Processing SQL statements for program preparation

The first step in preparing an SQL application to run is to process the SQL statements in the program. To process the statements, use the Db2 coprocessor or the Db2 precompiler. During this step, the SQL statements are replaced with calls to Db2 language interface modules, and a DBRM is created.

About this task

Because most compilers do not recognize SQL statements, you can prevent compiler errors by using either the Db2 coprocessor or the Db2 precompiler.

You can use the Db2 coprocessor for the host language. When you use the Db2 coprocessor, the compiler (rather than the Db2 precompiler) scans the program and returns the modified source code. The Db2 coprocessor also produces a DBRM.

Tip: The Db2 coprocessor is the recommended method for processing SQL statements in application programs. Compared to the Db2 precompiler, the Db2 coprocessor has fewer restrictions on SQL programs, and more fully supports the latest SQL and programming language enhancements. See Processing SQL statements by using the Db2 coprocessor.

The Db2 precompiler scans the program and returns modified source code, which you can then compile and link edit. The precompiler also produces a DBRM (database request module). You can bind this DBRM to a package using the BIND subcommand. When you complete these steps, you can run your Db2 application.

Db2 version in DSNHDECP module

When you process SQL statements in your program, if the Db2 version in DSNHDECP is the default system-provided version, Db2 issues a warning and processing continues. In this case, ensure that the information in DSNHDECP that Db2 uses accurately reflects your environment.

To process SQL statements in application programs, use one of the following methods:

• Invoke the Db2 coprocessor for the host language that you are using as you compile your program. You can use the Db2 coprocessor with C, C++, COBOL, and PL/I host compilers.
  To invoke the Db2 coprocessor, specify the SQL compiler option followed by its suboptions, which are those options that are defined for the Db2 precompiler. Some Db2 precompiler options are ignored. You can also invoke the Db2 coprocessor from UNIX System Services on z/OS® to generate a DBRM in either a partitioned data set or an HFS file.

  For more information, see Processing SQL statements by using the Db2 coprocessor.

• Use the Db2 precompiler before you compile your program. For more information, see Processing SQL statements by using the Db2 precompiler.
  For assembler or Fortran applications, use the Db2 precompiler to prepare the SQL statements.