Database backends

Backends are implemented using the great Jython’s zxJDBC package, which makes any database with a working JDBC driver accessible through the DB-API 2.0 specification. Thus, to use any backend from this project, you will also need the corresponding JDBC driver somewhere in your CLASSPATH. On Unix-based environments this can be done on the console by running:

$ export CLASSPATH="$CLASSPATH:/path/to/driver.jar"

Note that this is a ephemeral setting that will only have effect on the current shell session.

PostgreSQL

Developed and tested against PostgreSQL v9.3 with the JDBC driver 9.1-902.jdbc4. To use it set the following in your Django project settings:

DATABASES = {
  'default': {
    # ...
    'ENGINE': 'doj.db.backends.postgresql',
  }
}

Download the JDBC Driver from http://jdbc.postgresql.org/download.html and remember to put the JAR file on the CLASSPATH.

SQLite3

Developed and tested against SQLite3 v3.7.6 with the JDBC driver 3.7.2. To use it set the following in your Django project settings:

DATABASES = {
  'default': {
    # ...
    'ENGINE': 'doj.db.backends.sqlite',
  }
}

Download the JDBC Driver from https://bitbucket.org/xerial/sqlite-jdbc/downloads and remember to put the JAR file on the CLASSPATH.

MySQL

Developed and tested against SQLite3 v3.7.6 with the JDBC driver 3.7.2. To use it set the following in your Django project settings:

DATABASES = {
  'default': {
    # ...
    'ENGINE': 'doj.db.backends.mysql',
  }
}

Download the JDBC Driver from https://bitbucket.org/xerial/sqlite-jdbc/downloads and remember to put the JAR file on the CLASSPATH.

MSSQL

Developed and tested against MSSQL 2008 with the JDBC driver 1.3.0. To use it set the following in your Django project settings:

DATABASES = {
  'default': {
    # ...
    'ENGINE': 'doj.db.backends.mssql',
  }
}

Download the JDBC Driver from http://jtds.sourceforge.net/ and remember to put the JAR file on the CLASSPATH.

JNDI support

All the backends documented on the previous sections support JNDI lookups to leverage connection pools provided by Java application servers. To use JNDI, simply add the following line to the project’s settings.py:

DATABASES = {
  'default': {
    # ...
    'OPTIONS': {
      'JNDI_NAME': 'java:comp/env/jdbc/myDataSource',
    }
  }
}

And make sure that the datasource specified as the JNDI_NAME is defined on the application server in which you will deploy your application.

Note

When using JNDI and with the exception of ENGINE, all the other options will be ignored by django-jython. For ease of development you may want to add the JNDI_NAME option only to the staging and production servers. After all, on most cases you won’t really need database connection pooling when testing on your development machine.

Specifying additional JNDI options

Additionally, you can use the 'JNDI_CONTEXT_OPTIONS' entry of the OPTIONS dictionary to pass additional options to set up the underlying JNDI InitialContext. The options are themselves specified as another dictionary. For example:

DATABASES = {
  'default': {
    # ...
    'OPTIONS': {
      'JNDI_NAME': 'java:comp/env/jdbc/myDataSource',
      'JNDI_CONTEXT_OPTIONS': {
        'java.naming.factory.initial': 'com.sun.appserv.naming.S1ASCtxFactory',
        'com.sun.appserv.iiop.endpoints': 'localhost:3700',
      }
    }
  }
}

Note that usually you don’t need to pass additional options for JNDI to work if the application has been deployed on a JavaEE container (such as Tomcat, Glassfish, JBoss, Websphere, Weblogic, etc). We provide this setting for flexibility and completeness. But on most cases the configuration will look like the one-liner shown on the first JNDI settings example.

JNDI and Tomcat

To use django-jython JNDI support on top of Apache Tomcat, add the JNDI configuration line to your settings.py:

DATABASES = {
  'default': {
    # ...
    'OPTIONS': {
      'JNDI_NAME': 'java:comp/env/jdbc/myDataSource'
    }
  }
}

Do not remove the other database settings, as they will be used by django-jython to help you create your JNDI configuration.

Deploy your application as normal. It won’t work (raising a JNDI exception telling you that the jdbc name is not bound in this Context), but we will fix that now. Use the jndiconfig management command to get a sample context XML file to set up your data source:

$ jython manage.py jndiconfig

You will see an output similar to this:

<!-- This is the JNDI datasource configuration for mysite -->
<Context>
  <!-- Some documentation... -->
  <Resource name="jdbc/myDataSource"
            auth="Container"
            type="javax.sql.DataSource"
            username="root"
            password="root"
            driverClassName="com.mysql.jdbc.Driver"
            url="jdbc:mysql://localhost:3306/mydatabase?zeroDateTimeBehavior=convertToNull"
            maxActive="8"
            maxIdle="4"
            maxWait="10000"/>
</Context>

Usage hint:
  For a basic configuration of JNDI on your Tomcat server, create a file named mysite.xml on
  '/path/to/apache-tomcat-6.x.x/conf/Catalina/localhost/' with the content printed above.

Follow the instructions, restart Tomcat and it will be working as expected.