How do you access IMS DB from COBOL programs?

IMS DB - Interview Questions

Accessing IMS DB (Information Management System Database) from COBOL programs involves utilizing DL/I (Data Language/I), which is the access method for IMS databases. DL/I provides a set of commands and functions that COBOL programs can use to interact with IMS databases efficiently.

Here's an overview of the steps involved in accessing IMS DB from COBOL programs :

* Include IMS-DL/I Statements
* Initialize DL/I Control Blocks
* Issue DL/I Calls
* Process Database Responses
* Commit or Rollback Transactions
* Close DL/I Resources

Here's an example of COBOL code accessing IMS DB using DL/I :

       IDENTIFICATION DIVISION.
       PROGRAM-ID. SAMPLE.
       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
       SELECT IMSDB-FILE ASSIGN TO IMSDB.
       DATA DIVISION.
       FILE SECTION.
       FD  IMSDB-FILE.
       01  IMSDB-RECORD.
           ...
       WORKING-STORAGE SECTION.
       01  PCB.
           ...
       01  PSB.
           ...
       PROCEDURE DIVISION.
           ...
           INITIALIZE PCB.
           INITIALIZE PSB.
           ...
           CALL 'DLI' USING PCB PSB.
           ...
           IF PCB-STATUS = '00'
               DISPLAY 'Database operation successful'
           ELSE
               DISPLAY 'Database operation failed: ' PCB-STATUS
           END-IF.
           ...
           STOP RUN.?

In this example, PCB and PSB are initialized before issuing DL/I calls. After performing database operations, the program checks the status code returned by DL/I to determine the outcome of the operation.