I fount nothing inside the XF Scripts. If I create e DataWriter for a table, that has a colum in which can stored NULL. How can I Update a row and change the value to NULL? During Insert, the defautl value ist NULL and I simple did not set the value, but If I set the Valur to NULL with the datawriter, I got an SQL Error. On this Field I created an ForeignKey with NULL allowed. Change the Value per Query direct in he dabase works. The same error occurs, If one try inside the referencing table has the key 0 and I want to write that.