module Sequel::MySQL::DatasetMethods

Dataset methods shared by datasets that use MySQL databases.

Constants

APOS
APOS_RE
BACKSLASH
BACKSLASH_RE
BACKTICK
BACKTICK_RE
BINARY
BLOB_START
BOOL_FALSE
BOOL_TRUE
CAST_BITCOMP_CLOSE
CAST_BITCOMP_OPEN
COMMA
COMMA_SEPARATOR
CONCAT
CURRENT_TIMESTAMP_56
DOUBLE_APOS
DOUBLE_BACKTICK
EMPTY_BLOB
EMPTY_COLUMNS
EMPTY_VALUES
EQ
EQ_VALUES
ESCAPE
EXPLAIN
EXPLAIN_EXTENDED
FOR_SHARE
FROM
GROUP_BY
HSTAR
IGNORE
LIKE
LIMIT
MATCH_AGAINST
MATCH_AGAINST_BOOLEAN
NATURAL_LEFT_JOIN
NON_SQL_OPTIONS
NOT_SPACE
ONLY_OFFSET

Comes directly from MySQL's documentation, used for queries with limits without offsets

ON_DUPLICATE_KEY_UPDATE
PAREN_CLOSE
PAREN_OPEN
QUAD_BACKSLASH
REGEXP
SPACE
SQL_CALC_FOUND_ROWS
STRAIGHT_JOIN
WITH_ROLLUP

Public Instance Methods

calc_found_rows() click to toggle source

Sets up the select methods to use SQL_CALC_FOUND_ROWS option.

dataset.calc_found_rows.limit(10)
# SELECT SQL_CALC_FOUND_ROWS * FROM table LIMIT 10
# File lib/sequel/adapters/shared/mysql.rb, line 700
def calc_found_rows
  clone(:calc_found_rows => true)
end
complex_expression_sql_append(sql, op, args) click to toggle source

MySQL specific syntax for LIKE/REGEXP searches, as well as string concatenation.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 640
def complex_expression_sql_append(sql, op, args)
  case op
  when :IN, :"NOT IN"
    ds = args.at(1)
    if ds.is_a?(Sequel::Dataset) && ds.opts[:limit]
      super(sql, op, [args.at(0), ds.from_self])
    else
      super
    end
  when :~, :'!~', :'~*', :'!~*', :LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE'
    sql << PAREN_OPEN
    literal_append(sql, args.at(0))
    sql << SPACE
    sql << 'NOT ' if [:'NOT LIKE', :'NOT ILIKE', :'!~', :'!~*'].include?(op)
    sql << ([:~, :'!~', :'~*', :'!~*'].include?(op) ? REGEXP : LIKE)
    sql << SPACE
    sql << BINARY if [:~, :'!~', :LIKE, :'NOT LIKE'].include?(op)
    literal_append(sql, args.at(1))
    if [:LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE'].include?(op)
      sql << ESCAPE
      literal_append(sql, BACKSLASH)
    end
    sql << PAREN_CLOSE
  when :'||'
    if args.length > 1
      sql << CONCAT
      array_sql_append(sql, args)
    else
      literal_append(sql, args.at(0))
    end
  when :'B~'
    sql << CAST_BITCOMP_OPEN
    literal_append(sql, args.at(0))
    sql << CAST_BITCOMP_CLOSE
  else
    super
  end
end
constant_sql_append(sql, constant) click to toggle source

MySQL's CURRENT_TIMESTAMP does not use fractional seconds, even if the database itself supports fractional seconds. If MySQL 5.6.4+ is being used, use a value that will return fractional seconds.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 683
def constant_sql_append(sql, constant)
  if constant == :CURRENT_TIMESTAMP && supports_timestamp_usecs?
    sql << CURRENT_TIMESTAMP_56
  else
    super
  end
end
delete_from(*tables) click to toggle source

Sets up the select methods to delete from if deleting from a joined dataset:

DB[:a].join(:b, :a_id=>:id).delete
# DELETE a FROM a INNER JOIN b ON (b.a_id = a.id)

DB[:a].join(:b, :a_id=>:id).delete_from(:a, :b).delete
# DELETE a, b FROM a INNER JOIN b ON (b.a_id = a.id)
# File lib/sequel/adapters/shared/mysql.rb, line 712
def delete_from(*tables)
  clone(:delete_from=>tables)
end
distinct(*args) click to toggle source

Use GROUP BY instead of DISTINCT ON if arguments are provided.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 692
def distinct(*args)
  args.empty? ? super : group(*args)
end
explain(opts=OPTS) click to toggle source

Return the results of an EXPLAIN query as a string. Options:

:extended

Use EXPLAIN EXPTENDED instead of EXPLAIN if true.

# File lib/sequel/adapters/shared/mysql.rb, line 718
def explain(opts=OPTS)
  # Load the PrettyTable class, needed for explain output
  Sequel.extension(:_pretty_table) unless defined?(Sequel::PrettyTable)

  ds = db.send(:metadata_dataset).with_sql((opts[:extended] ? EXPLAIN_EXTENDED : EXPLAIN) + select_sql).naked
  rows = ds.all
  Sequel::PrettyTable.string(rows, ds.columns)
end
for_share() click to toggle source

Return a cloned dataset which will use LOCK IN SHARE MODE to lock returned rows.

# File lib/sequel/adapters/shared/mysql.rb, line 728
def for_share
  lock_style(:share)
end
full_text_sql(cols, terms, opts = OPTS) click to toggle source

MySQL specific full text search syntax.

# File lib/sequel/adapters/shared/mysql.rb, line 738
def full_text_sql(cols, terms, opts = OPTS)
  terms = terms.join(' ') if terms.is_a?(Array)
  SQL::PlaceholderLiteralString.new((opts[:boolean] ? MATCH_AGAINST_BOOLEAN : MATCH_AGAINST), [Array(cols), terms])
end
insert_ignore() click to toggle source

Sets up the insert methods to use INSERT IGNORE. Useful if you have a unique key and want to just skip inserting rows that violate the unique key restriction.

dataset.insert_ignore.multi_insert(
 [{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]
)
# INSERT IGNORE INTO tablename (name, value) VALUES (a, 1), (b, 2)
# File lib/sequel/adapters/shared/mysql.rb, line 772
def insert_ignore
  clone(:insert_ignore=>true)
end
join_table(type, table, expr=nil, opts=OPTS, &block) click to toggle source

Transforms an CROSS JOIN to an INNER JOIN if the expr is not nil. Raises an error on use of :full_outer type, since MySQL doesn't support it.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 745
def join_table(type, table, expr=nil, opts=OPTS, &block)
  type = :inner if (type == :cross) && !expr.nil?
  raise(Sequel::Error, "MySQL doesn't support FULL OUTER JOIN") if type == :full_outer
  super(type, table, expr, opts, &block)
end
join_type_sql(join_type) click to toggle source

Transforms :natural_inner to NATURAL LEFT JOIN and straight to STRAIGHT_JOIN.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 753
def join_type_sql(join_type)
  case join_type
  when :straight
    STRAIGHT_JOIN
  when :natural_inner
    NATURAL_LEFT_JOIN
  else
    super
  end
end
on_duplicate_key_update(*args) click to toggle source

Sets up the insert methods to use ON DUPLICATE KEY UPDATE If you pass no arguments, ALL fields will be updated with the new values. If you pass the fields you want then ONLY those field will be updated. If you pass a hash you can customize the values (for example, to increment a numeric field).

Useful if you have a unique key and want to update inserting rows that violate the unique key restriction.

dataset.on_duplicate_key_update.multi_insert(
 [{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]
)
# INSERT INTO tablename (name, value) VALUES (a, 1), (b, 2)
# ON DUPLICATE KEY UPDATE name=VALUES(name), value=VALUES(value)

dataset.on_duplicate_key_update(:value).multi_insert(
  [{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]
)
# INSERT INTO tablename (name, value) VALUES (a, 1), (b, 2)
# ON DUPLICATE KEY UPDATE value=VALUES(value)

dataset.on_duplicate_key_update(
  :value => Sequel.lit('value + VALUES(value)')
).multi_insert(
  [{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]
)
# INSERT INTO tablename (name, value) VALUES (a, 1), (b, 2)
# ON DUPLICATE KEY UPDATE value=value + VALUES(value)
# File lib/sequel/adapters/shared/mysql.rb, line 805
def on_duplicate_key_update(*args)
  clone(:on_duplicate_key_update => args)
end
quoted_identifier_append(sql, c) click to toggle source

MySQL uses the nonstandard ` (backtick) for quoting identifiers.

# File lib/sequel/adapters/shared/mysql.rb, line 810
def quoted_identifier_append(sql, c)
  sql << BACKTICK << c.to_s.gsub(BACKTICK_RE, DOUBLE_BACKTICK) << BACKTICK
end
supports_derived_column_lists?() click to toggle source

MySQL does not support derived column lists

# File lib/sequel/adapters/shared/mysql.rb, line 815
def supports_derived_column_lists?
  false
end
supports_distinct_on?() click to toggle source

MySQL can emulate DISTINCT ON with its non-standard GROUP BY implementation, though the rows returned cannot be made deterministic through ordering.

# File lib/sequel/adapters/shared/mysql.rb, line 821
def supports_distinct_on?
  true
end
supports_group_rollup?() click to toggle source

MySQL supports GROUP BY WITH ROLLUP (but not CUBE)

# File lib/sequel/adapters/shared/mysql.rb, line 826
def supports_group_rollup?
  true
end
supports_intersect_except?() click to toggle source

MySQL does not support INTERSECT or EXCEPT

# File lib/sequel/adapters/shared/mysql.rb, line 831
def supports_intersect_except?
  false
end
supports_limits_in_correlated_subqueries?() click to toggle source

MySQL does not support limits in correlated subqueries (or any subqueries that use IN).

# File lib/sequel/adapters/shared/mysql.rb, line 836
def supports_limits_in_correlated_subqueries?
  false
end
supports_modifying_joins?() click to toggle source

MySQL supports modifying joined datasets

# File lib/sequel/adapters/shared/mysql.rb, line 841
def supports_modifying_joins?
  true
end
supports_ordered_distinct_on?() click to toggle source

MySQL's DISTINCT ON emulation using GROUP BY does not respect the queries ORDER BY clause.

# File lib/sequel/adapters/shared/mysql.rb, line 847
def supports_ordered_distinct_on?
  false
end
supports_regexp?() click to toggle source

MySQL supports pattern matching via regular expressions

# File lib/sequel/adapters/shared/mysql.rb, line 852
def supports_regexp?
  true
end
supports_timestamp_usecs?() click to toggle source

MySQL does support fractional timestamps in literal timestamps, but it ignores them. Also, using them seems to cause problems on 1.9. Since they are ignored anyway, not using them is probably best.

# File lib/sequel/adapters/shared/mysql.rb, line 859
def supports_timestamp_usecs?
  db.supports_timestamp_usecs?
end
update_ignore() click to toggle source

Sets up the update methods to use UPDATE IGNORE. Useful if you have a unique key and want to just skip updating rows that violate the unique key restriction.

dataset.update_ignore.update({:name => 'a', :value => 1})
# UPDATE IGNORE tablename SET name = 'a', value = 1
# File lib/sequel/adapters/shared/mysql.rb, line 869
def update_ignore
  clone(:update_ignore=>true)
end

Private Instance Methods

check_not_limited!(type) click to toggle source

Allow update and delete for limited datasets, unless there is an offset.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 876
def check_not_limited!(type)
  super if type == :truncate || @opts[:offset]
end
delete_from_sql(sql) click to toggle source

Consider the first table in the joined dataset is the table to delete from, but include the others for the purposes of selecting rows.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 882
def delete_from_sql(sql)
  if joined_dataset?
    sql << SPACE
    tables = @opts[:delete_from] || @opts[:from][0..0]
    source_list_append(sql, tables)
    sql << FROM
    source_list_append(sql, @opts[:from])
    select_join_sql(sql)
  else
    super
  end
end
delete_limit_sql(sql)
Alias for: limit_sql
insert_columns_sql(sql) click to toggle source

MySQL doesn't use the SQL standard DEFAULT VALUES.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 896
def insert_columns_sql(sql)
  values = opts[:values]
  if values.is_a?(Array) && values.empty?
    sql << EMPTY_COLUMNS
  else
    super
  end
end
insert_ignore_sql(sql) click to toggle source

MySQL supports INSERT IGNORE INTO

# File lib/sequel/adapters/shared/mysql.rb, line 906
def insert_ignore_sql(sql)
  sql << IGNORE if opts[:insert_ignore]
end
insert_on_duplicate_key_update_sql(sql) click to toggle source

MySQL supports INSERT … ON DUPLICATE KEY UPDATE

# File lib/sequel/adapters/shared/mysql.rb, line 916
def insert_on_duplicate_key_update_sql(sql)
  if update_cols = opts[:on_duplicate_key_update]
    update_vals = nil

    if update_cols.empty?
      update_cols = columns
    elsif update_cols.last.is_a?(Hash)
      update_vals = update_cols.last
      update_cols = update_cols[0..-2]
    end

    sql << ON_DUPLICATE_KEY_UPDATE
    c = false
    co = COMMA
    values = EQ_VALUES
    endp = PAREN_CLOSE
    update_cols.each do |col|
      sql << co if c
      quote_identifier_append(sql, col)
      sql << values
      quote_identifier_append(sql, col)
      sql << endp
      c ||= true
    end
    if update_vals
      eq = EQ
      update_vals.map do |col,v| 
        sql << co if c
        quote_identifier_append(sql, col)
        sql << eq
        literal_append(sql, v)
        c ||= true
      end
    end
  end
end
insert_values_sql(sql) click to toggle source

MySQL doesn't use the standard DEFAULT VALUES for empty values.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 954
def insert_values_sql(sql)
  values = opts[:values]
  if values.is_a?(Array) && values.empty?
    sql << EMPTY_VALUES
  else
    super
  end
end
limit_sql(sql) click to toggle source

MySQL allows a LIMIT in DELETE and UPDATE statements.

# File lib/sequel/adapters/shared/mysql.rb, line 964
def limit_sql(sql)
  if l = @opts[:limit]
    sql << LIMIT
    literal_append(sql, l)
  end
end
literal_blob_append(sql, v) click to toggle source

MySQL uses a preceding X for hex escaping strings

# File lib/sequel/adapters/shared/mysql.rb, line 974
def literal_blob_append(sql, v)
  if v.empty?
    sql << EMPTY_BLOB
  else
    sql << BLOB_START << v.unpack(HSTAR).first
  end
end
literal_false() click to toggle source

Use 0 for false on MySQL

# File lib/sequel/adapters/shared/mysql.rb, line 983
def literal_false
  BOOL_FALSE
end
literal_float(v) click to toggle source

Raise error for infinitate and NaN values

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 988
def literal_float(v)
  if v.infinite? || v.nan?
    raise InvalidValue, "Infinite floats and NaN values are not valid on MySQL"
  else
    super
  end
end
literal_string_append(sql, v) click to toggle source

SQL fragment for String. Doubles \ and ' by default.

# File lib/sequel/adapters/shared/mysql.rb, line 997
def literal_string_append(sql, v)
  sql << APOS << v.gsub(BACKSLASH_RE, QUAD_BACKSLASH).gsub(APOS_RE, DOUBLE_APOS) << APOS
end
literal_true() click to toggle source

Use 1 for true on MySQL

# File lib/sequel/adapters/shared/mysql.rb, line 1002
def literal_true
  BOOL_TRUE
end
multi_insert_sql_strategy() click to toggle source

MySQL supports multiple rows in INSERT.

# File lib/sequel/adapters/shared/mysql.rb, line 1007
def multi_insert_sql_strategy
  :values
end
non_sql_options() click to toggle source

Dataset options that do not affect the generated SQL.

# File lib/sequel/adapters/shared/mysql.rb, line 1012
def non_sql_options
  NON_SQL_OPTIONS
end
select_calc_found_rows_sql(sql) click to toggle source

MySQL specific SQL_CALC_FOUND_ROWS option

# File lib/sequel/adapters/shared/mysql.rb, line 1028
def select_calc_found_rows_sql(sql)
  sql << SQL_CALC_FOUND_ROWS if opts[:calc_found_rows]
end
select_lock_sql(sql) click to toggle source

Support FOR SHARE locking when using the :share lock style.

Calls superclass method
# File lib/sequel/adapters/shared/mysql.rb, line 1023
def select_lock_sql(sql)
  @opts[:lock] == :share ? (sql << FOR_SHARE) : super
end
select_only_offset_sql(sql) click to toggle source
# File lib/sequel/adapters/shared/mysql.rb, line 1016
def select_only_offset_sql(sql)
  sql << LIMIT
  literal_append(sql, @opts[:offset])
  sql << ONLY_OFFSET
end
update_ignore_sql(sql) click to toggle source

MySQL supports UPDATE IGNORE

# File lib/sequel/adapters/shared/mysql.rb, line 911
def update_ignore_sql(sql)
  sql << IGNORE if opts[:update_ignore]
end
update_limit_sql(sql)
Alias for: limit_sql
uses_with_rollup?() click to toggle source

MySQL uses WITH ROLLUP syntax.

# File lib/sequel/adapters/shared/mysql.rb, line 1033
def uses_with_rollup?
  true
end