Module 14:- Database Interface
DB2 Application Programming
COBOL-DB2 interface is governed by following rules:-
- Embedded SQL statement must be enclosed between “EXEC SQL” and “END-EXEC”
- Example:-
EXEC SQL SELECT EMP-ID INTO :WS-ID FROM EMP END-EXEC.
- Each EXEC SQL ... END-EXEC block must contain only one SQL statement.
- If the SQL command is not terminated by an END-EXEC operand, a COBOL compiler error will be generated.
- All SQL statements must be coded in Margin B.
- All SQL statements except INCLUDE and DECLARE must be coded in PROCEDURE DIVISION
- Structure (or Definition) of all the DB2 tables used withing program should have been included in WORKING-STORAGE SECTION using EXEC SQL INCLUDE statement
- All the Host Variables used in program must be declared in WORKING-STORAGE SECTION.
- Always suggested to include SQLCA to track SQL return code of executed SQL Statement. SQLCA is explained in following section.