set_source_expressions(expressions) Takes a list of expressions and stores them such that get_source_expressions() can return them.

reverse_ordering() Returns self with any modifications required to reverse the sort order within an order_by call. As an example, an expression implementing NULLS LAST would change its value to be NULLS FIRST. Modifications are only required for expressions that implement sort order like OrderBy. This method is called when reverse() is called on a queryset.

get_source_expressions() Returns an ordered list of inner expressions. For example: >>> Sum(F('foo')).get_source_expressions() [F('foo')]

resolve_expression(query=None, allow_joins=True, reuse=None, summarize=False, for_save=False) Provides the chance to do any pre-processing or validation of the expression before it’s added to the query. resolve_expression() must also be called on any nested expressions. A copy() of self should be returned with any necessary transformations. query is the backend query implementation. allow_joins is a boolean that allows or denies the use of joins in the query. reuse is a set of reusable joins

desc() Returns the expression ready to be sorted in descending order.

class EmailField(max_length=254, **options) [source] A CharField that checks that the value is a valid email address. It uses EmailValidator to validate the input.

contains_aggregate Tells Django that this expression contains an aggregate and that a GROUP BY clause needs to be added to the query.

class Expression [source] contains_aggregate Tells Django that this expression contains an aggregate and that a GROUP BY clause needs to be added to the query. resolve_expression(query=None, allow_joins=True, reuse=None, summarize=False, for_save=False) Provides the chance to do any pre-processing or validation of the expression before it’s added to the query. resolve_expression() must also be called on any nested expressions. A copy() of self should be returned with any necessary t

asc() Returns the expression ready to be sorted in ascending order.

convert_value(self, value, expression, connection, context) A hook allowing the expression to coerce value into a more appropriate type.