) click to toggle source

Extract an individual join table name, which should either be a string or symbol, or a hash containing one of those as the value for :table.

# File lib/sequel/database/schema_methods.rb, line 848
def join_table_name_extract(entry)
  case entry
  when Symbol, String
    entry
  when Hash
    join_table_name_extract(entry[:table])
  else
    raise Error, "can't extract table name from #{entry.inspect}"
  end
end
on_delete_clause(action) click to toggle source

SQL DDL ON DELETE fragment to use, based on the given action. The following actions are recognized:

:cascade

Delete rows referencing this row.

:no_action

Raise an error if other rows reference this row, allow deferring of the integrity check. This is the default.

:restrict

Raise an error if other rows reference this row, but do not allow deferring the integrity check.

:set_default

Set columns referencing this row to their default value.

:set_null

Set columns referencing this row to NULL.

Any other object given is just converted to a string, with “_” converted to “ ” and upcased.

# File lib/sequel/database/schema_methods.rb, line 872
def on_delete_clause(action)
  action.to_s.gsub("_", " ").upcase
end
on_update_clause(action) click to toggle source

Alias of on_delete_clause, since the two usually behave the same.

# File lib/sequel/database/schema_methods.rb, line 877
def on_update_clause(action)
  on_delete_clause(action)
end
quote_schema_table(table) click to toggle source

Proxy the #quote_schema_table method to the dataset

# File lib/sequel/database/schema_methods.rb, line 882
def quote_schema_table(table)
  schema_utility_dataset.quote_schema_table(table)
end
rename_table_sql(name, new_name) click to toggle source

SQL DDL statement for renaming a table.

# File lib/sequel/database/schema_methods.rb, line 887
def rename_table_sql(name, new_name)
  "ALTER TABLE #{quote_schema_table(name)} RENAME TO #{quote_schema_table(new_name)}"
end
schema_and_table(table_name) click to toggle source

Split the schema information from the table

# File lib/sequel/database/schema_methods.rb, line 892
def schema_and_table(table_name)
  schema_utility_dataset.schema_and_table(table_name)
end
schema_autoincrementing_primary_key?(schema) click to toggle source

Return true if the given column schema represents an autoincrementing primary key.

# File lib/sequel/database/schema_methods.rb, line 897
def schema_autoincrementing_primary_key?(schema)
  !!(schema[:primary_key] && schema[:auto_increment])
end
schema_utility_dataset() click to toggle source

The dataset to use for proxying certain schema methods.

# File lib/sequel/database/schema_methods.rb, line 902
def schema_utility_dataset
  @default_dataset
end
split_qualifiers(table_name) click to toggle source

Split the schema information from the table

# File lib/sequel/database/schema_methods.rb, line 907
def split_qualifiers(table_name)
  schema_utility_dataset.split_qualifiers(table_name)
end
temporary_table_sql() click to toggle source

SQL DDL fragment for temporary table

# File lib/sequel/database/schema_methods.rb, line 912
def temporary_table_sql
  self.class.const_get(:TEMPORARY)
end
type_literal(column) click to toggle source

SQL fragment specifying the type of a given column.

# File lib/sequel/database/schema_methods.rb, line 917
def type_literal(column)
  case column[:type]
  when Class
    type_literal_generic(column)
  when :Bignum
    type_literal_generic_bignum_symbol(column)
  else
    type_literal_specific(column)
  end
end
type_literal_generic(column) click to toggle source

SQL fragment specifying the full type of a column, consider the type with possible modifiers.

# File lib/sequel/database/schema_methods.rb, line 930
def type_literal_generic(column)
  meth = "type_literal_generic_#{column[:type].name.to_s.downcase}"
  if respond_to?(meth, true)
    send(meth, column)
  else
    raise Error, "Unsupported ruby class used as database type: #{column[:type]}"
  end
end
type_literal_generic_bigdecimal(column) click to toggle source

Alias for #type_literal_generic_numeric, to make overriding in a subclass easier.

# File lib/sequel/database/schema_methods.rb, line 940
def type_literal_generic_bigdecimal(column)
  type_literal_generic_numeric(column)
end
type_literal_generic_bignum_symbol(column) click to toggle source

Sequel uses the bigint type by default for :Bignum symbol.

# File lib/sequel/database/schema_methods.rb, line 945
def type_literal_generic_bignum_symbol(column)
  :bigint
end
type_literal_generic_date(column) click to toggle source

Sequel uses the date type by default for Dates.

# File lib/sequel/database/schema_methods.rb, line 950
def type_literal_generic_date(column)
  :date
end
type_literal_generic_datetime(column) click to toggle source

Sequel uses the timestamp type by default for DateTimes.

# File lib/sequel/database/schema_methods.rb, line 955
def type_literal_generic_datetime(column)
  :timestamp
end
type_literal_generic_falseclass(column) click to toggle source

Alias for #type_literal_generic_trueclass, to make overriding in a subclass easier.

# File lib/sequel/database/schema_methods.rb, line 960
def type_literal_generic_falseclass(column)
  type_literal_generic_trueclass(column)
end
type_literal_generic_file(column) click to toggle source

Sequel uses the blob type by default for Files.

# File lib/sequel/database/schema_methods.rb, line 965
def type_literal_generic_file(column)
  :blob
end
type_literal_generic_fixnum(column) click to toggle source

Alias for #type_literal_generic_integer, to make overriding in a subclass easier.

# File lib/sequel/database/schema_methods.rb, line 970
def type_literal_generic_fixnum(column)
  type_literal_generic_integer(column)
end
type_literal_generic_float(column) click to toggle source

Sequel uses the double precision type by default for Floats.

# File lib/sequel/database/schema_methods.rb, line 975
def type_literal_generic_float(column)
  :"double precision"
end
type_literal_generic_integer(column) click to toggle source

Sequel uses the integer type by default for integers

# File lib/sequel/database/schema_methods.rb, line 980
def type_literal_generic_integer(column)
  :integer
end
type_literal_generic_numeric(column) click to toggle source

Sequel uses the numeric type by default for Numerics and BigDecimals. If a size is given, it is used, otherwise, it will default to whatever the database default is for an unsized value.

# File lib/sequel/database/schema_methods.rb, line 987
def type_literal_generic_numeric(column)
  column[:size] ? "numeric(#{Array(column[:size]).join(', ')})" : :numeric
end
type_literal_generic_string(column) click to toggle source

Sequel uses the varchar type by default for Strings. If a size isn't present, Sequel assumes a size of 255. If the :fixed option is used, Sequel uses the char type. If the :text option is used, Sequel uses the :text type.

# File lib/sequel/database/schema_methods.rb, line 995
def type_literal_generic_string(column)
  if column[:text]
    uses_clob_for_text? ? :clob : :text
  elsif column[:fixed]
    "char(#{column[:size]||default_string_column_size})"
  else
    "varchar(#{column[:size]||default_string_column_size})"
  end
end
type_literal_generic_time(column) click to toggle source

Sequel uses the timestamp type by default for Time values. If the :only_time option is used, the time type is used.

# File lib/sequel/database/schema_methods.rb, line 1007
def type_literal_generic_time(column)
  column[:only_time] ? :time : :timestamp
end
type_literal_generic_trueclass(column) click to toggle source

Sequel uses the boolean type by default for TrueClass and FalseClass.

# File lib/sequel/database/schema_methods.rb, line 1012
def type_literal_generic_trueclass(column)
  :boolean
end
type_literal_specific(column) click to toggle source

SQL fragment for the given type of a column if the column is not one of the generic types specified with a ruby class.

# File lib/sequel/database/schema_methods.rb, line 1018
def type_literal_specific(column)
  type = column[:type]
  type = "double precision" if type.to_s == 'double'
  column[:size] ||= default_string_column_size if type.to_s == 'varchar'
  elements = column[:size] || column[:elements]
  "#{type}#{literal(Array(elements)) if elements}#{UNSIGNED if column[:unsigned]}"
end
uses_clob_for_text?() click to toggle source

Whether clob should be used for String :text=>true columns.

# File lib/sequel/database/schema_methods.rb, line 1027
def uses_clob_for_text?
  false
end

3 - Methods that create datasets

↑ top

Public Instance Methods

[](*args) click to toggle source

Returns a dataset for the database. If the first argument is a string, the method acts as an alias for #fetch, returning a dataset for arbitrary SQL, with or without placeholders:

DB['SELECT * FROM items'].all
DB['SELECT * FROM items WHERE name = ?', my_name].all

Otherwise, acts as an alias for #from, setting the primary table for the dataset:

DB[:items].sql #=> "SELECT * FROM items"
# File lib/sequel/database/dataset.rb, line 21
def [](*args)
  args.first.is_a?(String) ? fetch(*args) : from(*args)
end
dataset() click to toggle source

Returns a blank dataset for this database.

DB.dataset # SELECT *
DB.dataset.from(:items) # SELECT * FROM items
# File lib/sequel/database/dataset.rb, line 29
def dataset
  @dataset_class.new(self)
end
fetch(sql, *args, &block) click to toggle source

Fetches records for an arbitrary SQL statement. If a block is given, it is used to iterate over the records:

DB.fetch('SELECT * FROM items'){|r| p r}

The fetch method returns a dataset instance:

DB.fetch('SELECT * FROM items').all

fetch can also perform parameterized queries for protection against SQL injection:

DB.fetch('SELECT * FROM items WHERE name = ?', my_name).all

See caveats listed in Sequel::Dataset#with_sql regarding datasets using custom SQL and the methods that can be called on them.

# File lib/sequel/database/dataset.rb, line 49
def fetch(sql, *args, &block)
  ds = @default_dataset.with_sql(sql, *args)
  ds.each(&block) if block
  ds
end
from(*args, &block) click to toggle source

Returns a new dataset with the from method invoked. If a block is given, it is used as a filter on the dataset.

DB.from(:items) # SELECT * FROM items
DB.from(:items){id > 2} # SELECT * FROM items WHERE (id > 2)
# File lib/sequel/database/dataset.rb, line 60
def from(*args, &block)
  ds = @default_dataset.from(*args)
  if block
    Sequel::Deprecation.deprecate("Sequel::Database#from with a block", "Use .from(*args).where(&block) instead")
    ds.where(&block)
  else
    ds
  end
end
select(*args, &block) click to toggle source

Returns a new dataset with the select method invoked.

DB.select(1) # SELECT 1
DB.select{server_version{}} # SELECT server_version()
DB.select(:id).from(:items) # SELECT id FROM items
# File lib/sequel/database/dataset.rb, line 75
def select(*args, &block)
  @default_dataset.select(*args, &block)
end

4 - Methods relating to adapters, connecting, disconnecting, and sharding

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Constants

ADAPTERS

Array of supported database adapters

Attributes

pool[R]

The connection pool for this Database instance. All Database instances have their own connection pools.

Public Class Methods

adapter_class(scheme) click to toggle source

The Database subclass for the given adapter scheme. Raises Sequel::AdapterNotFound if the adapter could not be loaded.

# File lib/sequel/database/connecting.rb, line 27
def self.adapter_class(scheme)
  return scheme if scheme.is_a?(Class)

  scheme = scheme.to_s.gsub('-', '_').to_sym

  load_adapter(scheme)
end
adapter_scheme() click to toggle source

Returns the scheme symbol for the Database class.

# File lib/sequel/database/connecting.rb, line 36
def self.adapter_scheme
  @scheme
end
connect(conn_string, opts = OPTS) { |db| ... } click to toggle source

Connects to a database. See Sequel.connect.

# File lib/sequel/database/connecting.rb, line 41
def self.connect(conn_string, opts = OPTS)
  case conn_string
  when String
    # SEQUEL5: Remove do
    if match = /\A(jdbc|do):/o.match(conn_string)
      c = adapter_class(match[1].to_sym)
      opts = opts.merge(:orig_opts=>opts.dup)
      opts = {:uri=>conn_string}.merge!(opts)
    else
      uri = URI.parse(conn_string)
      scheme = uri.scheme
      c = adapter_class(scheme)
      uri_options = c.send(:uri_to_options, uri)
      uri.query.split('&').collect{|s| s.split('=')}.each{|k,v| uri_options[k.to_sym] = v if k && !k.empty?} unless uri.query.to_s.strip.empty?
      uri_options.to_a.each{|k,v| uri_options[k] = (defined?(URI::DEFAULT_PARSER) ? URI::DEFAULT_PARSER : URI).unescape(v) if v.is_a?(String)}
      opts = uri_options.merge(opts).merge!(:orig_opts=>opts.dup, :uri=>conn_string, :adapter=>scheme)
    end
  when Hash
    opts = conn_string.merge(opts)
    opts = opts.merge(:orig_opts=>opts.dup)
    c = adapter_class(opts[:adapter_class] || opts[:adapter] || opts['adapter'])
  else
    raise Error, "Sequel::Database.connect takes either a Hash or a String, given: #{conn_string.inspect}"
  end
  # process opts a bit
  opts = opts.inject({}) do |m, (k,v)|
    k = :user if k.to_s == 'username'
    m[k.to_sym] = v
    m
  end
  begin
    db = c.new(opts)
    # SEQUEL5: Default opts[:test] to true
    db.test_connection if opts[:test] && db.send(:typecast_value_boolean, opts[:test])
    if block_given?
      return yield(db)
    end
  ensure
    if block_given?
      db.disconnect if db
      Sequel.synchronize{::Sequel::DATABASES.delete(db)}
    end
  end
  db
end
load_adapter(scheme, opts=OPTS) click to toggle source

Load the adapter from the file system. Raises Sequel::AdapterNotFound if the adapter cannot be loaded, or if the adapter isn't registered correctly after being loaded. Options:

:map

The Hash in which to look for an already loaded adapter (defaults to ADAPTER_MAP).

:subdir

The subdirectory of sequel/adapters to look in, only to be used for loading subadapters.

# File lib/sequel/database/connecting.rb, line 93
def self.load_adapter(scheme, opts=OPTS)
  map = opts[:map] || ADAPTER_MAP
  if subdir = opts[:subdir]
    file = "#{subdir}/#{scheme}"
  else
    file = scheme
  end
  
  unless obj = Sequel.synchronize{map[scheme]}
    # attempt to load the adapter file
    begin
      require "sequel/adapters/#{file}"
    rescue LoadError => e
      # If subadapter file doesn't exist, just return, 
      # using the main adapter class without database customizations.
      return if subdir
      raise Sequel.convert_exception_class(e, AdapterNotFound)
    end
    
    # make sure we actually loaded the adapter
    unless obj = Sequel.synchronize{map[scheme]}
      raise AdapterNotFound, "Could not load #{file} adapter: adapter class not registered in ADAPTER_MAP"
    end
  end

  obj
end
set_shared_adapter_scheme(scheme, mod) click to toggle source

Sets the given module as the shared adapter module for the given scheme. Used to register shared adapters for use by the mock adapter. Example:

# in file sequel/adapters/shared/mydb.rb
module Sequel::MyDB
  Sequel::Database.set_shared_adapter_scheme :mydb, self

  def self.mock_adapter_setup(db)
    # ...
  end

  module DatabaseMethods
    extend Sequel::Database::ResetIdentifierMangling
    # ...
  end

  module DatasetMethods
    # ...
  end
end

would allow the mock adapter to return a Database instance that supports the MyDB syntax via:

Sequel.connect('mock://mydb')
# File lib/sequel/database/connecting.rb, line 164
def self.set_shared_adapter_scheme(scheme, mod)
  Sequel.synchronize{SHARED_ADAPTER_MAP[scheme] = mod}
end
single_threaded() click to toggle source

SEQUEL5: Remove cubrid do swift

# File lib/sequel/database/connecting.rb, line 14
def self.single_threaded
  Sequel::Deprecation.deprecate("Sequel::Database.single_threaded", "Use Sequel.single_threaded instead")
  Sequel.single_threaded
end
single_threaded=(v) click to toggle source
# File lib/sequel/database/connecting.rb, line 19
def self.single_threaded=(v)
  Sequel::Deprecation.deprecate("Sequel::Database.single_threaded=", "Use Sequel.single_threaded= instead")
  Sequel.single_threaded = v
end

Public Instance Methods

adapter_scheme() click to toggle source

Returns the scheme symbol for this instance's class, which reflects which adapter is being used. In some cases, this can be the same as the database_type (for native adapters), in others (i.e. adapters with subadapters), it will be different.

Sequel.connect('jdbc:postgres://...').adapter_scheme # => :jdbc
# File lib/sequel/database/connecting.rb, line 178
def adapter_scheme
  self.class.adapter_scheme
end
add_servers(servers) click to toggle source

Dynamically add new servers or modify server options at runtime. Also adds new servers to the connection pool. Intended for use with master/slave or shard configurations where it is useful to add new server hosts at runtime.

servers argument should be a hash with server name symbol keys and hash or proc values. If a servers key is already in use, it's value is overridden with the value provided.

DB.add_servers(:f=>{:host=>"hash_host_f"})
# File lib/sequel/database/connecting.rb, line 191
def add_servers(servers)
  unless h = @opts[:servers]
    Sequel::Deprecation.deprecate("Calling Database#add_servers on a database that does not use sharding", "This method should only be called if the database supports sharding.")
    # raise Error, "cannot call Database#add_servers on a Database instance that does not use a sharded connection pool" # SEQUEL5
    return
  end

  Sequel.synchronize{h.merge!(servers)}
  @pool.add_servers(servers.keys)
end
database_type() click to toggle source

The database type for this database object, the same as the adapter scheme by default. Should be overridden in adapters (especially shared adapters) to be the correct type, so that even if two separate Database objects are using different adapters you can tell that they are using the same database type. Even better, you can tell that two Database objects that are using the same adapter are connecting to different database types (think JDBC or DataObjects).

Sequel.connect('jdbc:postgres://...').database_type # => :postgres
# File lib/sequel/database/connecting.rb, line 211
def database_type
  adapter_scheme
end
disconnect(opts = OPTS) click to toggle source

Disconnects all available connections from the connection pool. Any connections currently in use will not be disconnected. Options:

:servers

Should be a symbol specifing the server to disconnect from, or an array of symbols to specify multiple servers.

Example:

DB.disconnect # All servers
DB.disconnect(:servers=>:server1) # Single server
DB.disconnect(:servers=>[:server1, :server2]) # Multiple servers
# File lib/sequel/database/connecting.rb, line 225
def disconnect(opts = OPTS)
  pool.disconnect(opts)
end
disconnect_connection(conn) click to toggle source

Should only be called by the connection pool code to disconnect a connection. By default, calls the close method on the connection object, since most adapters use that, but should be overwritten on other adapters.

# File lib/sequel/database/connecting.rb, line 232
def disconnect_connection(conn)
  conn.close
end
each_server(&block) click to toggle source

Yield a new Database instance for every server in the connection pool. Intended for use in sharded environments where there is a need to make schema modifications (DDL queries) on each shard.

DB.each_server{|db| db.create_table(:users){primary_key :id; String :name}}
# File lib/sequel/database/connecting.rb, line 241
def each_server(&block)
  Sequel::Deprecation.deprecate("Database#each_server", "Switching to using Dataset#servers and Database#with_server from the server_block extension: \"DB.servers.each{|s| DB.with_server(s){}}\"")
  raise(Error, "Database#each_server must be passed a block") unless block
  servers.each{|s| self.class.connect(server_opts(s), &block)}
end
remove_servers(*servers) click to toggle source

Dynamically remove existing servers from the connection pool. Intended for use with master/slave or shard configurations where it is useful to remove existing server hosts at runtime.

servers should be symbols or arrays of symbols. If a nonexistent server is specified, it is ignored. If no servers have been specified for this database, no changes are made. If you attempt to remove the :default server, an error will be raised.

DB.remove_servers(:f1, :f2)
# File lib/sequel/database/connecting.rb, line 257
def remove_servers(*servers)
  unless h = @opts[:servers]
    Sequel::Deprecation.deprecate("Calling Database#add_servers on a database that does not use sharding", "This method should only be called if the database supports sharding.")
    # raise Error, "cannot call Database#remove_servers on a Database instance that does not use a sharded connection pool" # SEQUEL5
    return
  end

  servers.flatten.each{|s| Sequel.synchronize{h.delete(s)}}
  @pool.remove_servers(servers)
end
servers() click to toggle source

An array of servers/shards for this Database object.

DB.servers # Unsharded: => [:default]
DB.servers # Sharded:   => [:default, :server1, :server2]
# File lib/sequel/database/connecting.rb, line 272
def servers
  pool.servers
end
single_threaded?() click to toggle source

Returns true if the database is using a single-threaded connection pool.

# File lib/sequel/database/connecting.rb, line 277
def single_threaded?
  @single_threaded
end
synchronize(server=nil) { |conn| ... } click to toggle source

Acquires a database connection, yielding it to the passed block. This is useful if you want to make sure the same connection is used for all database queries in the block. It is also useful if you want to gain direct access to the underlying connection object if you need to do something Sequel does not natively support.

If a server option is given, acquires a connection for that specific server, instead of the :default server.

DB.synchronize do |conn|
  # ...
end
# File lib/sequel/database/connecting.rb, line 294
def synchronize(server=nil)
  @pool.hold(server || :default){|conn| yield conn}
end
test_connection(server=nil) click to toggle source

Attempts to acquire a database connection. Returns true if successful. Will probably raise an Error if unsuccessful. If a server argument is given, attempts to acquire a database connection to the given server/shard.

# File lib/sequel/database/connecting.rb, line 309
def test_connection(server=nil)
  synchronize(server){|conn|}
  true
end
valid_connection?(conn) click to toggle source

Check whether the given connection is currently valid, by running a query against it. If the query fails, the connection should probably be removed from the connection pool.

# File lib/sequel/database/connecting.rb, line 318
def valid_connection?(conn)
  sql = valid_connection_sql
  begin
    log_connection_execute(conn, sql)
  rescue Sequel::DatabaseError, *database_error_classes
    false
  else
    true
  end
end

Private Instance Methods

connection_pool_default_options() click to toggle source

The default options for the connection pool.

# File lib/sequel/database/connecting.rb, line 332
def connection_pool_default_options
  {}
end
server_opts(server) click to toggle source

Return the options for the given server by merging the generic options for all server with the specific options for the given server specified in the :servers option.

# File lib/sequel/database/connecting.rb, line 339
def server_opts(server)
  opts = if @opts[:servers] and server_options = @opts[:servers][server]
    case server_options
    when Hash
      @opts.merge(server_options)
    when Proc
      @opts.merge(server_options.call(self))
    else
      raise Error, 'Server opts should be a hash or proc'
    end
  elsif server.is_a?(Hash)
    @opts.merge(server)
  else
    @opts.dup
  end
  opts.delete(:servers)
  opts
end
valid_connection_sql() click to toggle source

The SQL query to issue to check if a connection is valid.

# File lib/sequel/database/connecting.rb, line 359
def valid_connection_sql
  @valid_connection_sql ||= select(nil).sql
end

5 - Methods that set defaults for created datasets

↑ top

Constants

DatasetClass

The default class to use for datasets

Attributes

identifier_input_method[R]

The identifier input method to use by default for all databases (default: adapter default)

identifier_output_method[R]

The identifier output method to use by default for all databases (default: adapter default)

quote_identifiers[R]

Whether to quote identifiers (columns and tables) by default for all databases (default: adapter default)

dataset_class[R]

The class to use for creating datasets. Should respond to new with the Database argument as the first argument, and an optional options hash.

Public Class Methods

identifier_input_method=(v) click to toggle source

Change the default identifier input method to use for all databases,

# File lib/sequel/database/dataset_defaults.rb, line 29
def self.identifier_input_method=(v)
  Sequel::Deprecation.deprecate("Sequel.identifier_input_method= and Sequel::Database.identifier_input_method=", "Call Sequel::Database#identifier_input_method= instead")
  @identifier_input_method = v.nil? ? false : v
end
identifier_output_method=(v) click to toggle source

Change the default identifier output method to use for all databases,

# File lib/sequel/database/dataset_defaults.rb, line 35
def self.identifier_output_method=(v)
  Sequel::Deprecation.deprecate("Sequel.identifier_output_method= and Sequel::Database.identifier_output_method=", "Call Sequel::Database#identifier_output_method= instead")
  @identifier_output_method = v.nil? ? false : v
end
quote_identifiers=(v) click to toggle source
# File lib/sequel/database/dataset_defaults.rb, line 40
def self.quote_identifiers=(v)
  Sequel::Deprecation.deprecate("Sequel.quote_identifiers= and Sequel::Database.quote_identifiers=", "Call Sequel::Database#quote_identifiers= instead")
  @quote_identifiers = v
end

Public Instance Methods

dataset_class=(c) click to toggle source

If the database has any dataset modules associated with it, use a subclass of the given class that includes the modules as the dataset class.

# File lib/sequel/database/dataset_defaults.rb, line 53
def dataset_class=(c)
  unless @dataset_modules.empty?
    c = Class.new(c)
    @dataset_modules.each{|m| c.send(:include, m)}
  end
  @dataset_class = c
  reset_default_dataset
end
extend_datasets(mod=nil, &block) click to toggle source

Equivalent to extending all datasets produced by the database with a module. What it actually does is use a subclass of the current #dataset_class as the new #dataset_class, and include the module in the subclass. Instead of a module, you can provide a block that is used to create an anonymous module.

This allows you to override any of the dataset methods even if they are defined directly on the dataset class that this Database object uses.

Examples:

# Introspec columns for all of DB's datasets
DB.extend_datasets(Sequel::ColumnsIntrospection)

# Trace all SELECT queries by printing the SQL and the full backtrace
DB.extend_datasets do
  def fetch_rows(sql)
    puts sql
    puts caller
    super
  end
end
# File lib/sequel/database/dataset_defaults.rb, line 84
def extend_datasets(mod=nil, &block)
  raise(Error, "must provide either mod or block, not both") if mod && block
  mod = Module.new(&block) if block
  if @dataset_modules.empty?
   @dataset_modules = [mod]
   @dataset_class = Class.new(@dataset_class)
  else
   @dataset_modules << mod
  end
  @dataset_class.send(:include, mod)
  reset_default_dataset
end

Private Instance Methods

dataset_class_default() click to toggle source

The default dataset class to use for the database

# File lib/sequel/database/dataset_defaults.rb, line 100
def dataset_class_default
  self.class.const_get(:DatasetClass)
end
quote_identifiers_default() click to toggle source

Whether to quote identifiers by default for this database, true by default.

# File lib/sequel/database/dataset_defaults.rb, line 114
def quote_identifiers_default
  true
end
reset_default_dataset() click to toggle source

Reset the default dataset used by most Database methods that create datasets. Usually done after changes to the identifier mangling methods.

# File lib/sequel/database/dataset_defaults.rb, line 107
def reset_default_dataset
  Sequel.synchronize{@symbol_literal_cache.clear}
  @default_dataset = dataset
end

6 - Methods relating to logging

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Attributes

log_connection_info[RW]

Whether to include information about the connection in use when logging queries.

log_warn_duration[RW]

Numeric specifying the duration beyond which queries are logged at warn level instead of info level.

loggers[RW]

Array of SQL loggers to use for this database.

sql_log_level[RW]

Log level at which to log SQL queries. This is actually the method sent to the logger, so it should be the method name symbol. The default is :info, it can be set to :debug to log at DEBUG level.

Public Instance Methods

log_connection_yield(sql, conn, args=nil) { || ... } click to toggle source

Yield to the block, logging any errors at error level to all loggers, and all other queries with the duration at warn or info level.

# File lib/sequel/database/logging.rb, line 43
def log_connection_yield(sql, conn, args=nil)
  return yield if @loggers.empty?
  sql = "#{connection_info(conn) if conn && log_connection_info}#{sql}#{"; #{args.inspect}" if args}"
  start = Time.now
  begin
    yield
  rescue => e
    log_exception(e, sql)
    raise
  ensure
    log_duration(Time.now - start, sql) unless e
  end
end
log_exception(exception, message) click to toggle source

Log a message at error level, with information about the exception.

# File lib/sequel/database/logging.rb, line 26
def log_exception(exception, message)
  log_each(:error, "#{exception.class}: #{exception.message.strip if exception.message}: #{message}")
end
log_info(message, args=nil) click to toggle source

Log a message at level info to all loggers.

# File lib/sequel/database/logging.rb, line 31
def log_info(message, args=nil)
  log_each(:info, args ? "#{message}; #{args.inspect}" : message)
end
log_yield(sql, args=nil, &block) click to toggle source

Yield to the block, logging any errors at error level to all loggers, and all other queries with the duration at warn or info level.

# File lib/sequel/database/logging.rb, line 37
def log_yield(sql, args=nil, &block)
  log_connection_yield(sql, nil, args, &block)
end
logger=(logger) click to toggle source

Remove any existing loggers and just use the given logger:

DB.logger = Logger.new($stdout)
# File lib/sequel/database/logging.rb, line 60
def logger=(logger)
  @loggers = Array(logger)
end

Private Instance Methods

connection_info(conn) click to toggle source

String including information about the connection, for use when logging connection info.

# File lib/sequel/database/logging.rb, line 68
def connection_info(conn)
  "(conn: #{conn.__id__}) "
end
log_connection_execute(conn, sql) click to toggle source

Log the given SQL and then execute it on the connection, used by the transaction code.

# File lib/sequel/database/logging.rb, line 74
def log_connection_execute(conn, sql)
  log_connection_yield(sql, conn){conn.send(connection_execute_method, sql)}
end
log_duration(duration, message) click to toggle source

Log message with message prefixed by duration at info level, or warn level if duration is greater than log_warn_duration.

# File lib/sequel/database/logging.rb, line 80
def log_duration(duration, message)
  log_each((lwd = log_warn_duration and duration >= lwd) ? :warn : sql_log_level, "(#{sprintf('%0.6fs', duration)}) #{message}")
end
log_each(level, message) click to toggle source

Log message at level (which should be :error, :warn, or :info) to all loggers.

# File lib/sequel/database/logging.rb, line 86
def log_each(level, message)
  @loggers.each{|logger| logger.send(level, message)}
end

7 - Miscellaneous methods

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Constants

CHECK_CONSTRAINT_SQLSTATES
DEFAULT_DATABASE_ERROR_REGEXPS

Empty exception regexp to class map, used by default if Sequel doesn't have specific support for the database in use.

DEFAULT_STRING_COLUMN_SIZE

The general default size for string columns for all Sequel::Database instances.

EXTENSIONS

Hash of extension name symbols to callable objects to load the extension into the Database object (usually by extending it with a module defined in the extension).

FOREIGN_KEY_CONSTRAINT_SQLSTATES
LEADING_ZERO_RE

Used for checking/removing leading zeroes from strings so they don't get interpreted as octal.

LEADING_ZERO_REP

:nocov: Replacement string when replacing leading zeroes.

NOT_NULL_CONSTRAINT_SQLSTATES
SCHEMA_TYPE_CLASSES

Mapping of schema type symbols to class or arrays of classes for that symbol.

SERIALIZATION_CONSTRAINT_SQLSTATES
UNIQUE_CONSTRAINT_SQLSTATES

Attributes

default_string_column_size[RW]

The specific default size of string columns for this Sequel::Database, usually 255 by default.

opts[R]

The options hash for this database

timezone[W]

Set the timezone to use for this database, overridding Sequel.database_timezone.

Public Class Methods

after_initialize(&block) click to toggle source

Register a hook that will be run when a new Database is instantiated. It is called with the new database handle.

# File lib/sequel/database/misc.rb, line 46
def self.after_initialize(&block)
  raise Error, "must provide block to after_initialize" unless block
  Sequel.synchronize do
    previous = @initialize_hook
    @initialize_hook = Proc.new do |db|
      previous.call(db)
      block.call(db)
    end
  end
end
extension(*extensions) click to toggle source

Apply an extension to all Database objects created in the future.

# File lib/sequel/database/misc.rb, line 58
def self.extension(*extensions)
  after_initialize{|db| db.extension(*extensions)}
end
new(opts = OPTS) click to toggle source

Constructs a new instance of a database connection with the specified options hash.

Accepts the following options:

:default_string_column_size

The default size of string columns, 255 by default.

:identifier_mangling

Whether to support non-default identifier mangling for the current database.

:logger

A specific logger to use.

:loggers

An array of loggers to use.

:name

A name to use for the Database object.

:preconnect

Whether to automatically connect to the maximum number of servers.

:quote_identifiers

Whether to quote identifiers.

:servers

A hash specifying a server/shard specific options, keyed by shard symbol .

:single_threaded

Whether to use a single-threaded connection pool.

:sql_log_level

Method to use to log SQL to a logger, :info by default.

All options given are also passed to the connection pool.

# File lib/sequel/database/misc.rb, line 122
def initialize(opts = OPTS)
  @opts ||= opts
  @opts = connection_pool_default_options.merge(@opts)
  @loggers = Array(@opts[:logger]) + Array(@opts[:loggers])
  @opts[:servers] = {} if @opts[:servers].is_a?(String)
  @sharded = !!@opts[:servers]
  @opts[:adapter_class] = self.class
  @opts[:single_threaded] = @single_threaded = typecast_value_boolean(@opts.fetch(:single_threaded, Sequel.single_threaded))
  @default_string_column_size = @opts[:default_string_column_size] || DEFAULT_STRING_COLUMN_SIZE

  @schemas = {}
  @prepared_statements = {}
  @transactions = {}
  @symbol_literal_cache = {}

  @timezone = nil

  @dataset_class = dataset_class_default
  @cache_schema = typecast_value_boolean(@opts.fetch(:cache_schema, true))
  @dataset_modules = []
  @loaded_extensions = []
  @schema_type_classes = SCHEMA_TYPE_CLASSES.dup

  self.sql_log_level = @opts[:sql_log_level] ? @opts[:sql_log_level].to_sym : :info
  self.log_warn_duration = @opts[:log_warn_duration]
  self.log_connection_info = typecast_value_boolean(@opts[:log_connection_info])

  @pool = ConnectionPool.get_pool(self, @opts)

  reset_default_dataset
  adapter_initialize
  if typecast_value_boolean(@opts.fetch(:identifier_mangling, true))
    extension(:_deprecated_identifier_mangling)
  end

  unless typecast_value_boolean(@opts[:keep_reference]) == false
    Sequel.synchronize{::Sequel::DATABASES.push(self)}
  end
  Sequel::Database.run_after_initialize(self)
  if typecast_value_boolean(@opts[:preconnect]) && @pool.respond_to?(:preconnect, true)
    concurrent = typecast_value_string(@opts[:preconnect]) == "concurrently"
    @pool.send(:preconnect, concurrent)
  end
end
register_extension(ext, mod=nil, &block) click to toggle source

Register an extension callback for Database objects. ext should be the extension name symbol, and mod should either be a Module that the database is extended with, or a callable object called with the database object. If mod is not provided, a block can be provided and is treated as the mod object.

# File lib/sequel/database/misc.rb, line 67
def self.register_extension(ext, mod=nil, &block)
  if mod
    raise(Error, "cannot provide both mod and block to Database.register_extension") if block
    if mod.is_a?(Module)
      block = proc{|db| db.extend(mod)}
    else
      block = mod
    end
  end
  Sequel.synchronize{EXTENSIONS[ext] = block}
end
run_after_initialize(instance) click to toggle source

Run the ::after_initialize hook for the given instance.

# File lib/sequel/database/misc.rb, line 80
def self.run_after_initialize(instance)
  @initialize_hook.call(instance)
end

Private Class Methods

uri_to_options(uri) click to toggle source

Converts a uri to an options hash. These options are then passed to a newly created database object.

# File lib/sequel/database/misc.rb, line 86
def self.uri_to_options(uri)
  {
    :user => uri.user,
    :password => uri.password,
    :port => uri.port,
    :host => RUBY_VERSION < '1.9.3' ? uri.host : uri.hostname,
    :database => (m = /\/(.*)/.match(uri.path)) && (m[1])
  }
end

Public Instance Methods

cast_type_literal(type) click to toggle source

Cast the given type to a literal type

DB.cast_type_literal(Float) # double precision
DB.cast_type_literal(:foo) # foo
# File lib/sequel/database/misc.rb, line 194
def cast_type_literal(type)
  type_literal(:type=>type)
end
extension(*exts) click to toggle source

Load an extension into the receiver. In addition to requiring the extension file, this also modifies the database to work with the extension (usually extending it with a module defined in the extension file). If no related extension file exists or the extension does not have specific support for Database objects, an Error will be raised. Returns self.

# File lib/sequel/database/misc.rb, line 203
def extension(*exts)
  Sequel.extension(*exts)
  exts.each do |ext|
    if pr = Sequel.synchronize{EXTENSIONS[ext]}
      unless Sequel.synchronize{@loaded_extensions.include?(ext)}
        Sequel.synchronize{@loaded_extensions << ext}
        pr.call(self)
      end
    else
      raise(Error, "Extension #{ext} does not have specific support handling individual databases (try: Sequel.extension #{ext.inspect})")
    end
  end
  self
end
freeze() click to toggle source

Freeze internal data structures for the Database instance.

Calls superclass method
# File lib/sequel/database/misc.rb, line 168
def freeze
  valid_connection_sql
  metadata_dataset
  @opts.freeze
  @loggers.freeze
  @pool.freeze
  @dataset_class.freeze
  @dataset_modules.freeze
  @schema_type_classes.freeze
  @loaded_extensions.freeze
  # SEQUEL5: Frozen by default, remove this
  @default_dataset.freeze
  metadata_dataset.freeze
  super
end
from_application_timestamp(v) click to toggle source

Convert the given timestamp from the application's timezone, to the databases's timezone or the default database timezone if the database does not have a timezone.

# File lib/sequel/database/misc.rb, line 221
def from_application_timestamp(v)
  Sequel.convert_output_timestamp(v, timezone)
end
initialize_copy(_) click to toggle source
Calls superclass method
# File lib/sequel/database/misc.rb, line 184
def initialize_copy(_)
  Sequel::Deprecation.deprecate("Database#dup and #clone", "Use Sequel.connect to create a new Database instance")
  # raise(Error, "cannot dup/clone a Sequel::Database instance") # SEQUEL5
  super
end
inspect() click to toggle source

Returns a string representation of the database object including the class name and connection URI and options used when connecting (if any).

# File lib/sequel/database/misc.rb, line 227
def inspect
  a = []
  a << uri.inspect if uri
  if (oo = opts[:orig_opts]) && !oo.empty?
    a << oo.inspect
  end
  "#<#{self.class}: #{a.join(' ')}>"
end
literal(v) click to toggle source

Proxy the literal call to the dataset.

DB.literal(1) # 1
DB.literal(:a) # a
DB.literal('a') # 'a'
# File lib/sequel/database/misc.rb, line 241
def literal(v)
  schema_utility_dataset.literal(v)
end
literal_symbol(sym) click to toggle source

Return the literalized version of the symbol if cached, or nil if it is not cached.

# File lib/sequel/database/misc.rb, line 247
def literal_symbol(sym)
  Sequel.synchronize{@symbol_literal_cache[sym]}
end
literal_symbol_set(sym, lit) click to toggle source

Set the cached value of the literal symbol.

# File lib/sequel/database/misc.rb, line 252
def literal_symbol_set(sym, lit)
  Sequel.synchronize{@symbol_literal_cache[sym] = lit}
end
prepared_statement(name) click to toggle source

Synchronize access to the prepared statements cache.

# File lib/sequel/database/misc.rb, line 257
def prepared_statement(name)
  Sequel.synchronize{prepared_statements[name]}
end
quote_identifier(v) click to toggle source

Proxy the #quote_identifier method to the dataset, useful for quoting unqualified identifiers for use outside of datasets.

# File lib/sequel/database/misc.rb, line 264
def quote_identifier(v)
  schema_utility_dataset.quote_identifier(v)
end
schema_type_class(type) click to toggle source

Return ruby class or array of classes for the given type symbol.

# File lib/sequel/database/misc.rb, line 269
def schema_type_class(type)
  @schema_type_classes[type]
end
serial_primary_key_options() click to toggle source

Default serial primary key options, used by the table creation code.

# File lib/sequel/database/misc.rb, line 275
def serial_primary_key_options
  {:primary_key => true, :type => Integer, :auto_increment => true}
end
set_prepared_statement(name, ps) click to toggle source

Cache the prepared statement object at the given name.

# File lib/sequel/database/misc.rb, line 280
def set_prepared_statement(name, ps)
  Sequel.synchronize{prepared_statements[name] = ps}
end
sharded?() click to toggle source

Whether this database instance uses multiple servers, either for sharding or for master/slave.

# File lib/sequel/database/misc.rb, line 286
def sharded?
  @sharded
end
timezone() click to toggle source

The timezone to use for this database, defaulting to Sequel.database_timezone.

# File lib/sequel/database/misc.rb, line 291
def timezone
  @timezone || Sequel.database_timezone
end
to_application_timestamp(v) click to toggle source

Convert the given timestamp to the application's timezone, from the databases's timezone or the default database timezone if the database does not have a timezone.

# File lib/sequel/database/misc.rb, line 298
def to_application_timestamp(v)
  Sequel.convert_timestamp(v, timezone)
end
typecast_value(column_type, value) click to toggle source

Typecast the value to the given column_type. Calls typecast_value_#{column_type} if the method exists, otherwise returns the value. This method should raise Sequel::InvalidValue if assigned value is invalid.

# File lib/sequel/database/misc.rb, line 307
def typecast_value(column_type, value)
  return nil if value.nil?
  meth = "typecast_value_#{column_type}"
  begin
    respond_to?(meth, true) ? send(meth, value) : value
  rescue ArgumentError, TypeError => e
    raise Sequel.convert_exception_class(e, InvalidValue)
  end
end
uri() click to toggle source

Returns the URI use to connect to the database. If a URI was not used when connecting, returns nil.

# File lib/sequel/database/misc.rb, line 319
def uri
  opts[:uri]
end
url() click to toggle source

Explicit alias of uri for easier subclassing.

# File lib/sequel/database/misc.rb, line 324
def url
  uri
end

Private Instance Methods

_typecast_value_string_to_decimal(value) click to toggle source

Typecast a string to a BigDecimal

# File lib/sequel/database/misc.rb, line 464
def _typecast_value_string_to_decimal(value)
  BigDecimal.new(value)
end
adapter_initialize() click to toggle source

Per adapter initialization method, empty by default.

# File lib/sequel/database/misc.rb, line 331
def adapter_initialize
end
blank_object?(obj) click to toggle source

Returns true when the object is considered blank. The only objects that are blank are nil, false, strings with all whitespace, and ones that respond true to empty?

# File lib/sequel/database/misc.rb, line 338
def blank_object?(obj)
  return obj.blank? if obj.respond_to?(:blank?)
  case obj
  when NilClass, FalseClass
    true
  when Numeric, TrueClass
    false
  when String
    obj.strip.empty?
  else
    obj.respond_to?(:empty?) ? obj.empty? : false
  end
end
database_error_class(exception, opts) click to toggle source

Return the Sequel::DatabaseError subclass to wrap the given exception in.

# File lib/sequel/database/misc.rb, line 361
def database_error_class(exception, opts)
  database_specific_error_class(exception, opts) || DatabaseError
end
database_error_regexps() click to toggle source

An enumerable yielding pairs of regexps and exception classes, used to match against underlying driver exception messages in order to raise a more specific Sequel::DatabaseError subclass.

# File lib/sequel/database/misc.rb, line 355
def database_error_regexps
  DEFAULT_DATABASE_ERROR_REGEXPS
end
database_exception_sqlstate(exception, opts) click to toggle source

Return the SQLState for the given exception, if one can be determined

# File lib/sequel/database/misc.rb, line 367
def database_exception_sqlstate(exception, opts)
  nil
end
database_specific_error_class(exception, opts) click to toggle source

Return a specific Sequel::DatabaseError exception class if one is appropriate for the underlying exception, or nil if there is no specific exception class.

# File lib/sequel/database/misc.rb, line 374
def database_specific_error_class(exception, opts)
  return DatabaseDisconnectError if disconnect_error?(exception, opts)

  if sqlstate = database_exception_sqlstate(exception, opts)
    if klass = database_specific_error_class_from_sqlstate(sqlstate)
      return klass
    end
  else
    database_error_regexps.each do |regexp, klss|
      return klss if exception.message =~ regexp
    end
  end

  nil
end
database_specific_error_class_from_sqlstate(sqlstate) click to toggle source

Given the SQLState, return the appropriate DatabaseError subclass.

# File lib/sequel/database/misc.rb, line 396
def database_specific_error_class_from_sqlstate(sqlstate)
  case sqlstate
  when *NOT_NULL_CONSTRAINT_SQLSTATES
    NotNullConstraintViolation
  when *FOREIGN_KEY_CONSTRAINT_SQLSTATES
    ForeignKeyConstraintViolation
  when *UNIQUE_CONSTRAINT_SQLSTATES
    UniqueConstraintViolation
  when *CHECK_CONSTRAINT_SQLSTATES
    CheckConstraintViolation
  when *SERIALIZATION_CONSTRAINT_SQLSTATES
    SerializationFailure
  end
end
disconnect_error?(exception, opts) click to toggle source

Return true if exception represents a disconnect error, false otherwise.

# File lib/sequel/database/misc.rb, line 412
def disconnect_error?(exception, opts)
  opts[:disconnect]
end
raise_error(exception, opts=OPTS) click to toggle source

Convert the given exception to an appropriate Sequel::DatabaseError subclass, keeping message and traceback.

# File lib/sequel/database/misc.rb, line 418
def raise_error(exception, opts=OPTS)
  if !opts[:classes] || Array(opts[:classes]).any?{|c| exception.is_a?(c)}
    raise Sequel.convert_exception_class(exception, database_error_class(exception, opts))
  else
    raise exception
  end
end
typecast_value_blob(value) click to toggle source

Typecast the value to an SQL::Blob

# File lib/sequel/database/misc.rb, line 427
def typecast_value_blob(value)
  value.is_a?(Sequel::SQL::Blob) ? value : Sequel::SQL::Blob.new(value)
end
typecast_value_boolean(value) click to toggle source

Typecast the value to true, false, or nil

# File lib/sequel/database/misc.rb, line 432
def typecast_value_boolean(value)
  case value
  when false, 0, "0", /\Af(alse)?\z/i, /\Ano?\z/i
    false
  else
    blank_object?(value) ? nil : true
  end
end
typecast_value_date(value) click to toggle source

Typecast the value to a Date

# File lib/sequel/database/misc.rb, line 442
def typecast_value_date(value)
  case value
  when DateTime, Time
    Date.new(value.year, value.month, value.day)
  when Date
    value
  when String
    Sequel.string_to_date(value)
  when Hash
    Date.new(*[:year, :month, :day].map{|x| (value[x] || value[x.to_s]).to_i})
  else
    raise InvalidValue, "invalid value for Date: #{value.inspect}"
  end
end
typecast_value_datetime(value) click to toggle source

Typecast the value to a DateTime or Time depending on Sequel.datetime_class

# File lib/sequel/database/misc.rb, line 458
def typecast_value_datetime(value)
  Sequel.typecast_to_application_timestamp(value)
end
typecast_value_decimal(value) click to toggle source

Typecast the value to a BigDecimal

# File lib/sequel/database/misc.rb, line 487
def typecast_value_decimal(value)
  case value
  when BigDecimal
    value
  when Numeric
    BigDecimal.new(value.to_s)
  when String
    _typecast_value_string_to_decimal(value)
  else
    raise InvalidValue, "invalid value for BigDecimal: #{value.inspect}"
  end
end
typecast_value_float(value) click to toggle source

Typecast the value to a Float

# File lib/sequel/database/misc.rb, line 501
def typecast_value_float(value)
  Float(value)
end
typecast_value_integer(value) click to toggle source

Typecast the value to an Integer

# File lib/sequel/database/misc.rb, line 510
def typecast_value_integer(value)
  (value.is_a?(String) && value =~ LEADING_ZERO_RE) ? Integer(value, 10) : Integer(value)
end
typecast_value_string(value) click to toggle source

Typecast the value to a String

# File lib/sequel/database/misc.rb, line 525
def typecast_value_string(value)
  case value
  when Hash, Array
    raise Sequel::InvalidValue, "invalid value for String: #{value.inspect}"
  else
    value.to_s
  end
end
typecast_value_time(value) click to toggle source

Typecast the value to a Time

# File lib/sequel/database/misc.rb, line 535
def typecast_value_time(value)
  case value
  when Time
    if value.is_a?(SQLTime)
      value
    else
      # specifically check for nsec == 0 value to work around JRuby 1.6 ruby 1.9 mode bug
      SQLTime.create(value.hour, value.min, value.sec, (value.respond_to?(:nsec) && value.nsec != 0) ? value.nsec/1000.0 : value.usec)
    end
  when String
    Sequel.string_to_time(value)
  when Hash
    SQLTime.create(*[:hour, :minute, :second].map{|x| (value[x] || value[x.to_s]).to_i})
  else
    raise Sequel::InvalidValue, "invalid value for Time: #{value.inspect}"
  end
end

8 - Methods related to database transactions

↑ top

Constants

SQL_BEGIN
SQL_COMMIT
SQL_RELEASE_SAVEPOINT
SQL_ROLLBACK
SQL_ROLLBACK_TO_SAVEPOINT
SQL_SAVEPOINT
TRANSACTION_BEGIN
TRANSACTION_COMMIT
TRANSACTION_ISOLATION_LEVELS
TRANSACTION_ROLLBACK

Attributes

transaction_isolation_level[RW]

The default transaction isolation level for this database, used for all future transactions. For MSSQL, this should be set to something if you ever plan to use the :isolation option to #transaction, as on MSSQL if affects all future transactions on the same connection.

Public Instance Methods

after_commit(opts=OPTS) { || ... } click to toggle source

If a transaction is not currently in process, yield to the block immediately. Otherwise, add the block to the list of blocks to call after the currently in progress transaction commits (and only if it commits). Options:

:server

The server/shard to use.

# File lib/sequel/database/transactions.rb, line 40
def after_commit(opts=OPTS, &block)
  raise Error, "must provide block to after_commit" unless block
  synchronize(opts[:server]) do |conn|
    if h = _trans(conn)
      raise Error, "cannot call after_commit in a prepared transaction" if h[:prepare]
      add_transaction_hook(conn, :after_commit, block)
    else
      yield
    end
  end
end
after_rollback(opts=OPTS, &block) click to toggle source

If a transaction is not currently in progress, ignore the block. Otherwise, add the block to the list of the blocks to call after the currently in progress transaction rolls back (and only if it rolls back). Options:

:server

The server/shard to use.

# File lib/sequel/database/transactions.rb, line 57
def after_rollback(opts=OPTS, &block)
  raise Error, "must provide block to after_rollback" unless block
  synchronize(opts[:server]) do |conn|
    if h = _trans(conn)
      raise Error, "cannot call after_rollback in a prepared transaction" if h[:prepare]
      add_transaction_hook(conn, :after_rollback, block)
    end
  end
end
in_transaction?(opts=OPTS) click to toggle source

Return true if already in a transaction given the options, false otherwise. Respects the :server option for selecting a shard.

# File lib/sequel/database/transactions.rb, line 70
def in_transaction?(opts=OPTS)
  synchronize(opts[:server]){|conn| !!_trans(conn)}
end
rollback_checker(opts=OPTS) click to toggle source

Returns a proc that you can call to check if the transaction has been rolled back. The proc will return nil if the transaction is still in progress, true if the transaction was rolled back, and false if it was committed. Raises an Error if called outside a transaction. Respects the :server option for selecting a shard.

# File lib/sequel/database/transactions.rb, line 80
def rollback_checker(opts=OPTS)
  synchronize(opts[:server]) do |conn|
    raise Error, "not in a transaction" unless t = _trans(conn)
    t[:rollback_checker] ||= proc{Sequel.synchronize{t[:rolled_back]}}
  end
end
transaction(opts=OPTS) { |conn| ... } click to toggle source

Starts a database transaction. When a database transaction is used, either all statements are successful or none of the statements are successful. Note that MySQL MyISAM tables do not support transactions.

The following general options are respected:

:auto_savepoint

Automatically use a savepoint for #transaction calls inside this transaction block.

:isolation

The transaction isolation level to use for this transaction, should be :uncommitted, :committed, :repeatable, or :serializable, used if given and the database/adapter supports customizable transaction isolation levels.

:num_retries

The number of times to retry if the :retry_on option is used. The default is 5 times. Can be set to nil to retry indefinitely, but that is not recommended.

:before_retry

Proc to execute before rertrying if the :retry_on option is used. Called with two arguments: the number of retry attempts (counting the current one) and the error the last attempt failed with.

:prepare

A string to use as the transaction identifier for a prepared transaction (two-phase commit), if the database/adapter supports prepared transactions.

:retry_on

An exception class or array of exception classes for which to automatically retry the transaction. Can only be set if not inside an existing transaction. Note that this should not be used unless the entire transaction block is idempotent, as otherwise it can cause non-idempotent behavior to execute multiple times.

:rollback

Can the set to :reraise to reraise any Sequel::Rollback exceptions raised, or :always to always rollback even if no exceptions occur (useful for testing).

:server

The server to use for the transaction. Set to :default, :read_only, or whatever symbol you used in the connect string when naming your servers.

:savepoint

Whether to create a new savepoint for this transaction, only respected if the database/adapter supports savepoints. By default Sequel will reuse an existing transaction, so if you want to use a savepoint you must use this option. If the surrounding transaction uses :auto_savepoint, you can set this to false to not use a savepoint. If the value given for this option is :only, it will only create a savepoint if it is inside a transacation.

PostgreSQL specific options:

:deferrable

(9.1+) If present, set to DEFERRABLE if true or NOT DEFERRABLE if false.

:read_only

If present, set to READ ONLY if true or READ WRITE if false.

:synchronous

if non-nil, set synchronous_commit appropriately. Valid values true, :on, false, :off, :local (9.1+), and :remote_write (9.2+).

# File lib/sequel/database/transactions.rb, line 134
def transaction(opts=OPTS, &block)
  opts = Hash[opts]
  if retry_on = opts[:retry_on]
    tot_retries = opts.fetch(:num_retries, 5)
    num_retries = 0 unless tot_retries.nil?
    begin
      opts[:retry_on] = nil
      opts[:retrying] = true
      transaction(opts, &block)
    rescue *retry_on => e
      if num_retries
        num_retries += 1
        if num_retries <= tot_retries
          opts[:before_retry].call(num_retries, e) if opts[:before_retry]
          retry
        end
      else
        retry
      end
      raise
    end
  else
    synchronize(opts[:server]) do |conn|
      if opts[:savepoint] == :only
        if supports_savepoints?
          if _trans(conn)
            opts[:savepoint] = true
          else
            return yield(conn)
          end
        else
          opts[:savepoint] = false
        end
      end

      if already_in_transaction?(conn, opts)
        if opts[:rollback] == :always && !opts.has_key?(:savepoint)
          if supports_savepoints? 
            opts[:savepoint] = true
          else
            raise Sequel::Error, "cannot set :rollback=>:always transaction option if already inside a transaction"
          end
        end

        if opts[:savepoint] != false && (stack = _trans(conn)[:savepoints]) && stack.last
          opts[:savepoint] = true
        end

        unless opts[:savepoint]
          if opts[:retrying]
            raise Sequel::Error, "cannot set :retry_on options if you are already inside a transaction"
          end
          return yield(conn)
        end
      end

      _transaction(conn, opts, &block)
    end
  end
end

Private Instance Methods

_trans(conn) click to toggle source

Synchronize access to the current transactions, returning the hash of options for the current transaction (if any)

# File lib/sequel/database/transactions.rb, line 245
def _trans(conn)
  Sequel.synchronize{@transactions[conn]}
end
_transaction(conn, opts=OPTS) { |conn| ... } click to toggle source

Internal generic transaction method. Any exception raised by the given block will cause the transaction to be rolled back. If the exception is not a Sequel::Rollback, the error will be reraised. If no exception occurs inside the block, the transaction is commited.

# File lib/sequel/database/transactions.rb, line 201
def _transaction(conn, opts=OPTS)
  rollback = opts[:rollback]
  begin
    add_transaction(conn, opts)
    begin_transaction(conn, opts)
    if rollback == :always
      begin
        ret = yield(conn)
      rescue Exception => e1
        raise e1
      ensure
        raise ::Sequel::Rollback unless e1
      end
    else
      yield(conn)
    end
  rescue Exception => e
    begin
      rollback_transaction(conn, opts)
    rescue Exception
    end
    transaction_error(e, :conn=>conn, :rollback=>rollback)
    ret
  ensure
    begin
      committed = commit_or_rollback_transaction(e, conn, opts)
    rescue Exception => e2
      begin
        raise_error(e2, :classes=>database_error_classes, :conn=>conn)
      rescue Sequel::DatabaseError => e4
        begin
          rollback_transaction(conn, opts)
        ensure
          raise e4
        end
      end
    ensure
      remove_transaction(conn, committed)
    end
  end
end
add_transaction(conn, opts) click to toggle source

Add the current thread to the list of active transactions

# File lib/sequel/database/transactions.rb, line 250
def add_transaction(conn, opts)
  hash = transaction_options(conn, opts)

  if supports_savepoints?
    if t = _trans(conn)
      t[:savepoints].push(opts[:auto_savepoint])
      return
    else
      hash[:savepoints] = [opts[:auto_savepoint]]
      if (prep = opts[:prepare]) && supports_prepared_transactions?
        hash[:prepare] = prep
      end
    end
  elsif (prep = opts[:prepare]) && supports_prepared_transactions?
    hash[:prepare] = prep
  end

  Sequel.synchronize{@transactions[conn] = hash}
end
add_transaction_hook(conn, type, block) click to toggle source

Set the given callable as a hook to be called. Type should be either :after_commit or :after_rollback.

# File lib/sequel/database/transactions.rb, line 272
def add_transaction_hook(conn, type, block)
  hooks = _trans(conn)[type] ||= []
  hooks << block
end
already_in_transaction?(conn, opts) click to toggle source

Whether the current thread/connection is already inside a transaction

# File lib/sequel/database/transactions.rb, line 278
def already_in_transaction?(conn, opts)
  _trans(conn) && (!supports_savepoints? || !opts[:savepoint])
end
begin_new_transaction(conn, opts) click to toggle source

Start a new database connection on the given connection

# File lib/sequel/database/transactions.rb, line 299
def begin_new_transaction(conn, opts)
  log_connection_execute(conn, begin_transaction_sql)
  set_transaction_isolation(conn, opts)
end
begin_savepoint(conn, opts) click to toggle source

Issue query to begin a new savepoint.

# File lib/sequel/database/transactions.rb, line 289
def begin_savepoint(conn, opts)
  log_connection_execute(conn, begin_savepoint_sql(savepoint_level(conn)-1))
end
begin_savepoint_sql(depth) click to toggle source

SQL to start a new savepoint

# File lib/sequel/database/transactions.rb, line 294
def begin_savepoint_sql(depth)
  SQL_SAVEPOINT % depth
end
begin_transaction(conn, opts=OPTS) click to toggle source

Start a new database transaction or a new savepoint on the given connection.

# File lib/sequel/database/transactions.rb, line 305
def begin_transaction(conn, opts=OPTS)
  if supports_savepoints?
    if savepoint_level(conn) > 1
      begin_savepoint(conn, opts)
    else
      begin_new_transaction(conn, opts)
    end
  else
    begin_new_transaction(conn, opts)
  end
end
begin_transaction_sql() click to toggle source

SQL to BEGIN a transaction.

# File lib/sequel/database/transactions.rb, line 318
def begin_transaction_sql
  SQL_BEGIN
end
commit_or_rollback_transaction(exception, conn, opts) click to toggle source

Whether to commit the current transaction. Thread.current.status is checked because Thread#kill skips rescue blocks (so exception would be nil), but the transaction should still be rolled back. On Ruby 1.9 (but not 1.8 or 2.0), the thread status will still be “run”, so Thread#kill will erroneously commit the transaction, and there isn't a workaround.

# File lib/sequel/database/transactions.rb, line 327
def commit_or_rollback_transaction(exception, conn, opts)
  if exception
    false
  else
    if Thread.current.status == 'aborting'
      rollback_transaction(conn, opts)
      false
    else
      commit_transaction(conn, opts)
      true
    end
  end
end
commit_savepoint_sql(depth) click to toggle source

SQL to commit a savepoint

# File lib/sequel/database/transactions.rb, line 342
def commit_savepoint_sql(depth)
  SQL_RELEASE_SAVEPOINT % depth
end
commit_transaction(conn, opts=OPTS) click to toggle source

Commit the active transaction on the connection

# File lib/sequel/database/transactions.rb, line 347
def commit_transaction(conn, opts=OPTS)
  if supports_savepoints?
    depth = savepoint_level(conn)
    log_connection_execute(conn, depth > 1 ? commit_savepoint_sql(depth-1) : commit_transaction_sql)
  else
    log_connection_execute(conn, commit_transaction_sql)
  end
end
commit_transaction_sql() click to toggle source

SQL to COMMIT a transaction.

# File lib/sequel/database/transactions.rb, line 357
def commit_transaction_sql
  SQL_COMMIT
end
connection_execute_method() click to toggle source

Method called on the connection object to execute SQL on the database, used by the transaction code.

# File lib/sequel/database/transactions.rb, line 363
def connection_execute_method
  :execute
end
database_error_classes() click to toggle source

Which transaction errors to translate, blank by default.

# File lib/sequel/database/transactions.rb, line 368
def database_error_classes
  []
end
remove_transaction(conn, committed) click to toggle source

Remove the current thread from the list of active transactions

# File lib/sequel/database/transactions.rb, line 381
def remove_transaction(conn, committed)
  callbacks = transaction_hooks(conn, committed)

  if transaction_finished?(conn)
    h = @transactions[conn]
    rolled_back = !committed
    Sequel.synchronize{h[:rolled_back] = rolled_back}
    Sequel.synchronize{@transactions.delete(conn)}
  end

  callbacks.each(&:call) if callbacks
end
rollback_savepoint_sql(depth) click to toggle source

SQL to rollback to a savepoint

# File lib/sequel/database/transactions.rb, line 395
def rollback_savepoint_sql(depth)
  SQL_ROLLBACK_TO_SAVEPOINT % depth
end
rollback_transaction(conn, opts=OPTS) click to toggle source

Rollback the active transaction on the connection

# File lib/sequel/database/transactions.rb, line 400
def rollback_transaction(conn, opts=OPTS)
  if supports_savepoints?
    depth = savepoint_level(conn)
    log_connection_execute(conn, depth > 1 ? rollback_savepoint_sql(depth-1) : rollback_transaction_sql)
  else
    log_connection_execute(conn, rollback_transaction_sql)
  end
end
rollback_transaction_sql() click to toggle source

SQL to ROLLBACK a transaction.

# File lib/sequel/database/transactions.rb, line 410
def rollback_transaction_sql
  SQL_ROLLBACK
end
savepoint_level(conn) click to toggle source

Current savepoint level.

# File lib/sequel/database/transactions.rb, line 427
def savepoint_level(conn)
  _trans(conn)[:savepoints].length
end
set_transaction_isolation(conn, opts) click to toggle source

Set the transaction isolation level on the given connection

# File lib/sequel/database/transactions.rb, line 415
def set_transaction_isolation(conn, opts)
  if supports_transaction_isolation_levels? and level = opts.fetch(:isolation, transaction_isolation_level)
    log_connection_execute(conn, set_transaction_isolation_sql(level))
  end
end
set_transaction_isolation_sql(level) click to toggle source

SQL to set the transaction isolation level

# File lib/sequel/database/transactions.rb, line 422
def set_transaction_isolation_sql(level)
  "SET TRANSACTION ISOLATION LEVEL #{TRANSACTION_ISOLATION_LEVELS[level]}"
end
transaction_error(e, opts=OPTS) click to toggle source

Raise a database error unless the exception is an Rollback.

# File lib/sequel/database/transactions.rb, line 432
def transaction_error(e, opts=OPTS)
  if e.is_a?(Rollback)
    raise e if opts[:rollback] == :reraise
  else
    raise_error(e, opts.merge(:classes=>database_error_classes))
  end
end
transaction_finished?(conn) click to toggle source

Finish a subtransaction. If savepoints are supported, pops the current tansaction off the savepoint stack.

# File lib/sequel/database/transactions.rb, line 442
def transaction_finished?(conn)
  if supports_savepoints?
    stack = _trans(conn)[:savepoints]
    stack.pop
    stack.empty?
  else
    true
  end
end
transaction_hooks(conn, committed) click to toggle source

Retrieve the transaction hooks that should be run for the given connection and commit status.

# File lib/sequel/database/transactions.rb, line 374
def transaction_hooks(conn, committed)
  if !supports_savepoints? || savepoint_level(conn) == 1
    _trans(conn)[committed ? :after_commit : :after_rollback]
  end
end
transaction_options(conn, opts) click to toggle source

Derive the transaction hash from the options passed to the transaction. Meant to be overridden.

# File lib/sequel/database/transactions.rb, line 284
def transaction_options(conn, opts)
  {}
end

9 - Methods that describe what the database supports

↑ top

Public Instance Methods

global_index_namespace?() click to toggle source

Whether the database uses a global namespace for the index. If false, the indexes are going to be namespaced per table.

# File lib/sequel/database/features.rb, line 13
def global_index_namespace?
  true
end
supports_create_table_if_not_exists?() click to toggle source

Whether the database supports CREATE TABLE IF NOT EXISTS syntax, false by default.

# File lib/sequel/database/features.rb, line 19
def supports_create_table_if_not_exists?
  false
end
supports_deferrable_constraints?() click to toggle source

Whether the database supports deferrable constraints, false by default as few databases do.

# File lib/sequel/database/features.rb, line 25
def supports_deferrable_constraints?
  false
end
supports_deferrable_foreign_key_constraints?() click to toggle source

Whether the database supports deferrable foreign key constraints, false by default as few databases do.

# File lib/sequel/database/features.rb, line 31
def supports_deferrable_foreign_key_constraints?
  supports_deferrable_constraints?
end
supports_drop_table_if_exists?() click to toggle source

Whether the database supports DROP TABLE IF EXISTS syntax, default is the same as supports_create_table_if_not_exists?.

# File lib/sequel/database/features.rb, line 37
def supports_drop_table_if_exists?
  supports_create_table_if_not_exists?
end
supports_foreign_key_parsing?() click to toggle source

Whether the database supports Database#foreign_key_list for parsing foreign keys.

# File lib/sequel/database/features.rb, line 43
def supports_foreign_key_parsing?
  respond_to?(:foreign_key_list)
end
supports_index_parsing?() click to toggle source

Whether the database supports Database#indexes for parsing indexes.

# File lib/sequel/database/features.rb, line 48
def supports_index_parsing?
  respond_to?(:indexes)
end
supports_partial_indexes?() click to toggle source

Whether the database supports partial indexes (indexes on a subset of a table).

# File lib/sequel/database/features.rb, line 53
def supports_partial_indexes?
  false
end
supports_prepared_transactions?() click to toggle source

Whether the database and adapter support prepared transactions (two-phase commit), false by default.

# File lib/sequel/database/features.rb, line 59
def supports_prepared_transactions?
  false
end
supports_savepoints?() click to toggle source

Whether the database and adapter support savepoints, false by default.

# File lib/sequel/database/features.rb, line 64
def supports_savepoints?
  false
end
supports_savepoints_in_prepared_transactions?() click to toggle source

Whether the database and adapter support savepoints inside prepared transactions (two-phase commit), default is false.

# File lib/sequel/database/features.rb, line 70
def supports_savepoints_in_prepared_transactions?
  supports_prepared_transactions? && supports_savepoints?
end
supports_schema_parsing?() click to toggle source

Whether the database supports schema parsing via #schema.

# File lib/sequel/database/features.rb, line 75
def supports_schema_parsing?
  respond_to?(:schema_parse_table, true)
end
supports_table_listing?() click to toggle source

Whether the database supports Database#tables for getting list of tables.

# File lib/sequel/database/features.rb, line 80
def supports_table_listing?
  respond_to?(:tables)
end
supports_transaction_isolation_levels?() click to toggle source

Whether the database and adapter support transaction isolation levels, false by default.

# File lib/sequel/database/features.rb, line 90
def supports_transaction_isolation_levels?
  false
end
supports_transactional_ddl?() click to toggle source

Whether DDL statements work correctly in transactions, false by default.

# File lib/sequel/database/features.rb, line 95
def supports_transactional_ddl?
  false
end
supports_view_listing?() click to toggle source

Whether the database supports Database#views for getting list of views.

# File lib/sequel/database/features.rb, line 85
def supports_view_listing?
  respond_to?(:views)
end
supports_views_with_check_option?() click to toggle source

Whether CREATE VIEW … WITH CHECK OPTION is supported, false by default.

# File lib/sequel/database/features.rb, line 100
def supports_views_with_check_option?
  !!view_with_check_option_support
end
supports_views_with_local_check_option?() click to toggle source

Whether CREATE VIEW … WITH LOCAL CHECK OPTION is supported, false by default.

# File lib/sequel/database/features.rb, line 105
def supports_views_with_local_check_option?
  view_with_check_option_support == :local
end

Private Instance Methods

can_add_primary_key_constraint_on_nullable_columns?() click to toggle source

Whether the database supports adding primary key constraints on NULLable columns, automatically making them NOT NULL. If false, the columns must be set NOT NULL before the primary key constraint is added.

# File lib/sequel/database/features.rb, line 114
def can_add_primary_key_constraint_on_nullable_columns?
  true
end
folds_unquoted_identifiers_to_uppercase?() click to toggle source

Whether this dataset considers unquoted identifiers as uppercase. True by default as that is the SQL standard

# File lib/sequel/database/features.rb, line 120
def folds_unquoted_identifiers_to_uppercase?
  true
end
supports_combining_alter_table_ops?() click to toggle source

Whether the database supports combining multiple alter table operations into a single query, false by default.

# File lib/sequel/database/features.rb, line 126
def supports_combining_alter_table_ops?
  false
end
supports_create_or_replace_view?() click to toggle source

Whether the database supports CREATE OR REPLACE VIEW. If not, support will be emulated by dropping the view first. false by default.

# File lib/sequel/database/features.rb, line 132
def supports_create_or_replace_view?
  false
end
supports_named_column_constraints?() click to toggle source

Whether the database supports named column constraints. True by default. Those that don't support named column constraints have to have column constraints converted to table constraints if the column constraints have names.

# File lib/sequel/database/features.rb, line 140
def supports_named_column_constraints?
  true
end
view_with_check_option_support() click to toggle source

Don't advertise support for WITH CHECK OPTION by default.

# File lib/sequel/database/features.rb, line 145
def view_with_check_option_support
  nil
end