Indexes

[Joakim Schramm]

Hi,

This may be a kind of "stupid" question, but I am not that in depth familiar
with all agles of databases.

I simply wonder "when" is it really benefital or even necessary to index a
field? Is it soley in regards of searches? I assume a field can be searched
if not indexed as well, but lets say if it just is question of random or not
so frequent searches, mostly looking for and returning a single records, how
big impact are we talking of here in performance? I assume count of records
also makes a difference here? Lets say it just 10000 or even 1000 records to
search does an index really make a notible difference?

Any good guidelines?

Thanks,

Joakim