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. 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 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
• Usage
• Supported databases
• Contributing
• License
• Changelog
• To do

Install

You can get and install JayDeBeApi with pip

$ pip install JayDeBeApi

If you want to install JayDeBeApi in Jython make sure to have pip or EasyInstall available for it.

Or you can get a copy of the source by cloning from the JayDeBeApiArrow github project and install with

$ python setup.py install

or if you are using Jython use

$ jython setup.py install

It has been tested with Jython 2.7.2.

If you are using cPython ensure that you have installed JPype properly. It has been tested with JPype1 0.6.3 and 0.7.5 for Python 3 and with JPype1 0.6.3 and 0.7.0 for Python 2.7. Older JPype installations may cause problems.

Usage

Basically you just import the jaydebeapiarrow 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 second argument is a string with the JDBC connection URL. Third you can optionally supply a sequence consisting of user and password or alternatively a dictionary containing arguments that are internally passed as properties to the Java DriverManager.getConnection method. See the Javadoc of DriverManager class for details.

The next parameter to connect is optional as well and specifies the jar-Files of the driver if your classpath isn't set up sufficiently yet. The classpath set in CLASSPATH environment variable will be honored. See the documentation of your Java runtime environment.

Here is an example:

>>> import jaydebeapiarrow
>>> conn = jaydebeapiarrow.connect("org.hsqldb.jdbcDriver",
...                           "jdbc:hsqldb:mem:.",
...                           ["SA", ""],
...                           "/path/to/hsqldb.jar",)
>>> curs = conn.cursor()
>>> curs.execute('create table CUSTOMER'
...              '("CUST_ID" INTEGER not null,'
...              ' "NAME" VARCHAR(50) not null,'
...              ' primary key ("CUST_ID"))'
...             )
>>> curs.execute("insert into CUSTOMER values (?, ?)", (1, 'John'))
>>> curs.execute("select * from CUSTOMER")
>>> curs.fetchall()
[(1, u'John')]
>>> curs.close()
>>> conn.close()

If you're having trouble getting this work check if your JAVA_HOME environment variable is set correctly. For example I have to set it on my Ubuntu machine like this

$ JAVA_HOME=/usr/lib/jvm/java-8-openjdk python

An alternative way to establish connection using connection properties:

>>> conn = jaydebeapiarrow.connect("org.hsqldb.jdbcDriver",
...                           "jdbc:hsqldb:mem:.",
...                           {'user': "SA", 'password': "",
...                            'other_property': "foobar"},
...                           "/path/to/hsqldb.jar",)

Also using the with statement might be handy:

>>> with jaydebeapiarrow.connect("org.hsqldb.jdbcDriver",
...                         "jdbc:hsqldb:mem:.",
...                         ["SA", ""],
...                         "/path/to/hsqldb.jar",) as conn:
...     with conn.cursor() as curs:
...         curs.execute("select count(*) from CUSTOMER")
...         curs.fetchall()
[(1,)]

Supported databases

In theory every database with a suitable JDBC driver should work. It is confirmed to work with the following databases:

• SQLite
• Hypersonic SQL (HSQLDB)
• IBM DB2
• IBM DB2 for mainframes
• Oracle
• Teradata DB
• Netezza
• Mimer DB
• Microsoft SQL Server
• MySQL
• PostgreSQL
• many more...

Contributing

Please submit bugs and patches. 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

• Next version - unreleased
• 1.2.3 - 2020-06-12
  • Make pip install for Python 2 work by changing JPype1 requirement to older version
  • Make pip install for Jython work by removing JPype1 requirement for Jython
  • Removed cursor destructor to avoid issues with some JPype versions (please make sure you're always closing your cursors properly)
• 1.2.2 - 2020-06-04
  • Return (big) decimal types as long value if scale is zero (thanks to @ministat)
  • Fix DECIMAL and NUMERIC type conversion for Jython
• 1.2.1 - 2020-05-27
  • Increased thread safety. Should resolve some of the No suitable driver found errors (thanks to @thealmightygrant)
• 1.2.0 - 2020-05-22
  • Added compatibility to JPype1 0.7.2+ (thanks to @dpd)
  • Support with statement (thanks to @Szczepanov)
• 1.1.2 - 2019-09-02
  • Added compatibility to JPype1 0.7 (thanks to @Iverian, @Thrameos)
  • Dropped python 2.6 support
  • Fix build working with newer Maven versions
  • Accidently force-pushed to master branch. Sorry for that.
• 1.1.1 - 2017-03-21
  • Don't fail on dates before 1900 on Python < 3.
• 1.1.0 - 2017-03-19
  • Support BIT and TINYINT type mappings (thanks @Mokubyow for reporting the issue).
• 1.0.0 - 2017-01-10
  • Allow for db properties to be passed to the connect method. Probably incompatible to code based on previous versions. See documentation of the connect method. (Thanks @testlnord for you efforts and the patience.)
  • New major version due to possible api incompatibility.
• 0.2.0 - 2015-04-26
  • Python 3 support (requires JPype1 >= 0.6.0).
• 0.1.6 - 2015-04-10
  • Fix Jython handling of Java exceptions that don't subclass python Exception
  • Enrich exceptions with message from java SQLExceptions
  • Be more specific about DB API exceptions: Distinguish DatabaseError and InterfaceError.
  • Fix typo LONGNARCHAR vs LONGVARCHAR (thanks @datdo for reporting #4)
• 0.1.5 - 2015-03-02
  • Add version number to module.
  • Improve robustness of java to python type conversion.
  • Support Time type.
  • Add DB-API compliant exception handling.
  • Minor documentation improvements.
  • Some development related changes (Host project at github, use Travis CI, use JPype1 for tests).
• 0.1.4 - 2013-10-29
  • More convenient way to setup Java classpath. Important note check the changes to the connect method and adapt your code.
  • Honor CLASSPATH if used in JPype mode.
  • Set .rowcount properly.
  • Changed signature of .setoutputsize() to be DB-API compliant.
• 0.1.3 - 2011-01-27
  • 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 - 2011-01-25
  • easy_install JayDeBeApi should really work.
• 0.1.1 - 2010-12-12
  • Fixed bug #688290 "NULL values with converters error on fetch".
  • Fixed bug #684909 "Selecting ROWIDs errors out on fetch".
• 0.1 - 2010-08-10
  • Initial release.

To do

• Extract Java calls to separate Java methods to increase performance.
• Check if https://code.launchpad.net/dbapi-compliance can help making JayDeBeApi more DB-API compliant.
• Test it on different databases and provide a flexible db specific pluign mechanism.
• SQLAlchemy modules (separate project)