Sun Microsystems 820433510 manual Jdbc Connection Pools

JDBC Connection Pools

When creating a JDBC resource, you must identify:

1.The JNDI Name. By convention, the name begins with the jdbc/ string. For example: jdbc/payrolldb. Don’t forget the forward slash.

2.Select a connection pool to be associated with the new JDBC resource.

3.Specify the settings for the resource.

4.Identify the targets (clusters and standalone server instance) on which the resource is available.

JDBC Connection Pools

To create a JDBC resource, specify the connection pool with which it is associated. Multiple JDBC resources can specify a single connection pool.

A JDBC connection pool is a group of reusable connections for a particular database. Because creating each new physical connection is time consuming, the server maintains a pool of available connections to increase performance. When an application requests a connection, it obtains one from the pool. When an application closes a connection, the connection is returned to the pool.

The properties of connection pools can vary with different database vendors. Some common properties are the database’s name (URL), user name, and password.

See Also:

■“JDBC Resources” on page 43

■“How JDBC Resources and Connection Pools Work Together” on page 44

■“Editing a JDBC Connection Pool” on page 48

How JDBC Resources and Connection Pools Work Together

To store, organize, and retrieve data, most applications use relational databases. Java EE applications access relational databases through the JDBC API. Before an application can access a database, it must get a connection.

At runtime, here’s what happens when an application connects to a database:

1.The application gets the JDBC resource (data source) associated with the database by making a call through the JNDI API.

Given the resource’s JNDI name, the naming and directory service locates the JDBC resource. Each JDBC resource specifies a connection pool.

2.Via the JDBC resource, the application gets a database connection.

44 Sun GlassFish Enterprise Server 2.1 Administration Guide • December 2008