Not sure if I’m getting the correct error message or why I can’t add a unique constraint:

Invalid insert or update value(s): object columns are constrained - no 2 table rows can have duplicate column values.

attempt to store duplicate value (visible to active transactions) in unique index "UNQ_ERSWORKTYPE".

Now I know the values in the field in question are unique – I have only 3 records.

But when I delete all the records from the table, I still get the above message.

So this message appears not to relate to the constraint but instead to the RBD$INDICES insert. But the name of the UNQ_ index is not already taken. Indeed, I have tried several other names. I have only a handful of unique indexes anyway and can see no conflict.

Does anyone have a hint as to why an empty table should not accept and unique constraint with an index name which does not already exist?

Regards

Alan McDonald