=================================================================
JayDeBeApi - bridge from JDBC database drivers to Python DB-API
=================================================================
The JayDeBeApi module allows you to connect from Python code to
databases using Java `JDBC
<http://java.sun.com/products/jdbc/overview.html>`_. It provides a
Python DB-API_ v2.0 to that database.
It works on ordinary Python (cPython) using the JPype_ Java
integration or on `Jython <http://www.jython.org/>`_ to make use of
the Java JDBC driver.
In contrast to zxJDBC from the Jython project JayDeBeApi let's you
access a database with Jython AND Python with only minor code
modifications. JayDeBeApi's future goal is to provide a unique and
fast interface to different types of JDBC-Drivers through a flexible
plug-in mechanism.
.. contents::
Install
=======
You can get and install JayDeBeApi with `easy_install
<http://peak.telecommunity.com/DevCenter/EasyInstall>`_ ::
$ easy_install JayDeBeApi
If you want to install JayDeBeApi in Jython make sure to have
EasyInstall available for it.
Or you can get a copy of the source branch using `bzr
<http://bazaar.canonical.com/>`_ by running ::
$ bzr branch lp:jaydebeapi
and install it with ::
$ python setup.py install
or if you are using Jython use ::
$ jython setup.py install
It has been tested with Jython 2.5.2.
If you are using cPython ensure that you have installed JPype_
properly. It has been tested with JPype 0.5.4.
Usage
=====
Basically you just import the ``jaydebeapi`` Python module and execute
the ``connect`` method. This gives you a DB-API_ conform connection to
the database.
The first argument to ``connect`` is the name of the Java driver
class. The rest of the arguments are internally passed to the Java
``DriverManager.getConnection`` method. See the Javadoc of
``DriverManager`` class for details.
Here is an example:
>>> import jaydebeapi
>>> conn = jaydebeapi.connect('org.hsqldb.jdbcDriver',
... 'jdbc:hsqldb:mem', 'SA', '')
>>> curs = conn.cursor()
>>> curs.execute('create table CUSTOMER'
... '("CUST_ID" INTEGER not null,'
... ' "NAME" VARCHAR not null,'
... ' primary key ("CUST_ID"))'
... )
>>> curs.execute("insert into CUSTOMER values (1, 'John')")
>>> curs.execute("select * from CUSTOMER")
>>> curs.fetchall()
[(1, u'John')]
You probably have to configure Jython or JPype to actually be able to
access the database driver's jar files. If I want to connect to a HSQL
in memory database on my Ubuntu machine I'm starting Python by running ::
$ JAVA_HOME=/usr/lib/jvm/java-6-openjdk python
Now I have to configure JPype
>>> import jpype
>>> jar = r'/path/to/my/driver/hsqldb.jar'
>>> args='-Djava.class.path=%s' % jar
>>> jvm_path = jpype.getDefaultJVMPath()
>>> jpype.startJVM(jvm_path, args)
or in Jython I have to
>>> jar = '/path/to/my/driver/hsqldb.jar'
>>> import sys
>>> sys.path.append(jar)
Supported databases
===================
In theory every database with a suitable JDBC driver should work. It
is known to work with the following databases:
+-----------------------------------------+------------------------------------------------+---------------+----------------------+
|Database |JDBC driver |Supported |Remarks |
+=========================================+================================================+===============+======================+
|`SQLite |`SqliteJDBC |Good |Can't interpret |
|<http://www.sqlite.org/>`_ |<http://www.zentus.com/sqlitejdbc/>`_ v056 | |selected BLOBs |
|3 | | |correctly. |
+-----------------------------------------+------------------------------------------------+---------------+----------------------+
| |`Sqlite Java Wrapper |Medium |Weird type handling. |
| |<http://www.ch-werner.de/javasqlite/>`_ | | |
| |javasqlite-20110106-win32 | | |
+-----------------------------------------+------------------------------------------------+---------------+----------------------+
|`Hypersonic SQL (HSQLDB) |Builtin |Very Good |No BLOB support |
|<http://hsqldb.org/>`_ 1.8.1.3 | | |by database. |
| | | | |
+-----------------------------------------+------------------------------------------------+---------------+----------------------+
|`Hypersonic SQL (HSQLDB) |Builtin |Medium |Weird decimal |
|<http://hsqldb.org/>`_ 2 | | |type |
| | | |conversions. No |
| | | |BLOB support. |
+-----------------------------------------+------------------------------------------------+---------------+----------------------+
|`IBM DB2 |JDBC type 4 drivers from IBM (``db2jcc.jar``) |Medium. |Not thoroughly tested |
|<http://www.ibm.com/software/data/db2/>`_| | |but seems to work |
|for z/OS | | |without problems. |
+-----------------------------------------+------------------------------------------------+---------------+----------------------+
|Oracle 11g |Oracle Thin Driver |Medium |Not thoroughly |
| | | |testst. No support for|
| | | |rading of timestamps |
| | | |yet. |
+-----------------------------------------+------------------------------------------------+---------------+----------------------+
|Other databases |Other JDBC drivers |Unkown |Please test yourself |
| | | |and report the |
| | | |results. |
| | | | |
+-----------------------------------------+------------------------------------------------+---------------+----------------------+
Contributing
============
Please submit `bugs and patches
<https://bugs.launchpad.net/jaydebeapi>`_. All contributors will be
acknowledged. Thanks!
License
=======
JayDeBeApi is released under the GNU Lesser General Public license
(LGPL). See the file ``COPYING`` and ``COPYING.LESSER`` in the
distribution for details.
Changelog
=========
- 0.1.4
- Set ``.rowcount`` properly.
- 0.1.3
- Fixed DB-API_ violation: Use ``curs.execute('foo ?', (bar, baz))``
instead of ``curs.execute('foo ?', bar, baz)``.
- Free resources after ``executemany`` call.
- Improved type handling. Initial support for BLOB columns.
- 0.1.2
- ``easy_install JayDeBeApi`` should really work.
- 0.1.1
- Fixed bug #688290 "NULL values with converters error on fetch".
- Fixed bug #684909 "Selecting ROWIDs errors out on fetch".
- 0.1
- Initial release.
To do
=====
- Extract Java calls to seperate Java methods to increase performance.
- Check if https://code.launchpad.net/dbapi-compliance can help making
JayDeBeApi more DB-API complient.
- Test it on different databases and provide a flexible db specific
pluign mechanism.
- SQLAlchemy modules (seperate project)
.. _DB-API: http://www.python.org/dev/peps/pep-0249/
.. _JPype: http://jpype.sourceforge.net/
962f7c3afa