UNIFY’s Identity Broker keeps old attribute names (both connector and adapter), in the ‘CollectionKey’ SQL table.  The attribute’s name (‘Caption’ column) is a unique key in that table.

Even if you delete an attribute from every connector and adapter in Broker, it still keeps that attribute name record.  Even if you delete all data for the attribute!  It’s there for good, with whatever capitalisation you first used.

If you try to use that same attribute name with a different capitalisation (e.g. in an Rename adapter transformation) Broker does a case-sensitive search for that attribute name’s CollectionKey record and doesn’t find it (because the case doesn’t match).  So it tries to create one… but this fails because the SQL unique key for the Caption field is case insensitive!  The error is:

Violation of UNIQUE KEY constraint 'DF_CollectionKey_Caption'.
Cannot insert duplicate key in object 'dbo.CollectionKey'.
The duplicate key value is (xxxx).

Solutions to this predicament are:

1. Don’t ever change the capitalisation of the attribute name (avoidance)
2. If you have to change it (e.g. because you got it wrong in the first place) then go into the SQL table and change the Caption to whatever capitalisation you want 🙂