Before I write about Index i just want to make clear the difference between Primary key and index:
Primary key: It is not allowed duplicates
Index: It speeds up performance of access.
There are 7 indexes in DB2.
- Clustering index: It helps the way data physically stored in database
- Uniq index: This will be given normally with primary key column. The value is unique.
- Partitioned index: Index is located in partitioned datasets
- NPS: Non-partitioned secondary index
- DPSI: Data partitioned secondary index
- Single column index: Index on only one column
- Multi column index: Index on multi columns