Class: ActiveRecord::Associations::Association
- Inherits:
-
Object
- Object
- ActiveRecord::Associations::Association
- Defined in:
- lib/active_record/associations/association.rb
Overview
Active Record Associations
This is the root class of all associations (‘+ Foo’ signifies an included module Foo):
Association
SingularAssociation
HasOneAssociation
HasOneThroughAssociation + ThroughAssociation
BelongsToAssociation
BelongsToPolymorphicAssociation
CollectionAssociation
HasManyAssociation
HasManyThroughAssociation + ThroughAssociation
Direct Known Subclasses
Instance Attribute Summary collapse
-
#inversed ⇒ Object
Returns the value of attribute inversed.
-
#owner ⇒ Object
readonly
:nodoc:.
-
#reflection ⇒ Object
readonly
:nodoc:.
-
#target ⇒ Object
:nodoc:.
Instance Method Summary collapse
-
#aliased_table_name ⇒ Object
Returns the name of the table of the associated class:.
-
#association_scope ⇒ Object
The scope for this association.
-
#initialize(owner, reflection) ⇒ Association
constructor
A new instance of Association.
-
#initialize_attributes(record) ⇒ Object
:nodoc:.
- #interpolate(sql, record = nil) ⇒ Object
-
#klass ⇒ Object
Returns the class of the target.
-
#load_target ⇒ Object
Loads the target if needed and returns it.
-
#loaded! ⇒ Object
Asserts the target has been loaded setting the loaded flag to
true
. -
#loaded? ⇒ Boolean
Has the target been already loaded?.
-
#marshal_dump ⇒ Object
We can’t dump @reflection since it contains the scope proc.
- #marshal_load(data) ⇒ Object
-
#reload ⇒ Object
Reloads the target and returns
self
on success. -
#reset ⇒ Object
Resets the loaded flag to
false
and sets the target tonil
. - #reset_scope ⇒ Object
- #scope ⇒ Object
-
#set_inverse_instance(record) ⇒ Object
Set the inverse association, if possible.
-
#stale_target? ⇒ Boolean
The target is stale if the target no longer points to the record(s) that the relevant foreign_key(s) refers to.
-
#target_scope ⇒ Object
Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e. the through association’s scope).
Constructor Details
#initialize(owner, reflection) ⇒ Association
Returns a new instance of Association.
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# File 'lib/active_record/associations/association.rb', line 24 def initialize(owner, reflection) reflection.check_validity! @owner, @reflection = owner, reflection reset reset_scope end |
Instance Attribute Details
#inversed ⇒ Object
Returns the value of attribute inversed.
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# File 'lib/active_record/associations/association.rb', line 20 def inversed @inversed end |
#owner ⇒ Object (readonly)
:nodoc:
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# File 'lib/active_record/associations/association.rb', line 19 def owner @owner end |
#reflection ⇒ Object (readonly)
:nodoc:
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# File 'lib/active_record/associations/association.rb', line 19 def reflection @reflection end |
#target ⇒ Object
:nodoc:
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# File 'lib/active_record/associations/association.rb', line 19 def target @target end |
Instance Method Details
#aliased_table_name ⇒ Object
Returns the name of the table of the associated class:
post.comments.aliased_table_name # => "comments"
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# File 'lib/active_record/associations/association.rb', line 37 def aliased_table_name klass.table_name end |
#association_scope ⇒ Object
The scope for this association.
Note that the association_scope is merged into the target_scope only when the scope method is called. This is because at that point the call may be surrounded by scope.scoping { … } or with_scope { … } etc, which affects the scope which actually gets built.
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# File 'lib/active_record/associations/association.rb', line 95 def association_scope if klass @association_scope ||= AssociationScope.scope(self, klass.connection) end end |
#initialize_attributes(record) ⇒ Object
:nodoc:
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# File 'lib/active_record/associations/association.rb', line 166 def initialize_attributes(record) #:nodoc: skip_assign = [reflection.foreign_key, reflection.type].compact attributes = create_scope.except(*(record.changed - skip_assign)) record.assign_attributes(attributes) set_inverse_instance(record) end |
#interpolate(sql, record = nil) ⇒ Object
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# File 'lib/active_record/associations/association.rb', line 146 def interpolate(sql, record = nil) if sql.respond_to?(:to_proc) owner.instance_exec(record, &sql) else sql end end |
#klass ⇒ Object
Returns the class of the target. belongs_to polymorphic overrides this to look at the polymorphic_type field on the owner.
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# File 'lib/active_record/associations/association.rb', line 117 def klass reflection.klass end |
#load_target ⇒ Object
Loads the target if needed and returns it.
This method is abstract in the sense that it relies on find_target
, which is expected to be provided by descendants.
If the target is already loaded it is just returned. Thus, you can call load_target
unconditionally to get the target.
ActiveRecord::RecordNotFound is rescued within the method, and it is not reraised. The proxy is reset and nil
is the return value.
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# File 'lib/active_record/associations/association.rb', line 137 def load_target @target = find_target if (@stale_state && stale_target?) || find_target? loaded! unless loaded? target rescue ActiveRecord::RecordNotFound reset end |
#loaded! ⇒ Object
Asserts the target has been loaded setting the loaded flag to true
.
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# File 'lib/active_record/associations/association.rb', line 63 def loaded! @loaded = true @stale_state = stale_state @inversed = false end |
#loaded? ⇒ Boolean
Has the target been already loaded?
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# File 'lib/active_record/associations/association.rb', line 58 def loaded? @loaded end |
#marshal_dump ⇒ Object
We can’t dump @reflection since it contains the scope proc
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# File 'lib/active_record/associations/association.rb', line 155 def marshal_dump ivars = (instance_variables - [:@reflection]).map { |name| [name, instance_variable_get(name)] } [@reflection.name, ivars] end |
#marshal_load(data) ⇒ Object
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# File 'lib/active_record/associations/association.rb', line 160 def marshal_load(data) reflection_name, ivars = data ivars.each { |name, val| instance_variable_set(name, val) } @reflection = @owner.class._reflect_on_association(reflection_name) end |
#reload ⇒ Object
Reloads the target and returns self
on success.
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# File 'lib/active_record/associations/association.rb', line 50 def reload reset reset_scope load_target self unless target.nil? end |
#reset ⇒ Object
Resets the loaded flag to false
and sets the target to nil
.
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# File 'lib/active_record/associations/association.rb', line 42 def reset @loaded = false @target = nil @stale_state = nil @inversed = false end |
#reset_scope ⇒ Object
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# File 'lib/active_record/associations/association.rb', line 101 def reset_scope @association_scope = nil end |
#scope ⇒ Object
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# File 'lib/active_record/associations/association.rb', line 85 def scope target_scope.merge(association_scope) end |
#set_inverse_instance(record) ⇒ Object
Set the inverse association, if possible
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# File 'lib/active_record/associations/association.rb', line 106 def set_inverse_instance(record) if invertible_for?(record) inverse = record.association(inverse_reflection_for(record).name) inverse.target = owner inverse.inversed = true end record end |
#stale_target? ⇒ Boolean
The target is stale if the target no longer points to the record(s) that the relevant foreign_key(s) refers to. If stale, the association accessor method on the owner will reload the target. It’s up to subclasses to implement the stale_state method if relevant.
Note that if the target has not been loaded, it is not considered stale.
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# File 'lib/active_record/associations/association.rb', line 75 def stale_target? !inversed && loaded? && @stale_state != stale_state end |
#target_scope ⇒ Object
Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e. the through association’s scope)
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# File 'lib/active_record/associations/association.rb', line 123 def target_scope AssociationRelation.create(klass, klass.arel_table, self).merge!(klass.all) end |