IMS is Information Management System. Ims is also one type of database management system used from very long back. IMS is heirarchial database management system . DB2 as compared is relational database management system. To know better difference about IMS & DB2 first you need to know different type of database management systems. There are a lot of differences between IMS & DB2. IMS is used in many projects because of it verstality & robustness and most widely because of a concept called checkpointing. See its not only IMS DB used in projects , a conjuction of DB(BATCH ) & DC(ONLINE) are used in many shops.
Pls have a lookin some manuals/books for more info. Also can just go thru the below IBM manuals
IMS/ESA V5 Appl Pgm: DB
IMS/ESA Version 4: Application Programming: Data Communication
Joined: 13 Jun 2007 Posts: 826 Location: Wilmington, DE
I've worked with both. I LOVE IMS!!!! It is eons faster than DB2 and data recovery is basically automatic. Before there was IMS, a lot of shops used VSAM which is almost like a sequential file - only with keys.
There was a lot of data redundacy. IMS was developed for the first moon project. It was not originally an IBM project. Long story short, IBM got into the picture and millions of people came online! YAY!
So if you think of it this way, IMS is the child of VSAM - DB2 is a close relative. I relate it like the root segment of an IMS heir database is the first normal of a relation DB2 database, etc, etc. I still like IMS much better.