Tuesday, August 5, 2014

DB2 Plan +Package+ and Collection ID ? Frequently Asked questions in interview

Having Covered the Basic steps in a cobol-db2 compilation process, lets have a bit of more clarification & brain storming to check our understanding :)

Q 1: Syntax Checking of the SQL statements are done in Precompilation time or Bind time?

Both. Let me explain it in details a bit. We all are aware of DCLGENS and we use INCLUDE statements in our cobol module to include the DCLGENS. Precompilation process only uses DCLGEN as the reference for table description (provided we use DCLGEN).It does not go and check the DB2 catalog for the table structure. If no DCLGEN is used, no synatx checking is done in precompilation time.
But,  During BIND time, the check is more rigorous and thorough because the DB2 catalog is accessed to check the table structure along with other information like access permission and others

Q2: Can 1 package have more than 1 DBRM ?
From 1 program, we get one DBRM and then we bind the DBRM into a package; in the sense, 1 package is the DB2-optimized version of the that single  DBRM. Each Package is nothing but a single bound DBRM. There is direct one to one relationship with application program and package.

Q3: Are packages executable?
No. In DB2, only plan is the executable module.

Will keep on adding as and when i come across!!..  suggestions most welcome!

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