Individual indexes vs multiple field indexes?

Personally I would recommend this approach Try the method with the single index that covers everything, if I recall correctly it will still perform well if you only query on the first of the included columns. Once you have the index in place, run the Index Advisor Then try the other route and repeat It really depends on your data I typically have been able to get by with 1 covering index, starting with the most frequently used key first.

Personally I would recommend this approach. Try the method with the single index that covers everything, if I recall correctly it will still perform well if you only query on the first of the included columns. Once you have the index in place, run the Index Advisor.

Then try the other route and repeat. It really depends on your data. I typically have been able to get by with 1 covering index, starting with the most frequently used key first.

That's exactly what I would do. – DL Redden Oct 16 '08 at 18:28.

It depends on how often the table is updated, and how complex the indexes are. If you go nuts creating indexes, then every time a record is inserted/updated/deleted, every index will have to be modified to reflect that information. If you only put three indexes on, and they are relatively simple, then you shouldn't have a problem.

I could be wrong, but I believe if you add: email, key1, key2, key3 as an index, that most databases will use it if your query is using "email", "email/key1", "email/key1/key2", etc... without requiring you to specify Null values for the missing fields.

As others have said, most databases will use the index "a, b, c" when searching for just a, a and be or a, be and c. And they will often only use one index per table. So adding "email, key1, key2, key3" will probably be the best.

That said, use EXPLAIN to find out what's really going on. Check to make sure what indexes, if any, your queries are using. Every database has its quirks.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.