no... I have a UniqueConstraint on a field called 'cve_unidad', this field has .AllowDBNull = true, and i put DefaultValue = null in this field, but, there is still a the problem... when i put two rows in then datagrid, the second null value raises the error message: "Value Column 'cve_unidad' is constrained to be unique. Value '' is already present. Do you want to correct this value?" this is a example: cve_unidad | nom_unidad (null) | 'un nombre' <-- here is ok (null) | 'another nombre' <-- here raises the "already present" error This is an "autonumeric-like" scenario, i want to send some values at once, then clear an refill the datagrid with the data (with de autonumeric updated). I don't want to use the .AutoIncrement properte beacuse the value displayed will not neccesary equals the autonumeric value in the database. thanks
