Here are some helpful queries you can run through your SQL interface.  Records that are not inter-connected in the Goldmine database (known as Orphan Records) can cause some major issues, especially if you are planning on upgrading.

--this one gives you a record count:

select count(accountno) from contact1

-- this one should come back as zero:

select count(accountno) from contact1
where accountno not in (select accountno from contact2)

--this one should have less than 5:

select count(accountno) from contact2
where accountno not in (select accountno from contact1)

--lastly, check your history:

select count(accountno) from conthist
where accountno not in (select accountno from contact1)

If any of the last 3 queries results in any value above 20, you should contact your Goldmine Consultant  and discuss methods of cleaning your database.