DB2 for Linux on iSeries: Implementation Guide

Chapter 3. Connectivity with DB2 UDB for iSeries 77

򐂰 Type 1 are drivers that implement the JDBC API as a mapping to another

data access API, such as Open Database Connectivity (ODBC). Drivers of

this type are generally dependent on a native library, which limits their

portability. The JDBC-ODBC Bridge driver is an example of a Type 1 driver.

򐂰 Type 2 are drivers that are written partly in the Java programming language

and partly in native code. The drivers use a native client library specific to the

data source to which they connect. Again, because of the native code, their

portability is limited.

򐂰 Type 3 are drivers that use a pure Java client and communicate with a

middleware server using a database-independent protocol. The middleware

server then communicates the client’s requests to the data source.

򐂰 Type 4 are drivers that are pure Java and implement the network protocol for

a specific data source. The client connects directly to the data source.

3.8.2 JDBC drivers provided by DB2 UDB for Linux

DB2 UDB for Linux provides Type 2, Type 3, and Type 4 JDBC drivers. DB2 UDB

for Linux Type 2 and Type 3 drivers use the DB2 CLI (Call Level Interface)

interface to communicate to DB2 UDB servers. The JDBC Type 2 and Type 3

drivers are provided in the db2java.zip file located in the sqllib/java directory.

DB2 Version 8 adds a new DB2 JDBC Universal Driver (Type 4), which uses the

Distributed Relational Database Architecture™ (DRDA) protocol for client/server

communications. This new driver is provided in the db2jcc.jar file in the

sqllib/java directory. In DB2 UDB 8.1.2, the DB2 JDBC Universal Driver also

can be used as a Type 2 driver.

Type 2 driver (Application driver)

Figure 3-34 illustrates the mechanism in which the type 2 JDBC driver works.

The client layer is added for explanation purposes, but the client facility can also

reside in Linux.

78 DB2 UDB for Linux on iSeries: Implementation Guide

Figure 3-34 Type 2 JDBC driver provided by DB2 UDB for Linux

The type 2 driver, which is called “DB2 JDBC application driver” enables Java

applications to make calls to DB2 through JDBC. The Java applications that use

this driver must run on a DB2 Client, through which JDBC requests flow to the

DB2. DB2 Client is the “native client library” needed for the type 2 driver in this

case. When you use the type 2 driver in the Linux, you do not need DB2 Client,

because the DB2 UDB for Linux server also has the client facility. If you want to

access DB2 UDB for iSeries by this driver, DB2 Connect Version 8

license/installation is required in the Linux partition.

Type 3 driver (Applet driver or net driver)

Figure 3-35 illustrates the mechanism in which the type 3 JDBC driver works.

The client layer is added for explanation purposes but the client facility can also

reside in Linux.

Note: In reality, you don’t need DB2 Client product on the client machine as far

as your client and Linux partition with DB2 UDB for LUW installed is the same

machine (that is, in the same Linux LPAR partition). This is because it is

integrated in every edition of DB2 for UDB for LUW available for iSeries.

DB2 Engine

DB2 UDB

for iSeries

OS/400

DRDA AS

DB2 Engine

DB2 UDB

for Linux

Linux

DB2 Connect

(DRDA AR)

Java program

DB2

Type2

JDBC driver

DB2 Client

(CLI interface)

Client