by Robert Sample » Thu Jul 07, 2011 5:36 pm
DB2, CICS, and COBOL are not modules.
DB2 is a relational database used to store and retrieve data.
CICS is an environment used to allow people to retrieve data and update it from a file or database.
COBOL is a programming language.
Depending upon the site, you may write COBOL programs to display screens of DB2 data in CICS and update the database using the changes keyed on the screen. Or you may write COBOL batch programs using DB2 databases without using CICS. Or you may write COBOL batch programs using sequential and VSAM files without having any database at all. Asking which is better is like asking which leg of a tripod is better-- a site may require all three, or only use two or one of them, and some sites may not use any of the three.
A really good student might be able to learn these concepts from the Internet, but you'd be far, far, far better off paying the money to get formal education.