Are indexes nesessary to perform data retrieval

ratheesh_1983 · New User Joined: 11 Apr 2007 Posts: 19 Location: hyderabad

hi all,

Are indexes nesessary to perform data retrieval operations on a table? I have heard that db2 "need not" use the index while doing table operation

.
then , supposing that performance is not an issue , can we use tables without indices??

thanks in advance,
Ratheesh.

muthuvel · Posted: Thu Jul 12, 2007 3:21 pm

It is not a must that each and every table should have an index.
As you have said,index is to improve the perfromance and provide faster access to data.
Each index is based on the values of data in one or more columns of a table.Improve performance and Ensure uniqueness are the key factors of indexing.

dick scherrer · Posted: Thu Jul 12, 2007 10:04 pm

Hello,

Hopefully, it is realized that if there are no key definition(s) every time the table is read every row in the table will be read - the code may choose to skip unwanted rows, but every one must be read.