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.
default_set_fields_options  [RW]  The default options to use for Model#set_fields. These are merged with the options given to set_fields.
fast_instance_delete_sql  [R]  SQL string fragment used for faster DELETE statement creation when deleting/destroying model instances, or nil if the optimization should not be used. For internal use only.
instance_dataset  [R]  The dataset that instance datasets (this) are based on. Generally a naked version of the model‘s dataset limited to one row. For internal use only.
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_schema_types validation (from the validation_helpers plugin) in connection with this setting to check for typecast failures during validation.
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).
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_after_commit_rollback  [RW]  Whether to enable the after_commit and after_rollback hooks when saving/destroying instances. On by default, can be turned off for performance reasons or when using prepared transactions (which aren‘t compatible with after commit/rollback).
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 108
108:       def [](*args)
109:         args = args.first if args.size <= 1
110:         args.is_a?(Hash) ? dataset[args] : (primary_key_lookup(args) unless args.nil?)
111:       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 117
117:       def call(values)
118:         o = allocate
119:         o.instance_variable_set(:@values, values)
120:         o
121:       end

Clear the setter_methods cache

[Source]

     # File lib/sequel/model/base.rb, line 124
124:       def clear_setter_methods_cache
125:         @setter_methods = nil
126:       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 135
135:       def columns
136:         @columns || set_columns(dataset.naked.columns)
137:       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 147
147:       def create(values = {}, &block)
148:         new(values, &block).save
149:       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 157
157:       def dataset
158:         @dataset || raise(Error, "No dataset associated with #{self}")
159:       end

Alias of set_dataset

[Source]

     # File lib/sequel/model/base.rb, line 162
162:       def dataset=(ds)
163:         set_dataset(ds)
164:       end

Extend the dataset with a module, similar to adding a plugin with the methods defined in DatasetMethods. This is the recommended way to add methods to model datasets.

If an argument, it should be a module, and is used to extend the underlying dataset. Otherwise an anonymous module is created, and if a block is given, it is module_evaled, allowing you do define dataset methods directly using the standard ruby def syntax. Returns the module given or the anonymous module created.

  # Usage with existing module
  Artist.dataset_module Sequel::ColumnsIntrospection

  # Usage with anonymous module
  Artist.dataset_module do
    def foo
      :bar
    end
  end
  Artist.dataset.foo
  # => :bar
  Artist.foo
  # => :bar

Any anonymous modules created are actually instances of Sequel::Model::DatasetModule (a Module subclass), which allows you to call the subset method on them:

  Artist.dataset_module do
    subset :released, Sequel.identifier(release_date) > Sequel::CURRENT_DATE
  end

Any public methods in the dataset module will have class methods created that call the method on the dataset, assuming that the class method is not already defined.

[Source]

     # File lib/sequel/model/base.rb, line 200
200:       def dataset_module(mod = nil)
201:         if mod
202:           raise Error, "can't provide both argument and block to Model.dataset_module" if block_given?
203:           dataset_extend(mod)
204:           mod
205:         else
206:           @dataset_module ||= DatasetModule.new(self)
207:           @dataset_module.module_eval(&Proc.new) if block_given?
208:           dataset_extend(@dataset_module)
209:           @dataset_module
210:         end
211:       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 223
223:       def db
224:         return @db if @db
225:         @db = self == Model ? Sequel.synchronize{DATABASES.first} : superclass.db
226:         raise(Error, "No database associated with #{self}: have you called Sequel.connect or #{self}.db= ?") unless @db
227:         @db
228:       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

Note that you should not use this to change the model‘s database at runtime. If you have that need, you should look into Sequel‘s sharding support.

[Source]

     # File lib/sequel/model/base.rb, line 244
244:       def db=(db)
245:         @db = db
246:         set_dataset(db.dataset.clone(@dataset.opts)) if @dataset
247:       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 257
257:       def db_schema
258:         @db_schema ||= get_db_schema
259:       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 263
263:       def def_column_alias(meth, column)
264:         clear_setter_methods_cache
265:         overridable_methods_module.module_eval do
266:           define_method(meth){self[column]}
267:           define_method("#{meth}="){|v| self[column] = v}
268:         end
269:       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.

It is recommended that you define methods inside a block passed to dataset_module instead of using this method, as dataset_module allows you to use normal ruby def syntax.

  # 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 291
291:       def def_dataset_method(*args, &block)
292:         raise(Error, "No arguments given") if args.empty?
293: 
294:         if block
295:           raise(Error, "Defining a dataset method using a block requires only one argument") if args.length > 1
296:           dataset_module{define_method(args.first, &block)}
297:         else
298:           args.each{|arg| def_model_dataset_method(arg)}
299:         end
300:       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 310
310:       def find(*args, &block)
311:         filter(*args, &block).first
312:       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 326
326:       def find_or_create(cond, &block)
327:         find(cond) || create(cond, &block)
328:       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 385
385:       def implicit_table_name
386:         pluralize(underscore(demodulize(name))).to_sym
387:       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 332
332:       def include(mod)
333:         clear_setter_methods_cache
334:         super
335:       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 346
346:       def inherited(subclass)
347:         super
348:         ivs = subclass.instance_variables.collect{|x| x.to_s}
349:         inherited_instance_variables.each do |iv, dup|
350:           next if ivs.include?(iv.to_s)
351:           if (sup_class_value = instance_variable_get(iv)) && dup
352:             sup_class_value = case dup
353:             when :dup
354:               sup_class_value.dup
355:             when :hash_dup
356:               h = {}
357:               sup_class_value.each{|k,v| h[k] = v.dup}
358:               h
359:             when Proc
360:               dup.call(sup_class_value)
361:             else
362:               raise Error, "bad inherited instance variable type: #{dup.inspect}"
363:             end
364:           end
365:           subclass.instance_variable_set(iv, sup_class_value)
366:         end
367:         unless ivs.include?("@dataset")
368:           if self == Model || !@dataset
369:             n = subclass.name
370:             unless n.nil? || n.empty?
371:               db
372:               subclass.set_dataset(subclass.implicit_table_name) rescue nil
373:             end
374:           elsif @dataset
375:             subclass.set_dataset(@dataset.clone, :inherited=>true) rescue nil
376:           end
377:         end
378:       end

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

[Source]

     # File lib/sequel/model/base.rb, line 390
390:       def load(values)
391:         call(values)
392:       end

Clear the setter_methods cache when a setter method is added

[Source]

     # File lib/sequel/model/base.rb, line 395
395:       def method_added(meth)
396:         clear_setter_methods_cache if meth.to_s =~ SETTER_METHOD_REGEXP
397:         super
398:       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 406
406:       def no_primary_key
407:         clear_setter_methods_cache
408:         self.simple_pk = @primary_key = nil
409:       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 416
416:       def plugin(plugin, *args, &block)
417:         m = plugin.is_a?(Module) ? plugin : plugin_module(plugin)
418:         unless @plugins.include?(m)
419:           @plugins << m
420:           m.apply(self, *args, &block) if m.respond_to?(:apply)
421:           extend(m::ClassMethods) if plugin_module_defined?(m, :ClassMethods)
422:           include(m::InstanceMethods) if plugin_module_defined?(m, :InstanceMethods)
423:           if plugin_module_defined?(m, :DatasetMethods)
424:             dataset_extend(m::DatasetMethods, :create_class_methods=>false)
425:           end
426:         end
427:         m.configure(self, *args, &block) if m.respond_to?(:configure)
428:       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 438
438:       def primary_key_hash(value)
439:         raise(Error, "#{self} does not have a primary key") unless key = @primary_key
440:         case key
441:         when Array
442:           hash = {}
443:           key.each_with_index{|k,i| hash[k] = value[i]}
444:           hash
445:         else
446:           {key => value}
447:         end
448:       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 457
457:       def qualified_primary_key_hash(value, qualifier=table_name)
458:         h = primary_key_hash(value)
459:         h.to_a.each{|k,v| h[SQL::QualifiedIdentifier.new(qualifier, k)] = h.delete(k)}
460:         h
461:       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 466
466:       def restrict_primary_key
467:         clear_setter_methods_cache
468:         @restrict_primary_key = true
469:       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 473
473:       def restrict_primary_key?
474:         @restrict_primary_key
475:       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 488
488:       def set_allowed_columns(*cols)
489:         clear_setter_methods_cache
490:         @allowed_columns = cols
491:       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 and extends the dataset with the dataset_method_modules. 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])

Note that you should not use this to change the model‘s dataset at runtime. If you have that need, you should look into Sequel‘s sharding support.

[Source]

     # File lib/sequel/model/base.rb, line 513
513:       def set_dataset(ds, opts=OPTS)
514:         inherited = opts[:inherited]
515:         case ds
516:         when Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression, LiteralString
517:           self.simple_table = db.literal(ds)
518:           ds = db.from(ds)
519:         when Dataset
520:           self.simple_table = if ds.send(:simple_select_all?)
521:             ds.literal(ds.first_source_table)
522:           else
523:             nil
524:           end
525:           @db = ds.db
526:         else
527:           raise(Error, "Model.set_dataset takes one of the following classes as an argument: Symbol, LiteralString, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression, Dataset")
528:         end
529:         set_dataset_row_proc(ds)
530:         @dataset = ds
531:         @require_modification = Sequel::Model.require_modification.nil? ? @dataset.provides_accurate_rows_matched? : Sequel::Model.require_modification
532:         if inherited
533:           self.simple_table = superclass.simple_table
534:           @columns = @dataset.columns rescue nil
535:         else
536:           @dataset_method_modules.each{|m| @dataset.extend(m)} if @dataset_method_modules
537:         end
538:         @dataset.model = self if @dataset.respond_to?(:model=)
539:         check_non_connection_error{@db_schema = (inherited ? superclass.db_schema : get_db_schema)}
540:         reset_instance_dataset
541:         self
542:       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 558
558:       def set_primary_key(key)
559:         clear_setter_methods_cache
560:         if key.is_a?(Array) && key.length < 2
561:           key = key.first
562:         end
563:         self.simple_pk = if key && !key.is_a?(Array)
564:           (@dataset || db).literal(key)
565:         end
566:         @primary_key = key
567:       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 570
570:       def setter_methods
571:         @setter_methods ||= get_setter_methods
572:       end

Sets up a dataset method that returns a filtered dataset. 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 should use define a method directly inside a dataset_module block.

[Source]

     # File lib/sequel/model/base.rb, line 596
596:       def subset(name, *args, &block)
597:         dataset_module.subset(name, *args, &block)
598:       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 606
606:       def table_name
607:         dataset.first_source_alias
608:       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 616
616:       def unrestrict_primary_key
617:         clear_setter_methods_cache
618:         @restrict_primary_key = false
619:       end

Return the model instance with the primary key, or nil if there is no matching record.

[Source]

     # File lib/sequel/model/base.rb, line 622
622:       def with_pk(pk)
623:         primary_key_lookup(pk)
624:       end

Return the model instance with the primary key, or raise NoMatchingRow if there is no matching record.

[Source]

     # File lib/sequel/model/base.rb, line 627
627:       def with_pk!(pk)
628:         with_pk(pk) || raise(NoMatchingRow)
629:       end

[Validate]