Data sources

As defined in the Sun JDBC 2.0 Standard Extension specification, data sources allow you to manage a pool of connections to a database. Using connection pools provides you with the following advantages:

• It improves performance. Creating connections is expensive; a data source creates a connection as soon as it is instantiated.

• It simplifies resource allocation. Resources are only allocated from the data sources, and not at arbitrary places in the code.

• It simplifies connection calls. To get a connection in JDBC 1.0, you would need to call Class.forName() on the class name of the database driver, before making DriverManager calls.

Data sources work as follows:

1. When a client wants to use a connection, it looks up a data source by name from a JNDI server.

2. The data source then returns a connection to the client.

3. If the data source has no more connections, it may ask the database manager for more connections (as long as it has not exceeded the maximum number of connections).

4. When the client has finished with the connection, it closes the connection.

5. The data source then returns the connection to the available pool.

You can configure data sources for WebSphere® Application Server v6.x by using the Deployment page in the application deployment descriptor editor or using the administrative console.

 

Related tasks

Creating tables and data sources automatically to test CMP beans

...on WAS v6.1.x

Creating tables and data sources automatically to test CMP beans

...on WAS v6.0.x

 

Related reference

Using the table and data source creator with the DB2 v8.2 or v8.1 type 4 JDBC driver

Using the table and data source creator with the DB2 v8.2 or v8.1 type 4 JDBC driver

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