MDB2 nextId will increase even with duplicate data

Hello,

I have a table ('table') with three columns: id (primary) , a_id, b_id.
The pair (a_id,b_id) is set as UNIQUE in the database.

I am using MDB2 (similar to DB) and I am making use of nextId. So I have table_seq as the table with the latest id.
When I want to enter new information (by the end of the call) I make table_seq increase its id. This is all good but this happens even if the pair being inserted in table is a duplicate and so wont be inserted.... yet still the table_seq is increased.

Any suggestions for improvement ?

Any comments or suggestions are more than welcome.

Thanks

Did you find any answer to this?
I am having a similar problem (as well as the first sequence value becoming '2', instead of '1')

Any advice would be great.

Thanks.