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

[] call clear_setter_methods_cache columns create dataset dataset= dataset_module db db= db_schema def_column_alias def_dataset_method find find_or_create implicit_table_name include inherited load method_added no_primary_key plugin primary_key_hash qualified_primary_key_hash restrict_primary_key restrict_primary_key? set_allowed_columns set_dataset set_primary_key set_restricted_columns setter_methods subset table_name unrestrict_primary_key

### 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).
cache_anonymous_models | [RW] | Whether to cache the anonymous models created by Sequel::Model(). This is required for reloading them correctly (avoiding the superclass mismatch). True by default for backwards compatibility.
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.
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_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_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

[](*args)

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 122
    122:       def [](*args)
    123:         args = args.first if args.size <= 1
    124:         args.is_a?(Hash) ? dataset[args] : (primary_key_lookup(args) unless args.nil?)
    125:       end

call(values)

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 131
    131:       def call(values)
    132:         o = allocate
    133:         o.set_values(values)
    134:         o.after_initialize
    135:         o
    136:       end

clear_setter_methods_cache()

Clear the setter_methods cache

[Source]

         # File lib/sequel/model/base.rb, line 139
    139:       def clear_setter_methods_cache
    140:         @setter_methods = nil
    141:       end

columns()

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 150
    150:       def columns
    151:         @columns || set_columns(dataset.naked.columns)
    152:       end

create(values = {}, &block)

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 162
    162:       def create(values = {}, &block)
    163:         new(values, &block).save
    164:       end

dataset()

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 172
    172:       def dataset
    173:         @dataset || raise(Error, "No dataset associated with #{self}")
    174:       end

dataset=(ds)

Alias of set_dataset

[Source]

         # File lib/sequel/model/base.rb, line 177
    177:       def dataset=(ds)
    178:         set_dataset(ds)
    179:       end

dataset_module(mod = nil)

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 198
    198:       def dataset_module(mod = nil)
    199:         if mod
    200:           raise Error, "can't provide both argument and block to Model.dataset_module" if block_given?
    201:           dataset_extend(mod)
    202:           mod
    203:         else
    204:           @dataset_module ||= Module.new
    205:           @dataset_module.module_eval(&Proc.new) if block_given?
    206:           dataset_extend(@dataset_module)
    207:           @dataset_module
    208:         end
    209:       end

db()

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 221
    221:       def db
    222:         return @db if @db
    223:         @db = self == Model ? Sequel.synchronize{DATABASES.first} : superclass.db
    224:         raise(Error, "No database associated with #{self}: have you called Sequel.connect or #{self}.db= ?") unless @db
    225:         @db
    226:       end

db=(db)

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 238
    238:       def db=(db)
    239:         @db = db
    240:         set_dataset(db.dataset(@dataset.opts)) if @dataset
    241:       end

db_schema()

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 251
    251:       def db_schema
    252:         @db_schema ||= get_db_schema
    253:       end

def_column_alias(meth, column)

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 257
    257:       def def_column_alias(meth, column)
    258:         clear_setter_methods_cache
    259:         overridable_methods_module.module_eval do
    260:           define_method(meth){self[column]}
    261:           define_method("#{meth}="){|v| self[column] = v}
    262:         end
    263:       end

def_dataset_method(*args, &block)

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 281
    281:       def def_dataset_method(*args, &block)
    282:         raise(Error, "No arguments given") if args.empty?
    283:         if block
    284:           raise(Error, "Defining a dataset method using a block requires only one argument") if args.length > 1
    285:           meth = args.first
    286:           @dataset_methods[meth] = block
    287:           dataset.meta_def(meth, &block) if @dataset
    288:         end
    289:         args.each do |arg|
    290:           if arg.to_s =~ NORMAL_METHOD_NAME_REGEXP
    291:             instance_eval("def #{arg}(*args, &block); dataset.#{arg}(*args, &block) end", __FILE__, __LINE__) unless respond_to?(arg, true)
    292:           else
    293:             def_model_dataset_method_block(arg)
    294:           end
    295:         end
    296:       end

find(*args, &block)

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 306
    306:       def find(*args, &block)
    307:         filter(*args, &block).first
    308:       end

find_or_create(cond, &block)

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 322
    322:       def find_or_create(cond, &block)
    323:         find(cond) || create(cond, &block)
    324:       end

implicit_table_name()

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 370
    370:       def implicit_table_name
    371:         pluralize(underscore(demodulize(name))).to_sym
    372:       end

include(mod)

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

[Source]

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

inherited(subclass)

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

load(values)

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

[Source]

         # File lib/sequel/model/base.rb, line 375
    375:       def load(values)
    376:         call(values)
    377:       end

method_added(meth)

Clear the setter_methods cache when a setter method is added

[Source]

         # File lib/sequel/model/base.rb, line 380
    380:       def method_added(meth)
    381:         clear_setter_methods_cache if meth.to_s =~ SETTER_METHOD_REGEXP
    382:         super
    383:       end

no_primary_key()

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 391
    391:       def no_primary_key
    392:         clear_setter_methods_cache
    393:         self.simple_pk = @primary_key = nil
    394:       end

plugin(plugin, *args, &block)

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 401
    401:       def plugin(plugin, *args, &block)
    402:         m = plugin.is_a?(Module) ? plugin : plugin_module(plugin)
    403:         unless @plugins.include?(m)
    404:           @plugins << m
    405:           m.apply(self, *args, &block) if m.respond_to?(:apply)
    406:           include(m::InstanceMethods) if plugin_module_defined?(m, :InstanceMethods)
    407:           extend(m::ClassMethods)if plugin_module_defined?(m, :ClassMethods)
    408:           dataset_extend(m::DatasetMethods) if plugin_module_defined?(m, :DatasetMethods)
    409:         end
    410:         m.configure(self, *args, &block) if m.respond_to?(:configure)
    411:       end

primary_key_hash(value)

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 421
    421:       def primary_key_hash(value)
    422:         raise(Error, "#{self} does not have a primary key") unless key = @primary_key
    423:         case key
    424:         when Array
    425:           hash = {}
    426:           key.each_with_index{|k,i| hash[k] = value[i]}
    427:           hash
    428:         else
    429:           {key => value}
    430:         end
    431:       end

qualified_primary_key_hash(value, qualifier=table_name)

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 440
    440:       def qualified_primary_key_hash(value, qualifier=table_name)
    441:         h = primary_key_hash(value)
    442:         h.to_a.each{|k,v| h[SQL::QualifiedIdentifier.new(qualifier, k)] = h.delete(k)}
    443:         h
    444:       end

restrict_primary_key()

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 449
    449:       def restrict_primary_key
    450:         clear_setter_methods_cache
    451:         @restrict_primary_key = true
    452:       end

restrict_primary_key?()

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 456
    456:       def restrict_primary_key?
    457:         @restrict_primary_key
    458:       end

set_allowed_columns(*cols)

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 471
    471:       def set_allowed_columns(*cols)
    472:         clear_setter_methods_cache
    473:         @allowed_columns = cols
    474:       end

set_dataset(ds, opts={})

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 493
    493:       def set_dataset(ds, opts={})
    494:         inherited = opts[:inherited]
    495:         @dataset = case ds
    496:         when Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression, LiteralString
    497:           self.simple_table = db.literal(ds)
    498:           db.from(ds)
    499:         when Dataset
    500:           self.simple_table = if ds.send(:simple_select_all?)
    501:             ds.literal(ds.first_source_table)
    502:           else
    503:             nil
    504:           end
    505:           @db = ds.db
    506:           ds
    507:         else
    508:           raise(Error, "Model.set_dataset takes one of the following classes as an argument: Symbol, LiteralString, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression, Dataset")
    509:         end
    510:         @dataset.row_proc = self
    511:         @require_modification = Sequel::Model.require_modification.nil? ? @dataset.provides_accurate_rows_matched? : Sequel::Model.require_modification
    512:         if inherited
    513:           self.simple_table = superclass.simple_table
    514:           @columns = @dataset.columns rescue nil
    515:         else
    516:           @dataset_method_modules.each{|m| @dataset.extend(m)} if @dataset_method_modules
    517:           @dataset_methods.each{|meth, block| @dataset.meta_def(meth, &block)} if @dataset_methods
    518:         end
    519:         @dataset.model = self if @dataset.respond_to?(:model=)
    520:         check_non_connection_error{@db_schema = (inherited ? superclass.db_schema : get_db_schema)}
    521:         @instance_dataset = @dataset.limit(1).naked
    522:         self
    523:       end

set_primary_key(*key)

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:         self.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_restricted_columns(*cols)

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

setter_methods()

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

subset(name, *args, &block)

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

table_name()

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

unrestrict_primary_key()

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]