find duplicate addresses in database, stop users entering them early?

Question

How do I find duplicate addresses in a database, or better stop people already when filling in the form ? I guess the earlier the better?

Is there any good way of abstra

Answer 1

One thing you might want to look at are Soundex searches, which are quite useful for misspellings and contractions.

This however is not an in-database validation so it may or may not be what you're looking for.