EXEC SQL

EXEC SQL is the marker that tells the DB2 precompiler "an SQL statement starts here". Every SQL statement inside a COBOL program - SELECT, INSERT, UPDATE, DELETE, OPEN, FETCH, CLOSE, COMMIT - is wrapped in EXEC SQL ... END-EXEC.

The EXEC SQL ... END-EXEC format

• Syntax: EXEC SQL sql-statement END-EXEC. The period after END-EXEC belongs to the COBOL sentence.
• EXEC SQL and END-EXEC are COBOL words as far as the precompiler is concerned; the SQL between them follows DB2 SQL syntax.
• The precompiler strips the SQL out, puts it in the DBRM, and leaves a CALL to the DB2 language interface in the modified source.
• There is also EXEC SQL INCLUDE ... END-EXEC, which pulls in a copybook (SQLCA or a DCLGEN member) at precompile time.

SQL statements you can code with EXEC SQL

• Data retrieval: SELECT ... INTO (single row), DECLARE CURSOR, OPEN, FETCH, CLOSE (multiple rows).
• Data change: INSERT, UPDATE, DELETE - including positioned UPDATE/DELETE with WHERE CURRENT OF cursor-name.
• Transaction control: COMMIT (save changes) and ROLLBACK (undo changes).
• Others: INCLUDE, WHENEVER (error handling directive), and dynamic SQL statements like PREPARE and EXECUTE.

INCLUDE variants

• EXEC SQL INCLUDE SQLCA END-EXEC brings in the SQL communication area, which holds SQLCODE after every statement.
• EXEC SQL INCLUDE member-name END-EXEC brings in a DCLGEN-generated copybook with table declaration and matching host variables.
• INCLUDE is processed at precompile time, like a COPY, not at COBOL compile time.

Example of the common EXEC SQL statements in one program:-