Module 14:- Database Interface
- Use of SQL statements within source code of your program is known as Embedded SQL.
- COBOL allows you include Embedded SQL statements in your COBOL programs. Any language interfacing with DB2 is referred to as Host Language. In our case COBOL is Host Language.
- This feature allows COBOL programmer to directly perform standard SQL operation on database from COBOL program
- Prior to compilation, an embedded SQL program is processed by a special pre-processor or pre-compiler, which identifies the SQL statements, extracts and pass it to the DBMS for processing.
- While coding SQL statement in COBOL program, it must be enclosed between “EXEC SQL” and “END-EXEC”
EXEC SQL SELECT EMP_ID INTO :WS-ID FROM EMP END-EXEC.
- When such Embedded statements are executed, results are stored into COBOL variables referred to as Host Variables. This result storing functionality is achieved by specifying INTO clause in SELECT operation.
- In above example, “:WS-ID” is Host Variable