diff options
Diffstat (limited to 'lib/sqlalchemy/sql/schema.py')
| -rw-r--r-- | lib/sqlalchemy/sql/schema.py | 48 |
1 files changed, 28 insertions, 20 deletions
diff --git a/lib/sqlalchemy/sql/schema.py b/lib/sqlalchemy/sql/schema.py index b7d6743be..1cdc7b425 100644 --- a/lib/sqlalchemy/sql/schema.py +++ b/lib/sqlalchemy/sql/schema.py @@ -2227,26 +2227,34 @@ class Sequence(DefaultGenerator): reserved words take place. :param quote_schema: set the quoting preferences for the ``schema`` name. - :param metadata: optional :class:`.MetaData` object which will be - associated with this :class:`.Sequence`. A :class:`.Sequence` - that is associated with a :class:`.MetaData` gains access to the - ``bind`` of that :class:`.MetaData`, meaning the - :meth:`.Sequence.create` and :meth:`.Sequence.drop` methods will - make usage of that engine automatically. - - .. versionchanged:: 0.7 - Additionally, the appropriate CREATE SEQUENCE/ - DROP SEQUENCE DDL commands will be emitted corresponding to this - :class:`.Sequence` when :meth:`.MetaData.create_all` and - :meth:`.MetaData.drop_all` are invoked. - - Note that when a :class:`.Sequence` is applied to a :class:`.Column`, - the :class:`.Sequence` is automatically associated with the - :class:`.MetaData` object of that column's parent :class:`.Table`, - when that association is made. The :class:`.Sequence` will then - be subject to automatic CREATE SEQUENCE/DROP SEQUENCE corresponding - to when the :class:`.Table` object itself is created or dropped, - rather than that of the :class:`.MetaData` object overall. + + :param metadata: optional :class:`.MetaData` object which this + :class:`.Sequence` will be associated with. A :class:`.Sequence` + that is associated with a :class:`.MetaData` gains the following + capabilities: + + * The :class:`.Sequence` will inherit the :paramref:`.MetaData.schema` + parameter specified to the target :class:`.MetaData`, which + affects the production of CREATE / DROP DDL, if any. + + * The :meth:`.Sequence.create` and :meth:`.Sequence.drop` methods + automatically use the engine bound to the :class:`.MetaData` + object, if any. + + * The :meth:`.MetaData.create_all` and :meth:`.MetaData.drop_all` + methods will emit CREATE / DROP for this :class:`.Sequence`, + even if the :class:`.Sequence` is not associated with any + :class:`.Table` / :class:`.Column` that's a member of this + :class:`.MetaData`. + + The above behaviors can only occur if the :class:`.Sequence` is + explicitly associated with the :class:`.MetaData` via this parameter. + + .. seealso:: + + :ref:`sequence_metadata` - full discussion of the + :paramref:`.Sequence.metadata` parameter. + :param for_update: Indicates this :class:`.Sequence`, when associated with a :class:`.Column`, should be invoked for UPDATE statements on that column's table, rather than for INSERT statements, when |