Module Sequel::Model::ClassMethods
In: lib/sequel/model/base.rb

Class methods for Sequel::Model that implement basic model functionality.

  • All of the method names in Model::DATASET_METHODS have class methods created that call the Model‘s dataset with the method of the same name with the given arguments.

Methods

External Aliases

with_sql -> fetch
  Returns a copy of the model‘s dataset with custom SQL
  Artist.fetch("SELECT * FROM artists WHERE name LIKE 'A%'")
  Artist.fetch("SELECT * FROM artists WHERE id = ?", 1)

Attributes

allowed_columns  [R]  Which columns should be the only columns allowed in a call to a mass assignment method (e.g. set) (default: not set, so all columns not otherwise restricted are allowed).
dataset_method_modules  [R]  Array of modules that extend this model‘s dataset. Stored so that if the model‘s dataset is changed, it will be extended with all of these modules.
dataset_methods  [R]  Hash of dataset methods with method name keys and proc values that are stored so when the dataset changes, methods defined with def_dataset_method will be applied to the new dataset.
plugins  [R]  Array of plugin modules loaded by this class
  Sequel::Model.plugins
  # => [Sequel::Model, Sequel::Model::Associations]
primary_key  [R]  The primary key for the class. Sequel can determine this automatically for many databases, but not all, so you may need to set it manually. If not determined automatically, the default is :id.
raise_on_save_failure  [RW]  Whether to raise an error instead of returning nil on a failure to save/create/save_changes/etc due to a validation failure or a before_* hook returning false.
raise_on_typecast_failure  [RW]  Whether to raise an error when unable to typecast data for a column (default: true). This should be set to false if you want to use validations to display nice error messages to the user (e.g. most web applications). You can use the validates_not_string validations (from either the validation_helpers or validation_class_methods standard plugins) in connection with option to check for typecast failures for columns that aren‘t blobs or strings.
require_modification  [RW]  Whether to raise an error if an UPDATE or DELETE query related to a model instance does not modify exactly 1 row. If set to false, Sequel will not check the number of rows modified (default: true).
restricted_columns  [R]  Which columns are specifically restricted in a call to set/update/new/etc. (default: not set). Some columns are restricted regardless of this setting, such as the primary key column and columns in Model::RESTRICTED_SETTER_METHODS.
simple_pk  [R]  Should be the literal primary key column name if this Model‘s table has a simple primary key, or nil if the model has a compound primary key or no primary key.
simple_table  [R]  Should be the literal table name if this Model‘s dataset is a simple table (no select, order, join, etc.), or nil otherwise. This and simple_pk are used for an optimization in Model.[].
strict_param_setting  [RW]  Whether new/set/update and their variants should raise an error if an invalid key is used. A key is invalid if no setter method exists for that key or the access to the setter method is restricted (e.g. due to it being a primary key field). If set to false, silently skip any key where the setter method doesn‘t exist or access to it is restricted.
typecast_empty_string_to_nil  [RW]  Whether to typecast the empty string (’’) to nil for columns that are not string or blob. In most cases the empty string would be the way to specify a NULL SQL value in string form (nil.to_s == ’’), and an empty string would not usually be typecast correctly for other types, so the default is true.
typecast_on_assignment  [RW]  Whether to typecast attribute values on assignment (default: true). If set to false, no typecasting is done, so it will be left up to the database to typecast the value correctly.
use_transactions  [RW]  Whether to use a transaction by default when saving/deleting records (default: true). If you are sending database queries in before_* or after_* hooks, you shouldn‘t change the default setting without a good reason.

Public Instance methods

Returns the first record from the database matching the conditions. If a hash is given, it is used as the conditions. If another object is given, it finds the first record whose primary key(s) match the given argument(s). If no object is returned by the dataset, returns nil.

  Artist[1] # SELECT * FROM artists WHERE id = 1
  # => #<Artist {:id=>1, ...}>

  Artist[:name=>'Bob'] # SELECT * FROM artists WHERE (name = 'Bob') LIMIT 1
  # => #<Artist {:name=>'Bob', ...}>

[Source]

     # File lib/sequel/model/base.rb, line 104
104:       def [](*args)
105:         args = args.first if (args.size == 1)
106:         args.is_a?(Hash) ? dataset[args] : primary_key_lookup(args)
107:       end

Initializes a model instance as an existing record. This constructor is used by Sequel to initialize model instances when fetching records. Requires that values be a hash where all keys are symbols. It probably should not be used by external code.

[Source]

     # File lib/sequel/model/base.rb, line 113
113:       def call(values)
114:         o = allocate
115:         o.set_values(values)
116:         o.after_initialize
117:         o
118:       end

Clear the setter_methods cache

[Source]

     # File lib/sequel/model/base.rb, line 121
121:       def clear_setter_methods_cache
122:         @setter_methods = nil
123:       end

Returns the columns in the result set in their original order. Generally, this will use the columns determined via the database schema, but in certain cases (e.g. models that are based on a joined dataset) it will use Dataset#columns to find the columns.

  Artist.columns
  # => [:id, :name]

[Source]

     # File lib/sequel/model/base.rb, line 132
132:       def columns
133:         @columns || set_columns(dataset.naked.columns)
134:       end

Creates instance using new with the given values and block, and saves it.

  Artist.create(:name=>'Bob')
  # INSERT INTO artists (name) VALUES ('Bob')

  Artist.create do |a|
    a.name = 'Jim'
  end # INSERT INTO artists (name) VALUES ('Jim')

[Source]

     # File lib/sequel/model/base.rb, line 144
144:       def create(values = {}, &block)
145:         new(values, &block).save
146:       end

Returns the dataset associated with the Model class. Raises an Error if there is no associated dataset for this class. In most cases, you don‘t need to call this directly, as Model proxies many dataset methods to the underlying dataset.

  Artist.dataset.all # SELECT * FROM artists

[Source]

     # File lib/sequel/model/base.rb, line 154
154:       def dataset
155:         @dataset || raise(Error, "No dataset associated with #{self}")
156:       end

Alias of set_dataset

[Source]

     # File lib/sequel/model/base.rb, line 159
159:       def dataset=(ds)
160:         set_dataset(ds)
161:       end

Extend the dataset with a module, similar to adding a plugin with the methods defined in DatasetMethods. If a block is given, an anonymous module is created and the module_evaled, otherwise the argument should be a module. Returns the module given or the anonymous module created.

  Artist.dataset_module Sequel::ColumnsIntrospection

  Artist.dataset_module do
    def foo
      :bar
    end
  end
  Artist.dataset.foo
  # => :bar
  Artist.foo
  # => :bar

[Source]

     # File lib/sequel/model/base.rb, line 180
180:       def dataset_module(mod = nil)
181:         if mod
182:           raise Error, "can't provide both argument and block to Model.dataset_module" if block_given?
183:           dataset_extend(mod)
184:           mod
185:         else
186:           @dataset_module ||= Module.new
187:           @dataset_module.module_eval(&Proc.new) if block_given?
188:           dataset_extend(@dataset_module)
189:           @dataset_module
190:         end
191:       end

Returns the database associated with the Model class. If this model doesn‘t have a database associated with it, assumes the superclass‘s database, or the first object in Sequel::DATABASES. If no Sequel::Database object has been created, raises an error.

  Artist.db.transaction do # BEGIN
    Artist.create(:name=>'Bob')
    # INSERT INTO artists (name) VALUES ('Bob')
  end # COMMIT

[Source]

     # File lib/sequel/model/base.rb, line 203
203:       def db
204:         return @db if @db
205:         @db = self == Model ? DATABASES.first : superclass.db
206:         raise(Error, "No database associated with #{self}: have you called Sequel.connect or #{self}.db= ?") unless @db
207:         @db
208:       end

Sets the database associated with the Model class. If the model has an associated dataset, sets the model‘s dataset to a dataset on the new database with the same options used by the current dataset. This can be used directly on Sequel::Model to set the default database to be used by subclasses, or to override the database used for specific models:

  Sequel::Model.db = DB1
  Artist.db = DB2

[Source]

     # File lib/sequel/model/base.rb, line 220
220:       def db=(db)
221:         @db = db
222:         set_dataset(db.dataset(@dataset.opts)) if @dataset
223:       end

Returns the cached schema information if available or gets it from the database. This is a hash where keys are column symbols and values are hashes of information related to the column. See Database#schema.

  Artist.db_schema
  # {:id=>{:type=>:integer, :primary_key=>true, ...},
  #  :name=>{:type=>:string, :primary_key=>false, ...}}

[Source]

     # File lib/sequel/model/base.rb, line 233
233:       def db_schema
234:         @db_schema ||= get_db_schema
235:       end

Create a column alias, where the column methods have one name, but the underlying storage uses a different name.

[Source]

     # File lib/sequel/model/base.rb, line 239
239:       def def_column_alias(meth, column)
240:         clear_setter_methods_cache
241:         overridable_methods_module.module_eval do
242:           define_method(meth){self[column]}
243:           define_method("#{meth}="){|v| self[column] = v}
244:         end
245:       end

If a block is given, define a method on the dataset (if the model currently has an dataset) with the given argument name using the given block. Also define a class method on the model that calls the dataset method. Stores the method name and block so that it can be reapplied if the model‘s dataset changes.

If a block is not given, just define a class method on the model for each argument that calls the dataset method of the same argument name.

  # Add new dataset method and class method that calls it
  Artist.def_dataset_method(:by_name){order(:name)}
  Artist.filter(:name.like('A%')).by_name
  Artist.by_name.filter(:name.like('A%'))

  # Just add a class method that calls an existing dataset method
  Artist.def_dataset_method(:server!)
  Artist.server!(:server1)

[Source]

     # File lib/sequel/model/base.rb, line 263
263:       def def_dataset_method(*args, &block)
264:         raise(Error, "No arguments given") if args.empty?
265:         if block
266:           raise(Error, "Defining a dataset method using a block requires only one argument") if args.length > 1
267:           meth = args.first
268:           @dataset_methods[meth] = block
269:           dataset.meta_def(meth, &block) if @dataset
270:         end
271:         args.each do |arg|
272:           if arg.to_s =~ NORMAL_METHOD_NAME_REGEXP
273:             instance_eval("def #{arg}(*args, &block); dataset.#{arg}(*args, &block) end", __FILE__, __LINE__) unless respond_to?(arg, true)
274:           else
275:             def_model_dataset_method_block(arg)
276:           end
277:         end
278:       end

Finds a single record according to the supplied filter. You are encouraged to use Model.[] or Model.first instead of this method.

  Artist.find(:name=>'Bob')
  # SELECT * FROM artists WHERE (name = 'Bob') LIMIT 1

  Artist.find{name > 'M'}
  # SELECT * FROM artists WHERE (name > 'M') LIMIT 1

[Source]

     # File lib/sequel/model/base.rb, line 305
305:       def find(*args, &block)
306:         filter(*args, &block).first
307:       end

Like find but invokes create with given conditions when record does not exist. Unlike find in that the block used in this method is not passed to find, but instead is passed to create only if find does not return an object.

  Artist.find_or_create(:name=>'Bob')
  # SELECT * FROM artists WHERE (name = 'Bob') LIMIT 1
  # INSERT INTO artists (name) VALUES ('Bob')

  Artist.find_or_create(:name=>'Jim'){|a| a.hometown = 'Sactown'}
  # SELECT * FROM artists WHERE (name = 'Jim') LIMIT 1
  # INSERT INTO artists (name, hometown) VALUES ('Jim', 'Sactown')

[Source]

     # File lib/sequel/model/base.rb, line 321
321:       def find_or_create(cond, &block)
322:         find(cond) || create(cond, &block)
323:       end

Returns the implicit table name for the model class, which is the demodulized, underscored, pluralized name of the class.

  Artist.implicit_table_name # => :artists
  Foo::ArtistAlias.implicit_table_name # => :artist_aliases

[Source]

     # File lib/sequel/model/base.rb, line 371
371:       def implicit_table_name
372:         pluralize(underscore(demodulize(name))).to_sym
373:       end

Clear the setter_methods cache when a module is included, as it may contain setter methods.

[Source]

     # File lib/sequel/model/base.rb, line 327
327:       def include(mod)
328:         clear_setter_methods_cache
329:         super
330:       end

If possible, set the dataset for the model subclass as soon as it is created. Also, make sure the inherited class instance variables are copied into the subclass.

Sequel queries the database to get schema information as soon as a model class is created:

  class Artist < Sequel::Model # Causes schema query
  end

[Source]

     # File lib/sequel/model/base.rb, line 341
341:       def inherited(subclass)
342:         super
343:         ivs = subclass.instance_variables.collect{|x| x.to_s}
344:         EMPTY_INSTANCE_VARIABLES.each{|iv| subclass.instance_variable_set(iv, nil) unless ivs.include?(iv.to_s)}
345:         INHERITED_INSTANCE_VARIABLES.each do |iv, dup|
346:           next if ivs.include?(iv.to_s)
347:           sup_class_value = instance_variable_get(iv)
348:           sup_class_value = sup_class_value.dup if dup == :dup && sup_class_value
349:           subclass.instance_variable_set(iv, sup_class_value)
350:         end
351:         unless ivs.include?("@dataset")
352:           db
353:           begin
354:             if self == Model || !@dataset
355:               n = subclass.name
356:               subclass.set_dataset(subclass.implicit_table_name) unless n.nil? || n.empty?
357:             elsif @dataset
358:               subclass.set_dataset(@dataset.clone, :inherited=>true)
359:             end
360:           rescue
361:             nil
362:           end
363:         end
364:       end

Calls call with the values hash. Only for backwards compatibility.

[Source]

     # File lib/sequel/model/base.rb, line 376
376:       def load(values)
377:         call(values)
378:       end

Clear the setter_methods cache when a setter method is added

[Source]

     # File lib/sequel/model/base.rb, line 381
381:       def method_added(meth)
382:         clear_setter_methods_cache if meth.to_s =~ SETTER_METHOD_REGEXP
383:         super
384:       end

Mark the model as not having a primary key. Not having a primary key can cause issues, among which is that you won‘t be able to update records.

  Artist.primary_key # => :id
  Artist.no_primary_key
  Artist.primary_key # => nil

[Source]

     # File lib/sequel/model/base.rb, line 392
392:       def no_primary_key
393:         clear_setter_methods_cache
394:         @simple_pk = @primary_key = nil
395:       end

Loads a plugin for use with the model class, passing optional arguments to the plugin. If the plugin is a module, load it directly. Otherwise, require the plugin from either sequel/plugins/#{plugin} or sequel_#{plugin}, and then attempt to load the module using a the camelized plugin name under Sequel::Plugins.

[Source]

     # File lib/sequel/model/base.rb, line 402
402:       def plugin(plugin, *args, &blk)
403:         m = plugin.is_a?(Module) ? plugin : plugin_module(plugin)
404:         unless @plugins.include?(m)
405:           @plugins << m
406:           m.apply(self, *args, &blk) if m.respond_to?(:apply)
407:           include(m::InstanceMethods) if plugin_module_defined?(m, :InstanceMethods)
408:           extend(m::ClassMethods)if plugin_module_defined?(m, :ClassMethods)
409:           dataset_extend(m::DatasetMethods) if plugin_module_defined?(m, :DatasetMethods)
410:         end
411:         m.configure(self, *args, &blk) if m.respond_to?(:configure)
412:       end

Returns primary key attribute hash. If using a composite primary key value such be an array with values for each primary key in the correct order. For a standard primary key, value should be an object with a compatible type for the key. If the model does not have a primary key, raises an Error.

  Artist.primary_key_hash(1) # => {:id=>1}
  Artist.primary_key_hash([1, 2]) # => {:id1=>1, :id2=>2}

[Source]

     # File lib/sequel/model/base.rb, line 422
422:       def primary_key_hash(value)
423:         raise(Error, "#{self} does not have a primary key") unless key = @primary_key
424:         case key
425:         when Array
426:           hash = {}
427:           key.each_with_index{|k,i| hash[k] = value[i]}
428:           hash
429:         else
430:           {key => value}
431:         end
432:       end

Return a hash where the keys are qualified column references. Uses the given qualifier if provided, or the table_name otherwise. This is useful if you plan to join other tables to this table and you want the column references to be qualified.

  Artist.filter(Artist.qualified_primary_key_hash(1))
  # SELECT * FROM artists WHERE (artists.id = 1)

[Source]

     # File lib/sequel/model/base.rb, line 441
441:       def qualified_primary_key_hash(value, qualifier=table_name)
442:         h = primary_key_hash(value)
443:         h.to_a.each{|k,v| h[SQL::QualifiedIdentifier.new(qualifier, k)] = h.delete(k)}
444:         h
445:       end

Restrict the setting of the primary key(s) when using mass assignment (e.g. set). Because this is the default, this only make sense to use in a subclass where the parent class has used unrestrict_primary_key.

[Source]

     # File lib/sequel/model/base.rb, line 450
450:       def restrict_primary_key
451:         clear_setter_methods_cache
452:         @restrict_primary_key = true
453:       end

Whether or not setting the primary key(s) when using mass assignment (e.g. set) is restricted, true by default.

[Source]

     # File lib/sequel/model/base.rb, line 457
457:       def restrict_primary_key?
458:         @restrict_primary_key
459:       end

Set the columns to allow when using mass assignment (e.g. set). Using this means that any columns not listed here will not be modified. If you have any virtual setter methods (methods that end in =) that you want to be used during mass assignment, they need to be listed here as well (without the =).

It may be better to use a method such as set_only or set_fields that lets you specify the allowed fields per call.

  Artist.set_allowed_columns(:name, :hometown)
  Artist.set(:name=>'Bob', :hometown=>'Sactown') # No Error
  Artist.set(:name=>'Bob', :records_sold=>30000) # Error

[Source]

     # File lib/sequel/model/base.rb, line 472
472:       def set_allowed_columns(*cols)
473:         clear_setter_methods_cache
474:         @allowed_columns = cols
475:       end

Sets the dataset associated with the Model class. ds can be a Symbol, LiteralString, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression (all specifying a table name in the current database), or a Dataset. If a dataset is used, the model‘s database is changed to the database of the given dataset. If a dataset is not used, a dataset is created from the current database with the table name given. Other arguments raise an Error. Returns self.

This changes the row_proc of the dataset to return model objects, extends the dataset with the dataset_method_modules, and defines methods on the dataset using the dataset_methods. It also attempts to determine the database schema for the model, based on the given dataset.

  Artist.set_dataset(:tbl_artists)
  Artist.set_dataset(DB[:artists])

[Source]

     # File lib/sequel/model/base.rb, line 494
494:       def set_dataset(ds, opts={})
495:         inherited = opts[:inherited]
496:         @dataset = case ds
497:         when Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression, LiteralString
498:           @simple_table = db.literal(ds)
499:           db.from(ds)
500:         when Dataset
501:           @simple_table = if ds.send(:simple_select_all?)
502:             ds.literal(ds.first_source_table)
503:           else
504:             nil
505:           end
506:           @db = ds.db
507:           ds
508:         else
509:           raise(Error, "Model.set_dataset takes one of the following classes as an argument: Symbol, LiteralString, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression, Dataset")
510:         end
511:         @dataset.row_proc = self
512:         @require_modification = Sequel::Model.require_modification.nil? ? @dataset.provides_accurate_rows_matched? : Sequel::Model.require_modification
513:         if inherited
514:           @simple_table = superclass.simple_table
515:           @columns = @dataset.columns rescue nil
516:         else
517:           @dataset_method_modules.each{|m| @dataset.extend(m)} if @dataset_method_modules
518:           @dataset_methods.each{|meth, block| @dataset.meta_def(meth, &block)} if @dataset_methods
519:         end
520:         @dataset.model = self if @dataset.respond_to?(:model=)
521:         check_non_connection_error{@db_schema = (inherited ? superclass.db_schema : get_db_schema)}
522:         self
523:       end

Sets the primary key for this model. You can use either a regular or a composite primary key. To not use a primary key, set to nil or use no_primary_key. On most adapters, Sequel can automatically determine the primary key to use, so this method is not needed often.

  class Person < Sequel::Model
    # regular key
    set_primary_key :person_id
  end

  class Tagging < Sequel::Model
    # composite key
    set_primary_key [:taggable_id, :tag_id]
  end

[Source]

     # File lib/sequel/model/base.rb, line 539
539:       def set_primary_key(*key)
540:         clear_setter_methods_cache
541:         key = key.flatten
542:         @simple_pk = if key.length == 1
543:           (@dataset || db).literal(key.first)
544:         else 
545:           nil 
546:         end
547:         @primary_key = (key.length == 1) ? key[0] : key
548:       end

Set the columns to restrict when using mass assignment (e.g. set). Using this means that attempts to call setter methods for the columns listed here will cause an exception or be silently skipped (based on the strict_param_setting setting. If you have any virtual setter methods (methods that end in =) that you want not to be used during mass assignment, they need to be listed here as well (without the =).

It‘s generally a bad idea to rely on a blacklist approach for security. Using a whitelist approach such as set_allowed_columns or the instance level set_only or set_fields methods is usually a better choice. So use of this method is generally a bad idea.

  Artist.set_restricted_column(:records_sold)
  Artist.set(:name=>'Bob', :hometown=>'Sactown') # No Error
  Artist.set(:name=>'Bob', :records_sold=>30000) # Error

[Source]

     # File lib/sequel/model/base.rb, line 563
563:       def set_restricted_columns(*cols)
564:         clear_setter_methods_cache
565:         @restricted_columns = cols
566:       end

Cache of setter methods to allow by default, in order to speed up new/set/update instance methods.

[Source]

     # File lib/sequel/model/base.rb, line 569
569:       def setter_methods
570:         @setter_methods ||= if allowed_columns
571:           allowed_columns.map{|x| "#{x}="}
572:         else
573:           meths = instance_methods.collect{|x| x.to_s}.grep(SETTER_METHOD_REGEXP) - RESTRICTED_SETTER_METHODS
574:           meths -= Array(primary_key).map{|x| "#{x}="} if primary_key && restrict_primary_key?
575:           meths -= restricted_columns.map{|x| "#{x}="} if restricted_columns
576:           meths
577:         end
578:       end

Shortcut for def_dataset_method that is restricted to modifying the dataset‘s filter. Sometimes thought of as a scope, and like most dataset methods, they can be chained. For example:

  Topic.subset(:joes, :username.like('%joe%'))
  Topic.subset(:popular){num_posts > 100}
  Topic.subset(:recent){created_on > Date.today - 7}

Allows you to do:

  Topic.joes.recent.popular

to get topics with a username that includes joe that have more than 100 posts and were created less than 7 days ago.

Both the args given and the block are passed to Dataset#filter.

This method creates dataset methods that do not accept arguments. To create dataset methods that accept arguments, you have to use def_dataset_method.

[Source]

     # File lib/sequel/model/base.rb, line 601
601:       def subset(name, *args, &block)
602:         def_dataset_method(name){filter(*args, &block)}
603:       end

Returns name of primary table for the dataset. If the table for the dataset is aliased, returns the aliased name.

  Artist.table_name # => :artists
  Sequel::Model(:foo).table_name # => :foo
  Sequel::Model(:foo___bar).table_name # => :bar

[Source]

     # File lib/sequel/model/base.rb, line 611
611:       def table_name
612:         dataset.first_source_alias
613:       end

Allow the setting of the primary key(s) when using the mass assignment methods. Using this method can open up security issues, be very careful before using it.

  Artist.set(:id=>1) # Error
  Artist.unrestrict_primary_key
  Artist.set(:id=>1) # No Error

[Source]

     # File lib/sequel/model/base.rb, line 621
621:       def unrestrict_primary_key
622:         clear_setter_methods_cache
623:         @restrict_primary_key = false
624:       end

[Validate]