IBM z/OS Application Connectivity to DB2 for z/OS and OS/390
Published 20 January 2004, updated 22 July 2008
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Authors: Bart Steegmans
This Tip describes the no-charge feature that was initially made available for DB2 for z/OS V7after the publication of the related IBM Redbooks publication "DB2 for z/OS and OS/390: Ready for Java."
IBM z/OS Application Connectivity to DB2 for z/OS
z/OS Application Connectivity to DB2 for z/OS is a no-charge, optional feature initially made available with DB2 Universal Database Server for z/OS and OS/390, Version 7.
This feature consists of a component known as the DB2 Universal Database Driver for z/OS, Java Edition. This is a pure Java, Type 4 JDBC driver designed to deliver high performance and scalable remote connectivity for Java-based enterprise applications on z/OS to a remote DB2 for z/OS database server. The driver:
- Supports JDBC 2.0 and 3.0 specification and JDK V1.4 to deliver the maximum flexibility and performance required for enterprise applications
- Delivers robust connectivity to the latest DB2 for z/OS and WebSphere Application Server for z/OS
- Provides support for distributed transaction support (two-phase commit support)
- Enables custom Java applications that do not require an application server to run in a remote partition and connect to DB2 for z/OS
Many customers also have security guidelines to separate their Web server and database server. Therefore, both servers are not allowed to run on the same machine and must be separated by a firewall (see the top part of the figure).
In this case a WebSphere Application Server runs your Java applications and talks to a Type 2 JDBC driver. The JDBC driver talks through RRS to a DB2 system (DB2A) that is local to the machine running the WebSphere Application Server. This local DB2 then routes all requests to a remote database server (DB2B) using DRDA. In this configuration, DB2A does not have any databases that are accessed by the applications running on the WebSphere Application Server. All SQL requests are routed through the local DB2A, but are accessing data on the remote DB2B through DRDA.
In this configuration, we need the DRDA Application Requester functionality of DB2A to access the data residing on DB2B. This is because the (non-Universal) JDBC driver for z/OS and OS/390 is a Type 2 driver and cannot directly access a remote DB2 system (DB2B).
With IBM z/OS Application Connectivity to DB2 for z/OS (bottom part of the figure above), you no longer need a local DB2 (DB2A) on the same machine as your a WebSphere Application Server. This no-charge feature, new with DB2 for z/OS and OS/390 V7, provides a Type 4 JDBC driver that supports two-phase commit. (This driver is sometimes [unofficially] called the Type 4 XA driver.) Your Java applications running inside the a WebSphere Application Server talk to the (Universal) Type 4 JDBC driver that supports two-phase commit, and the driver talks directly to the remote database server (DB2B) through DRDA. The Universal Type 4 driver implements DRDA Application Requester functionality. You no longer need to buy a DB2 license for DB2A when using the DB2 Universal Database Driver for z/OS, Java Edition. It is sufficient to have a DB2 license for DB2B.
The z/OS Application Connectivity to DB2 for z/OS feature provides connectivity from a z/OS remote partition or system only. For access from any other operating system or platform, including z/Linux, to DB2 for z/OS, you must obtain a separate license of the edition of DB2 Connect that is appropriate for your environment.
This feature can only be ordered for DB2 for z/OS.
- If you have DB2 UDB Server for OS/390 Version 6 in your enterprise, you can use it to access data there (DB2B can be a V6 DB2 system), but certain technical limitations apply, such as, for example, XA two-phase commit functionality is not supported.
- DB2 UDB for OS/390 and z/OS V7 servers also do not have built-in support for distributed transactions that implement the XA specification. The DB2 Universal JDBC Driver emulates that support, but support distributed transactions (two-phase commit).
- DB2 UDB for z/OS Version 8 has native XA two-phase commit support in DRDA.
This no-charge feature has been available since December 19, 2003 with DB2 for z/OS Version 7.
For updated information on functions and products related to z/OS Application Connectivity to DB2 for z/OS feature for current versions of DB2 for z/OS, see the applicable announcement letter and program directory.
For the United States:
- IBM DB2 for z/OS Value Unit Edition, Software Announcement 208-041, dated February 26, 2008 (program directory GI10-8781)
- IBM DB2 V9.1 for z/OS, Software Announcement 207-041, dated March 6, 2007 (program directory GI10-8739)
- IBM DB2 UDB for z/OS V8, Software Announcement 204-029, dated March 2, 2004 (program directory GI10-8581)
This material has not been submitted to any formal IBM test and is published AS IS. It has not been the subject of rigorous review. IBM assumes no responsibility for its accuracy or completeness. The use of this information or the implementation of any of these techniques is a client responsibility and depends upon the client's ability to evaluate and integrate them into the client's operational environment.
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