diff options
Diffstat (limited to 'lib/sqlalchemy')
| -rw-r--r-- | lib/sqlalchemy/dialects/postgresql/base.py | 52 | ||||
| -rw-r--r-- | lib/sqlalchemy/schema.py | 8 |
2 files changed, 50 insertions, 10 deletions
diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py index 3193cde9e..4c66ee91a 100644 --- a/lib/sqlalchemy/dialects/postgresql/base.py +++ b/lib/sqlalchemy/dialects/postgresql/base.py @@ -75,14 +75,43 @@ use the :meth:`._UpdateBase.returning` method on a per-statement basis:: where(table.c.name=='foo') print result.fetchall() -Indexes -------- -PostgreSQL supports partial indexes. To create them pass a postgresql_where -option to the Index constructor:: +.. _postgresql_indexes: + +Postgresql-Specific Index Options +--------------------------------- + +Several extensions to the :class:`.Index` construct are available, specific +to the PostgreSQL dialect. + +Partial Indexes +^^^^^^^^^^^^^^^^ + +Partial indexes add criterion to the index definition so that the index is +applied to a subset of rows. These can be specified on :class:`.Index` +using the ``postgresql_where`` keyword argument:: Index('my_index', my_table.c.id, postgresql_where=tbl.c.value > 10) +Operator Classes +^^^^^^^^^^^^^^^^^ + +PostgreSQL allows the specification of an *operator class* for each column of +an index (see http://www.postgresql.org/docs/8.3/interactive/indexes-opclass.html). +The :class:`.Index` construct allows these to be specified via the ``postgresql_ops`` +keyword argument (new as of SQLAlchemy 0.7.2):: + + Index('my_index', my_table.c.id, my_table.c.data, + postgresql_ops={ + 'data': 'text_pattern_ops', + 'id': 'int4_ops' + }) + +Note that the keys in the ``postgresql_ops`` dictionary are the "key" name of +the :class:`.Column`, i.e. the name used to access it from the ``.c`` collection +of :class:`.Table`, which can be configured to be different than the actual +name of the column as expressed in the database. + """ import re @@ -570,12 +599,17 @@ class PGDDLCompiler(compiler.DDLCompiler): text = "CREATE " if index.unique: text += "UNIQUE " + ops = index.kwargs.get('postgresql_ops', {}) text += "INDEX %s ON %s (%s)" \ - % (preparer.quote( - self._index_identifier(index.name), index.quote), - preparer.format_table(index.table), - ', '.join([preparer.format_column(c) - for c in index.columns])) + % ( + preparer.quote( + self._index_identifier(index.name), index.quote), + preparer.format_table(index.table), + ', '.join([ + preparer.format_column(c) + + (c.key in ops and (' ' + ops[c.key]) or '') + for c in index.columns]) + ) if "postgres_where" in index.kwargs: whereclause = index.kwargs['postgres_where'] diff --git a/lib/sqlalchemy/schema.py b/lib/sqlalchemy/schema.py index 7323a5657..1763dc484 100644 --- a/lib/sqlalchemy/schema.py +++ b/lib/sqlalchemy/schema.py @@ -2079,7 +2079,13 @@ class Index(ColumnCollectionMixin, SchemaItem): Defines a composite (one or more column) INDEX. For a no-frills, single column index, adding ``index=True`` to the ``Column`` definition is - a shorthand equivalent for an unnamed, single column Index. + a shorthand equivalent for an unnamed, single column :class:`.Index`. + + See also: + + :ref:`schema_indexes` - General information on :class:`.Index`. + + :ref:`postgresql_indexes` - PostgreSQL-specific options available for the :class:`.Index` construct. """ __visit_name__ = 'index' |