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Wednesday, April 28, 2010

DB2-IMS - Few Difference


Cobol-DB2 Cobol -IMS



1 Need to Prcompile
to generate 1. DBRM (Sql Staments only)
2. Cobol Object code
No Precompilation Required
2 Bind the DBRM to Generate Plan. Plan consists of
Executable SQL Quries
No Bind Process is Required.
Here we Write PSBs to fetch respective Record.
3 Compile Cobol Code Compile Cobol-Ims program
4 Execute Cobol - DB2 Program using IKJEFT01, where in we
Specify Program Name and Plan Name to be Executed
Execute Cobol-IMS program using DFSRRC00. Pass Program Name , PSB, Name, Plan name Thru Parm Parameter




Why We need BIND In DB2 not in IMS




Say below query is written in Cobol-Db2 Program Equivalent IMS Call



1 Select A, B, C First Define PCB to Fetch the field A, B, C

Where A=10 Using DLI Call fetch the field A, B, C specified in above PCB


CALL CBLTDLI USING GU , PCB-NAME , SSA-Field
(Populate Key value 10 to SSA)
2 Above Query turned to executable query by binding Plan compile PSB (can hold n no of PCBS)
3 use this plan to execute the Program (while executing Cobol- Db2 Program, when a DB2 statement is encountered, system refers to plan to execute respective query) Using This PSBLIB to execute the CBLTDLI call. (while executing Cobol-IMS Program, when a DLI /IMS statement is encountered, system points to respective segment to be fetched using respective PCB)