diff options
Diffstat (limited to 'lib/sqlalchemy')
| -rw-r--r-- | lib/sqlalchemy/dialects/postgresql/base.py | 4 | ||||
| -rw-r--r-- | lib/sqlalchemy/orm/query.py | 12 | ||||
| -rw-r--r-- | lib/sqlalchemy/sql/expression.py | 17 |
3 files changed, 26 insertions, 7 deletions
diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py index e87c0426e..c31c23885 100644 --- a/lib/sqlalchemy/dialects/postgresql/base.py +++ b/lib/sqlalchemy/dialects/postgresql/base.py @@ -675,6 +675,10 @@ class PGCompiler(compiler.SQLCompiler): def for_update_clause(self, select): if select.for_update == 'nowait': return " FOR UPDATE NOWAIT" + elif select.for_update == 'read': + return " FOR SHARE" + elif select.for_update == 'read_nowait': + return " FOR SHARE NOWAIT" else: return super(PGCompiler, self).for_update_clause(select) diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py index 56d377f18..66d7f6eb4 100644 --- a/lib/sqlalchemy/orm/query.py +++ b/lib/sqlalchemy/orm/query.py @@ -1105,10 +1105,17 @@ class Query(object): ``FOR UPDATE`` (standard SQL, supported by most dialects) ``'update_nowait'`` - passes ``for_update='nowait'``, which - translates to ``FOR UPDATE NOWAIT`` (supported by Oracle) + translates to ``FOR UPDATE NOWAIT`` (supported by Oracle, + PostgreSQL) ``'read'`` - passes ``for_update='read'``, which translates to - ``LOCK IN SHARE MODE`` (supported by MySQL). + ``LOCK IN SHARE MODE`` (for MySQL), and ``FOR SHARE`` (for + PostgreSQL) + + ``'read_nowait'`` - passes ``for_update='read_nowait'``, which + translates to ``FOR SHARE NOWAIT`` (supported by PostgreSQL). + + New in 0.7.7: ``FOR SHARE`` and ``FOR SHARE NOWAIT`` (PostgreSQL) """ self._lockmode = mode @@ -2837,6 +2844,7 @@ class Query(object): if self._lockmode: try: for_update = {'read': 'read', + 'read_nowait': 'read_nowait', 'update': True, 'update_nowait': 'nowait', None: False}[self._lockmode] diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py index 6e16d01f8..f37faa801 100644 --- a/lib/sqlalchemy/sql/expression.py +++ b/lib/sqlalchemy/sql/expression.py @@ -244,11 +244,18 @@ def select(columns=None, whereclause=None, from_obj=[], **kwargs): :param for_update=False: when ``True``, applies ``FOR UPDATE`` to the end of the - resulting statement. Certain database dialects also support - alternate values for this parameter, for example mysql - supports "read" which translates to ``LOCK IN SHARE MODE``, - and oracle supports "nowait" which translates to ``FOR UPDATE - NOWAIT``. + resulting statement. + + Certain database dialects also support + alternate values for this parameter: + + * With the MySQL dialect, the value ``"read"`` translates to + ``LOCK IN SHARE MODE``. + * With the Oracle and Postgresql dialects, the value ``"nowait"`` + translates to ``FOR UPDATE NOWAIT``. + * With the Postgresql dialect, the values "read" and ``"read_nowait"`` + translate to ``FOR SHARE`` and ``FOR SHARE NOWAIT``, respectively + (new in 0.7.7). :param group_by: a list of :class:`.ClauseElement` objects which will comprise the |