<< Network client driver examples | Statement caching example >>

Accessing the Network Server

<< Network client driver examples | Statement caching example >>

Derby Server and Administration Guide

//
Class.forName("org.apache.derby.jdbc.ClientDriver");
// Set user and password properties
Properties properties = new Properties();
properties.setProperty("user", "judy");
properties.setProperty("password", "no12see");
// Get a connection
Connection conn = DriverManager.getConnection(databaseURL, properties);

Accessing the Network Server by using a DataSource object

The Network Server supports the Derby Network Client driver

DataSource

classes

org.apache.derby.jdbc.ClientDataSource

and

org.apache.derby.jdbc.ClientConnectionPoolDataSource

on all supported

Java SE platforms.

If your client runs on the Java SE 6 platform, and if you want to use

DataSource

methods specific to the JDBC 4 API, use the

DataSource

classes named

org.apache.derby.jdbc.ClientDataSource40

and

org.apache.derby.jdbc.ClientConnectionPoolDataSource40

If your client is running on the Java SE 6 platform, all connection objects returned from
the

DataSource

will be JDBC 4 connection objects, whether or not you are using a

DataSource

whose name ends in "40".

Using statement caching

Derby supports JDBC statement caching, which can improve the performance of
applications that use

PreparedStatement

CallableStatement

objects.

Statement caching avoids the performance penalty incurred by going over the network
from the client to the server to prepare a statement that has already been prepared on
the same connection.

To use statement caching, you must use an

org.apache.derby.jdbc.ClientConnectionPoolDataSource

or an

org.apache.derby.jdbc.ClientConnectionPoolDataSource40

object. After

you instantiate this object, perform these steps:

1. Specify the desired size of your statement cache by calling the

setMaxStatements

method on the

DataSource

object, specifying an argument

greater than zero.

2. Call the

getPooledConnection

method on the

DataSource

object to obtain a

javax.sql.PooledConnection

object (a physical connection).

3. Call the

javax.sql.PooledConnection.getConnection

method to obtain a

java.sql.Connection

object (a logical connection).

After you obtain a connection, use either prepared statements or callable statements to
interact with the database. Close each statement to return it to the cache after you finish
using it. The statements you create are held in the cache on the client side and reused
when needed.

See

Statement caching example

for a code example.

Use of the JDBC statement cache makes each physical connection use more memory.
The amount depends on how many statements the connection is allowed to cache and
how many statements are actually cached.

If you enable JDBC statement caching, error handling changes slightly. Some errors that
previously appeared when the

prepareStatement

method was executed may now

appear during statement execution. For example, suppose you query a table using a
prepared statement that is then cached. If the table is deleted, the prepared statement
that queries the table is not invalidated. If the query is prepared again on the same