I found the following script

UPDATE RDB$RELATION_FIELDS
SET RDB$NULL_FLAG = 0
WHERE RDB$RELATION_NAME = 'EMPLOYEE'
AND RDB$FIELD_NAME = 'LAST_NAME';


It seemd to run ok and when looking with IBAdmin, it shows that column LAST_NAME is nullable.
But when I try to insert some values FB still says "validation error, column is null"?

Riho-Rene Ellermaa
senior programmer
Hansabank