Method: Sequel::Model::Associations::DatasetMethods#complex_expression_sql_append

Defined in:

lib/sequel/model/associations.rb

#complex_expression_sql_append(sql, op, args) ⇒ Object

If the expression is in the form x = y where y is a Sequel::Model instance, array of Sequel::Model instances, or a Sequel::Model dataset, assume x is an association symbol and look up the association reflection via the dataset’s model. From there, return the appropriate SQL based on the type of association and the values of the foreign/primary keys of y. For most association types, this is a simple transformation, but for many_to_many associations this creates a subquery to the join table.

# File 'lib/sequel/model/associations.rb', line 3061

def complex_expression_sql_append(sql, op, args)
  r = args[1]
  if (((op == :'=' || op == :'!=') && r.is_a?(Sequel::Model)) ||
      (multiple = ((op == :IN || op == :'NOT IN') && ((is_ds = r.is_a?(Sequel::Dataset)) || (r.respond_to?(:all?) && r.all?{|x| x.is_a?(Sequel::Model)})))))
    l = args[0]
    if ar = model.association_reflections[l]
      raise Error, "filtering by associations is not allowed for #{ar.inspect}" if ar[:allow_filtering_by] == false

      if multiple
        klass = ar.associated_class
        if is_ds
          if r.respond_to?(:model)
            unless r.model <= klass
              # A dataset for a different model class, could be a valid regular query
              return super
            end
          else
            # Not a model dataset, could be a valid regular query
            return super
          end
        else
          unless r.all?{|x| x.is_a?(klass)}
            raise Sequel::Error, "invalid association class for one object for association #{l.inspect} used in dataset filter for model #{model.inspect}, expected class #{klass.inspect}"
          end
        end
      elsif !r.is_a?(ar.associated_class)
        raise Sequel::Error, "invalid association class #{r.class.inspect} for association #{l.inspect} used in dataset filter for model #{model.inspect}, expected class #{ar.associated_class.inspect}"
      end

      if exp = association_filter_expression(op, ar, r)
        literal_append(sql, exp)
      else
        raise Sequel::Error, "invalid association type #{ar[:type].inspect} for association #{l.inspect} used in dataset filter for model #{model.inspect}"
      end
    elsif multiple && (is_ds || r.empty?)
      # Not a query designed for this support, could be a valid regular query
      super
    else
      raise Sequel::Error, "invalid association #{l.inspect} used in dataset filter for model #{model.inspect}"
    end
  else
    super
  end
end