Multiple indexes on a table with various combinations

Question

Hi Experts,
This post is similar to my previous one on indexing. am just trying to understand proper indexing strategy.
Assuming that i have to use following queries frequently.
select Col1, Col2, Col3 from tab where col4='some value'
select Col1, Col2, Col3 from tab where col5='some value'
select Col1, Col2, Col3 from tab where col6='some value'
select Col1, Col2, Col3 from tab where col7='some value'
select Col1, Col2, Col3 from tab where col8='some value'
select Col1, Col2, Col3 from tab where col9='some value'
select Col1, Col2, Col3 from tab where col10='some value'
here, my doubt is, do we need to create "1 clustered + 6 NC covering" indexes (total 7) as we have 7 different columns in the where clause in 7 different select statements? Or, is there any better way of doing this?
Thanks,
Shiva

Answer 1

>am just trying to understand proper indexing strategy.
There is no such a thing. It is an art.
Generally you can use covering index for a business critical query. But that may slow down other queries because the covering index usually wide! You need to
check the execution plans for each query involved.
It is better to apply narrow fast indexes that way other queries will not slow.
Remember STATISTICS! It should be updated nightly:
http://www.sqlusa.com/articles/query-optimization/
The database engine uses the STATISTICS for the execution plan preparation not the index.
For best performance the indexes should be narrow (fast) and STATISTICS up-to-date.
Missing/fragmented/wide indexes & out-of-date STATISTICS are detrimental for performance.
Kalman Toth Database & OLAP Architect
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