Re: Enforcing uniqueness on [real estate/postal] addresses

>Is is possible to have two entries which have the same
>address_identifier_general, street and postcode, but different
>descriptions?

Unfortunately, yes.  The data comes from gov't systems to
regulate the development/alteration of arbitrary pieces of property and
those pieces do not always have a postal address.  E.g. a farmer may
one year apply to erect a wind turbine in "field north of Foo Cottage"
and the next year apply to demolish "barnhouse west of Foo Cottage".

Now, I know what you are thinking, there is a normalization opportunity and you
may well be right. However, the problem does exist in some of the other fields
too and I am already facing a fair amount of join complexity in my schema so I
am trying to figure out my options :)

>(What is an address_identifier_general, btw?)
Address identifier composed by numbers and/or characters. I'm using the
terminology from the EU's "INSPIRE Data Specification on Addresses" Guidelines.

I haven't yet had the opportunity to try out the above suggestions but I will
post again when I have.