>what is migration in mainframes using db2?
Suppose you are running Oracle or SQL server as your database system platform and your company wants to change the DB system .. hence, migrate to DB2 (using DB2 system utilities to help you migrate). We have used this term 'migrate' in the past to mean to move your appl/db to another new system/platform.
>what is encapsulation modules?
I am not much on theory, but looking into Computer Science fundamentals, this link might help you with your query: