From 21f47124ab433cc74fa0a72efcc8a6c1e9c37db5 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Thu, 1 Jan 2015 13:47:08 -0500 Subject: - restate sort_tables in terms of a more fine grained sort_tables_and_constraints function. - The DDL generation system of :meth:`.MetaData.create_all` and :meth:`.Metadata.drop_all` has been enhanced to in most cases automatically handle the case of mutually dependent foreign key constraints; the need for the :paramref:`.ForeignKeyConstraint.use_alter` flag is greatly reduced. The system also works for constraints which aren't given a name up front; only in the case of DROP is a name required for at least one of the constraints involved in the cycle. fixes #3282 --- lib/sqlalchemy/dialects/sqlite/base.py | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'lib/sqlalchemy/dialects/sqlite') diff --git a/lib/sqlalchemy/dialects/sqlite/base.py b/lib/sqlalchemy/dialects/sqlite/base.py index e0b2875e8..3d7b0788b 100644 --- a/lib/sqlalchemy/dialects/sqlite/base.py +++ b/lib/sqlalchemy/dialects/sqlite/base.py @@ -201,6 +201,15 @@ new connections through the usage of events:: cursor.execute("PRAGMA foreign_keys=ON") cursor.close() +.. warning:: + + When SQLite foreign keys are enabled, it is **not possible** + to emit CREATE or DROP statements for tables that contain + mutually-dependent foreign key constraints; + to emit the DDL for these tables requires that ALTER TABLE be used to + create or drop these constraints separately, for which SQLite has + no support. + .. seealso:: `SQLite Foreign Key Support `_ @@ -208,6 +217,9 @@ new connections through the usage of events:: :ref:`event_toplevel` - SQLAlchemy event API. + :ref:`use_alter` - more information on SQLAlchemy's facilities for handling + mutually-dependent foreign key constraints. + .. _sqlite_type_reflection: Type Reflection -- cgit v1.2.1