module ActiveRecord::AttributeMethods::CompositePrimaryKey

def id

returns an array of the primary key column values.
Returns the primary key column's value. If the primary key is composite,
:nodoc:

def id
  if self.class.composite_primary_key?
    @primary_key.map { |pk| _read_attribute(pk) }
  else
    super
  end
end

def id=(value)

raises TypeError when the set value not enumerable.
Sets the primary key column's value. If the primary key is composite,

def id=(value)
  if self.class.composite_primary_key?
    raise TypeError, "Expected value matching #{self.class.primary_key.inspect}, got #{value.inspect}." unless value.is_a?(Enumerable)
    @primary_key.zip(value) { |attr, value| _write_attribute(attr, value) }
  else
    super
  end
end

def id?

all primary key column values must be queryable.
Queries the primary key column's value. If the primary key is composite,

def id?
  if self.class.composite_primary_key?
    @primary_key.all? { |col| _query_attribute(col) }
  else
    super
  end
end

def id_before_type_cast

returns an array of primary key column values before type cast.
Returns the primary key column's value before type cast. If the primary key is composite,

def id_before_type_cast
  if self.class.composite_primary_key?
    @primary_key.map { |col| attribute_before_type_cast(col) }
  else
    super
  end
end

def id_for_database # :nodoc:

:nodoc:

def id_for_database # :nodoc:
  if self.class.composite_primary_key?
    @primary_key.map { |col| @attributes[col].value_for_database }
  else
    super
  end
end

def id_in_database

returns an array of primary key column values from database.
Returns the primary key column's value from the database. If the primary key is composite,

def id_in_database
  if self.class.composite_primary_key?
    @primary_key.map { |col| attribute_in_database(col) }
  else
    super
  end
end

def id_was

returns an array of primary key column previous values.
Returns the primary key column's previous value. If the primary key is composite,

def id_was
  if self.class.composite_primary_key?
    @primary_key.map { |col| attribute_was(col) }
  else
    super
  end
end

def primary_key_values_present? # :nodoc: