Hi,

I'm looking for some advice concerning queries on a table. It's a
table which contains: zipcode, state, streetname, streetnumber range
and a value.

I need to look this value up for each different street (and depending
on the streetnumber). This can be very intensive (ie a lot of
lookups), so the search should be quick. So I could put an index on
zipcode, state and streetname and search the value this way.

If the combination doesn't exist, I let the user add the combination,
together with a value.

Now I heard of another approach in which you have another column,
which is eg a hashcode of the 3 columns. They tell me that this
approach will perform much better, which might be possible.

Can anybody give some of their experience on this and perhaps point me
to a place where I can find more information on creating this hashed key?

Thanks in advance