psycopg2/doc/extras.rst
2010-02-14 13:23:05 +00:00

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:mod:`psycopg2.extras` -- Miscellaneous goodies for Psycopg 2
=============================================================
.. sectionauthor:: Daniele Varrazzo <daniele.varrazzo@gmail.com>
.. module:: psycopg2.extras
.. testsetup::
import psycopg2.extras
create_test_table()
This module is a generic place used to hold little helper functions and
classes until a better place in the distribution is found.
.. index::
pair: Cursor; Dictionary
.. _dict-cursor:
Dictionary-like cursor
----------------------
The dict cursors allow to access to the retrieved records using an iterface
similar to the Python dictionaries instead of the tuples. You can use it
either passing :class:`DictConnection` as :obj:`!connection_factory` argument
to the :func:`~psycopg2.connect` function or passing :class:`DictCursor` as
the :class:`!cursor_factory` argument to the :meth:`~connection.cursor` method
of a regular :class:`connection`.
>>> dict_cur = conn.cursor(cursor_factory=psycopg2.extras.DictCursor)
>>> dict_cur.execute("INSERT INTO test (num, data) VALUES(%s, %s)",
... (100, "abc'def"))
>>> dict_cur.execute("SELECT * FROM test")
>>> rec = dict_cur.fetchone()
>>> rec['id']
1
>>> rec['num']
100
>>> rec['data']
"abc'def"
The records still support indexing as the original tuple:
>>> rec[2]
"abc'def"
.. autoclass:: DictCursor
.. autoclass:: DictConnection
.. autoclass:: DictRow
Real dictionary cursor
^^^^^^^^^^^^^^^^^^^^^^
.. autoclass:: RealDictCursor
.. autoclass:: RealDictConnection
.. autoclass:: RealDictRow
.. index::
pair: Cursor; Logging
Logging cursor
--------------
.. autoclass:: LoggingConnection
:members: initialize,filter
.. autoclass:: LoggingCursor
.. autoclass:: MinTimeLoggingConnection
:members: initialize,filter
.. autoclass:: MinTimeLoggingCursor
.. index::
pair: UUID; Data types
UUID data type
--------------
.. versionadded:: 2.0.9
.. versionchanged:: 2.0.13 added UUID array support.
.. doctest::
>>> psycopg2.extras.register_uuid()
<psycopg2._psycopg.type object at 0x...>
>>> # Python UUID can be used in SQL queries
>>> import uuid
>>> my_uuid = uuid.UUID('{12345678-1234-5678-1234-567812345678}')
>>> psycopg2.extensions.adapt(my_uuid).getquoted()
"'12345678-1234-5678-1234-567812345678'::uuid"
>>> # PostgreSQL UUID are transformed into Python UUID objects.
>>> cur.execute("SELECT 'a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11'::uuid")
>>> cur.fetchone()[0]
UUID('a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11')
.. autofunction:: register_uuid
.. autoclass:: UUID_adapter
.. index::
pair: INET; Data types
INET data type
--------------
>>> psycopg2.extras.register_inet()
<psycopg2._psycopg.type object at 0x...>
>>> cur.execute("SELECT '192.168.0.1'::inet")
>>> cur.fetchone()[0].addr
'192.168.0.1'
.. autofunction:: register_inet()
.. autoclass:: Inet
.. todo:: Adapter non registered: how to register it?
.. index::
single: Time zones; Fractional
Fractional time zones
---------------------
.. autofunction:: register_tstz_w_secs
.. versionadded:: 2.0.9