module Sequel::Plugins::SingleTableInheritance::ClassMethods

Attributes

sti_dataset[R]

The base dataset for STI, to which filters are added to get only the models for the specific STI subclass.

sti_key[R]

The column name holding the STI key for this model

sti_key_array[R]

Array holding keys for all subclasses of this class, used for the dataset filter in subclasses. Nil in the main class.

sti_key_chooser[R]

A proc which returns the value to use for new instances. This defaults to a lookup in the key map.

sti_key_map[R]

A hash/proc with class keys and column value values, mapping the class to a particular value given to the sti_key column. Used to set the column value when creating objects, and for the filter when retrieving objects in subclasses.

sti_model_map[R]

A hash/proc with column value keys and class values, mapping the value of the sti_key column to the appropriate class to use.

Public Instance Methods

freeze() click to toggle source

Freeze STI information when freezing model class. Note that because of how STI works, you should not freeze an STI subclass until after all subclasses of it have been created.

Calls superclass method
    # File lib/sequel/plugins/single_table_inheritance.rb
158 def freeze
159   @sti_key_array.freeze if @sti_key_array
160   @sti_key_map.freeze if @sti_key_map.is_a?(Hash)
161   @sti_model_map.freeze if @sti_model_map.is_a?(Hash)
162 
163   super
164 end
sti_class_from_sti_key(key) click to toggle source

Return the sti class based on one of the keys from sti_model_map.

    # File lib/sequel/plugins/single_table_inheritance.rb
173 def sti_class_from_sti_key(key)
174   sti_class(sti_model_map[key])
175 end
sti_load(r) click to toggle source

Return an instance of the class specified by sti_key, used by the row_proc.

    # File lib/sequel/plugins/single_table_inheritance.rb
168 def sti_load(r)
169   sti_class_from_sti_key(r[sti_key]).call(r)
170 end
sti_subclass_added(key) click to toggle source

Make sure that all subclasses of the parent class correctly include keys for all of their descendant classes.

    # File lib/sequel/plugins/single_table_inheritance.rb
179 def sti_subclass_added(key)
180   if sti_key_array
181     key_array = Array(key)
182     Sequel.synchronize{sti_key_array.push(*key_array)}
183     superclass.sti_subclass_added(key)
184   end
185 end

Private Instance Methods

dataset_extend(mod, opts=OPTS) click to toggle source

Extend the sti dataset with the module when extending the main dataset.

Calls superclass method
    # File lib/sequel/plugins/single_table_inheritance.rb
191 def dataset_extend(mod, opts=OPTS)
192   @sti_dataset = @sti_dataset.with_extend(mod)
193   super
194 end
inherited(subclass) click to toggle source

Copy the necessary attributes to the subclasses, and filter the subclass’s dataset based on the sti_kep_map entry for the class.

Calls superclass method
    # File lib/sequel/plugins/single_table_inheritance.rb
198 def inherited(subclass)
199   super
200   key = Array(sti_key_map[subclass]).dup
201   sti_subclass_added(key)
202   rp = dataset.row_proc
203   subclass.set_dataset(sti_subclass_dataset(key), :inherited=>true)
204   subclass.instance_exec do
205     @dataset = @dataset.with_row_proc(rp)
206     @sti_key_array = key
207     self.simple_table = nil
208   end
209 end
set_dataset_row_proc(ds) click to toggle source

If calling set_dataset manually, make sure to set the dataset row proc to one that handles inheritance correctly.

Calls superclass method
    # File lib/sequel/plugins/single_table_inheritance.rb
213 def set_dataset_row_proc(ds)
214   if @dataset
215     ds.with_row_proc(@dataset.row_proc)
216   else
217     super
218   end
219 end
sti_class(v) click to toggle source

Return a class object. If a class is given, return it directly. Treat strings and symbols as class names. If nil is given or an invalid class name string or symbol is used, return self. Raise an error for other types.

    # File lib/sequel/plugins/single_table_inheritance.rb
225 def sti_class(v)
226   case v
227   when String, Symbol
228     constantize(v) rescue self
229   when nil
230     self
231   when Class
232     v
233   else
234     raise(Error, "Invalid class type used: #{v.inspect}")
235   end
236 end
sti_subclass_dataset(key) click to toggle source

Use the given dataset for the subclass, with key being the allowed values for the sti_kind field.

    # File lib/sequel/plugins/single_table_inheritance.rb
240 def sti_subclass_dataset(key)
241   sti_dataset.where(SQL::QualifiedIdentifier.new(sti_dataset.first_source_alias, sti_key)=>Sequel.delay{Sequel.synchronize{key}})
242 end