topic Re: Index usage in Application Development and Automation Discussions

Index usage

former_member194704 — Tue, 14 Oct 2008 06:13:17 GMT

Table ztest has a secondary index on the following fields:

tnum, tcode.

Select * from ztest where tnum ne '123' and tcode = '456'.

Why is the index not used in the above case?

a) Indexes are not allowed on Z tables

b) Variables must be used, NOT literals

c) Select individual fields, not select *

d) Client is not in the where clause

e) NE invalidates the use of an index

Can you help me? Is it option a)?

Thanks & Regards,

Lohit

Re: Index usage

Former Member — Tue, 14 Oct 2008 06:15:52 GMT

Hi,

Answer is option c & e.

Regards,

Amit

Re: Index usage

madan_ullasa — Tue, 14 Oct 2008 06:17:15 GMT

Hi,

There is nothing specific you need to do to use the indexed keys... Its more of an internal process for faster access of the values...Just see to that you use the keys in where condition in the same sequence as found in your table...

regds,

Madan...

Re: Index usage

Former Member — Tue, 14 Oct 2008 06:18:57 GMT

Hi,

You have to use all the fields used for indexing in where clause of the select query.

Regards,

Renjith Michael.