<p>Here is a nice underhand lob pitch to you guys.</p>

<p>So basically I've got my content table with unique primary key IDs and I've got my tag table with unique primary key IDs. </p>

<p>I've got a table that has an identity column as a primary key but the two other columes are the contentID and tagID.  What do I need to do to the table to make sure that I only have the same contentID and tagID combo only once.</p>

You put a Unique constraint on contentID, tagID.
For SQL Server
```
```
ALTER TABLE ContentTag ADD CONSTRAINT
    IX_ContentID_TagID_Unique UNIQUE NONCLUSTERED ( contentID,  tagID ) 
GO
```
```