Mainframe, MVS and zOS Discussion

Hi,

What is the difference between IDMS and DB2? Are they just same - please tell me? I searched on it but got more confused.

IDMS is a database system from a third-party vendor called Computer Associates (CA). It and DB2 have organizational differences in defining data bases and using them in programs, but your question is so broad as to be meaningless.

IDMS and DB2 are two different animals - though they belong to same breed called "Data Base".

IDMS (Integrated Database Management System) is primarily a network database management system for mainframes and owned by CA, as Robert has also said. On the other hand, DB2 is a "relational" in its nature. So IDMS is referred as NDBMS (Network Data Base Management Systems) also while DB2 is referred as RDBMS (Relational Data Base Management Systems). Having said that, if we go by the very definitions of these two systems - RDBMS is a DBMS in which data is perceived to be stored in the form of tables and so the relationship among the data is also stored in the form of tables and it follows Codd's rule. NDBMS, on the other hand, is a set of records which is having owner and member relationship within the set.

There had been claims that DB2 was (compared to IDMS) very (and still is) I/O intensive and is nothing more than a means to sell IBM DASD, however, I, for one, cannot vouch for that.

Hope this helps.

Thanks Robert and Anuj.