Application design and development considerations for CICS DB2

During the design process

During the application design process, decisions you take can affect applications currently under development and planned future applications. Key design considerations include:
  • The relationship between CICS® applications and DB2® plans and packages. To gain the greatest benefits for the performance and administration of your system, the relationship between DB2 plans, transactions, and application programs must be defined when you are designing applications.
  • The locking strategy. Locking is affected by options you choose when creating tables in DB2 , by the design of your application programs, and by options you choose when binding plans, so you need to take it into account throughout the development process.
  • Consider the security aspects of both the CICS DB2 test system and the CICS DB2 production system.
  • Use of commands and programming techniques. These can improve the performance of your application and avoid potential problems. The use of qualified and unqualified SQL can also influence other aspects of the CICS DB2 environment. To run Java™ applications in the JVM server environment and gain the performance benefits of the open transaction environment (OTE), application programs must be threadsafe. For more information, see SQL, threadsafe and other programming considerations for CICS DB2 applications.
  • Java programs in the CICS DB2 environment. For information about the support and programming considerations, see Using JDBC and SQLJ to access DB2 data from Java programs .
  • Additional steps to take when application development is complete and the application is put into production.
  • Connections defined for improved performance. Define your CICS DB2 connections to enhance application performance. For example, using protected entry threads for the application programs to access DB2 improves performance for heavily-used applications.

Factors affected by design

The design that you implement can influence:
  • Performance
  • Concurrency
  • Operation
  • Security
  • Accounting
  • The development environment

Factors that affect application performance

A well-designed CICS DB2 application should work properly when initially deployed into a production environment. However, some factors can affect the performance of well-designed applications:

  • Increased transaction rate
  • Continued development of existing applications
  • More people involved in developing CICS DB2 applications
  • Existing tables used in new applications
  • Integration of applications

Because of these factors, it is important to develop a consistent set of standards on the use of DB2 in the CICS environment.

Applications with data stored in VSAM and DL/1

For applications that have data stored in VSAM or DL/I, differences exist in the way in which some processes work, when compared with CICS DB2 applications. Differences to consider are:
  • Locking mechanism
  • Security
  • Recovery and restart
  • BIND process
  • Operational procedures
  • Performance
  • Programming techniques

One of the main differences between batch program and online program design is that online systems should be designed for a high degree of concurrency. At the same time, no compromise should be made to data integrity. In addition, most online systems have design criteria related to performance.

Additional information

See the following additional sources of information on application design: