DB2 COBOL Compile Process

A COBOL DB2 program becomes executable in five stages: precompile, COBOL compile, link-edit, bind, and run. Miss a stage or run them in the wrong order and the program will not work. The diagram below shows the full flow.

The five stages

• 1. Precompile (DSNHPC): extracts the SQL into a DBRM and replaces it with CALL statements, producing the modified COBOL source.
• 2. COBOL compile (IGYCRCTL): compiles the modified source into an object module. The compiler never sees SQL.
• 3. Link-edit (IEWL): links the object module with the DB2 language interface module (DSNELI/DSNULI) into a load module.
• 4. Bind: reads the DBRM, validates against the catalog, optimizes, and stores the access path in a plan or package.
• 5. Run: the load module executes; its CALL statements reach DB2, which runs the bound SQL from the plan.

Typical build JCL layout

• One job with four steps in order: PRE (DSNHPC), COB (IGYCRCTL), LKED (IEWL), BIND (IKJEFT01 with DSN).
• Temporary datasets (&&) pass the modified source and object module between steps.
• The RUN step (IKJEFT01 with DSN RUN PROGRAM(...) PLAN(...)) executes the finished load module.
• Check the return code of every step: 0 is clean, 4 is warnings, 8 or more means errors - do not continue past errors.

Why the order matters

• Compiling before precompiling fails: the COBOL compiler cannot parse EXEC SQL blocks.
• Binding before compiling works, but rebinding is still required after every recompile because the DBRM timestamp changes.
• Linking without the DB2 interface module gives unresolved references at link time.

Example of a full DB2 COBOL build JCL (precompile, compile, link):-