SQL access query- Update row if exists, insert if does not

Question

I need to write an SQL query for MS Access 2000 so that a row is updated if it exists, but inserted if it does not.

i.e.

If row exists...

UPD         


        

Answer 1

This doesn't apply directly to Access [EDIT: David-W-Fenton asserts that this is not possible in access], but for completeness (in case someone reading this is interested in something beyond Access):

I have had success in Microsoft SQL Server using an approach that should be more efficient as it only has to do one index check, rather than two. Here's an example from my current project:

UPDATE ActivityRelationships
SET [Count] = ([Count] + 1)
WHERE ActivityBeforeId=@activityBeforeId AND ActivityAfterId=@activityAfterId
IF @@ROWCOUNT=0
    INSERT INTO ActivityRelationships ([ActivityBeforeId], [ActivityAfterId], [Count])
    VALUES (@activityBeforeId, @activityAfterId, 1)