Module: Cequel::Record::Associations::ClassMethods

Includes:
Forwardable
Defined in:
lib/cequel/record/associations.rb

Overview

Class macros for declaring associations

See Also:

Since:

  • 1.0.0

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#child_associations ⇒ Hash<Symbol,HasManyAssociation>

Returns associations declared by #has_many.

Returns:




# File 'lib/cequel/record/associations.rb', line 69

#parent_association ⇒ BelongsToAssociation

Returns association declared by #belongs_to.

Returns:




# File 'lib/cequel/record/associations.rb', line 69

Instance Method Details

#belongs_to(name, options = {}) ⇒ void

This method returns an undefined value.

Declare the parent association for this record. The name of the class is inferred from the name of the association. The belongs_to declaration also serves to define key columns, which are derived from the key columns of the parent class. So, if the parent class Blog has a primary key ‘(subdomain)`, this will declare a key column blog_subdomain of the same type.

Parent associations are read/write, so declaring ‘belongs_to :blog` will define a blog getter and blog= setter, which will update the underlying key column. Note that a record’s parent cannot be changed once the record has been saved.

Parameters:

  • name (Symbol) —

    name of the parent association

  • options (Options) (defaults to: {}) —

    options for association

Options Hash (options):

  • :class_name (String) —

    name of parent class

See Also:

Since:

  • 1.0.0



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# File 'lib/cequel/record/associations.rb', line 96

def belongs_to(name, options = {})
  if parent_association
    fail InvalidRecordConfiguration,
         "Can't declare more than one belongs_to association"
  end
  if table_schema.key_columns.any?
    fail InvalidRecordConfiguration,
         "belongs_to association must be declared before declaring " \
         "key(s)"
  end

  self.parent_association =
    BelongsToAssociation.new(self, name.to_sym, options)

  parent_association.association_key_columns.each do |column|
    key :"#{name}_#{column.name}", column.type
  end
  def_parent_association_accessors
end

#has_many(name, options = {}) ⇒ void

This method returns an undefined value.

Declare a child association. The child association should have a belongs_to referencing this class or, at a minimum, must have a primary key whose first N columns have the same types as the N columns in this class’s primary key.

has_many associations are read-only, so ‘has_many :posts` will define a posts reader but not a posts= writer; and the collection returned by posts will be immutable.

Parameters:

  • name (Symbol) —

    plural name of association

  • options (Options) (defaults to: {}) —

    options for association

Options Hash (options):

  • :class_name (Symbol) —

    name of the child class

  • :dependent (Boolean) —

    propagation behavior for destroy

See Also:

Since:

  • 1.0.0



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# File 'lib/cequel/record/associations.rb', line 133

def has_many(name, options = {})
  association = HasManyAssociation.new(self, name.to_sym, options)
  self.child_associations =
    child_associations.merge(name => association)
  def_child_association_reader(association)
end