django.db.models.sql.datastructures

module documentation

(source)

Useful auxiliary data structures for query construction. Not useful outside the SQL domain.

Class	`BaseTable`	The BaseTable class is used for base table references in FROM clause. For example, the SQL "foo" in SELECT * FROM "foo" WHERE somecond could be generated by this class.
Class	`Empty`	Undocumented
Class	`Join`	Used by sql.Query and sql.SQLCompiler to generate JOIN clauses into the FROM entry. For example, the SQL generated could be LEFT OUTER JOIN "sometable" T1 ON ("othertable"."sometable_id" = "sometable"...
Exception	`MultiJoin`	Used by join construction code to indicate the point at which a multi-valued join was attempted (if the caller wants to treat that exceptionally).