DB2 for Linux on iSeries: Implementation Guide

80 DB2 UDB for Linux on iSeries: Implementation Guide

Figure 3-36 Type4 JDBC driver provided by DB2 UDB for Linux

The universal JDBC driver is the new JDBC driver which is provided with DB2

Version 8. This JDBC driver implements DRDA in it and can access all DB2 UDB

for LUW directly.

Since type 3 is the applet driver, a typical Java application is supposed to use

type 2 or type 4 driver. In this book, only type 2 and type 4 are discussed.

3.8.3 JDBC type 2 driver scenario

The JDBC type 2 driver relies on an OS-specific library (shared library) in the

database client-end to communicate with an RDBMS. In the case of Linux

application accessing DB2 UDB for iSeries, this library is packaged in the DB2

Client. In other words, you need a DB2 Client installed on the machine where the

JDBC type 2 application runs. This scenario is described in Figure 3-37.

DB2 Engine

DB2 UDB

for iSeries

OS/400

DRDA AS

DB2 Engine

DB2 UDB

for Linux

Linux

Java program

DB2 Type

4

JDBC driver

Client

Chapter 3. Connectivity with DB2 UDB for iSeries 81

Figure 3-37 DB2 type2 JDBC driver Scenario

How the JDBC type 2 driver works

The application will load the JDBC driver and the driver will use the shared library

to communicate with the DB2 server. Actually, DB2 UDB for Linux on iSeries

provides two different type 2 drivers:

򐂰 The CLI JDBC driver is provided in the file db2java.zip. The implementation

package name is COM.ibm.db2.jdbc.app.DB2Driver. This driver has been

used for the current J2EE certifications.

򐂰 The Universal JDBC driver, which is introduced as type 4 before, can also be

used as the type 2 driver. This driver is provided in the file db2jcc.jar. The

implementation package name is com.ibm.db2.jcc.DB2Driver. This driver is

new to DB2 UDB V8.1. In the initial implementation (V8.1), this driver was for

direct Java connectivity to DB2 servers using a type 4 driver architecture. In

Note: On the Linux side, you don’t need the DB2 Client, because it is

integrated in every edition of DB2 UDB for LUW available for iSeries, including

DB2 ESE.

DB2

Engine

AS05

Database

OS/400

Hostname: as05

DRDA AS

Schema : SAMPLEDB01

Alias : OS400

DB2 Engine

SAMPLE

Database

Linux on iSeries

Hostname: linux02

DB2 Connect

(DRDA AR)

Schema : DB2INST1

Alias : SAMPLE

JDBC type 2

driver

DB2 ESE

TestJDBC.java

82 DB2 UDB for Linux on iSeries: Implementation Guide

DB2 V8.1.2, you can use this driver in a type 2 architecture with the local DB2

Client. One of the key reasons for using the driver in a type 2 architecture is

for local application performance and for distributed transaction support. The

Universal JDBC type 2 driver supports distributed transactions using

com.ibm.db2.jcc.DB2XADataSource and connection pooling using

com.ibm.db2.jcc.DB2ConnectionPoolDataSource.

Both of these JDBC type 2 drivers are supported with WebSphere Application

Server. You can also use JDBC type 2 drivers to support Java-based client

applications.

Configuration

This section provides a step-by-step process of JDBC type 2 driver configuration.

1. Locate the JDBC drivers path. Usually, all JDBC drivers are in:

HOME_DIR/sqllib/java,

Here HOME_DIR is the instance owner’s home directory. In this scenario, the

instance name is db2inst1, thus the full path is:

/home/db2inst1/sqllib/java

2. Table 3-1 determines the appropriate JDBC driver you can use:

Table 3-1 Implementation Package JDBC drivers on DB2 UDB for Linux on iSeries

The CLI JDBC driver supports most existing applications, therefore it is

recommended to customers considering compatibilities important. The DB2

Universal JDBC driver is recommended for new users.

Note: Here are two other directories that may contain the JDBC drivers file:

򐂰 /opt/IBM/db2/V8.1/java

򐂰 /opt/IBM/db2/V8.1/java12

We recommend that you do

not to use them. They are the original

copies for the creation of DB2 instances.

򐂰 HOME_DIR/sqllib/java12

We recommend that you do

not to use it, because it is a back-level auxiliary

directory for JDBC 1.2 compatibility.

Driver Name Type Implementation Package

CLI JDBC driver 2 COM.ibm.db2.jdbc.app.DB2Driver

Universal JDBC driver 2 and 4 com.ibm.db2.jcc.DB2Driver