Hi all,

I'm trying to figure out how to drop NOT NULL column constraints.

I've looked up the constraint name via the RDB$RELATION_CONSTRAINTS table.
When I issue a 'alter table [table] drop constraint [constraint]', it
doesn't complain and the corresponding record in RDB$CHECK_CONSTRAINTS is
deleted as well.

However, when I issue a statement to insert a NULL into the column, it
fails, telling me that it should be NOT NULL.

I noticed that the RDB$NULL_FLAG in the RDB$RELATION_FIELDS is set to 0 and
the corresponding record in RDB$FIELDS has a NULL state for RDB$NULL_FLAG. I
changed the RDB$NULL_FLAG in RDB$RELATION_FIELDS to NULL, but that didn't
help... I still cannot insert NULLs into the column.

What do I have to do to get the field NULLable and how do I do the reverse
(NULLable to NOT NULLable).


Martijn Tonies
InterBase Workbench - the developer tool for InterBase and Firebird
http://www.interbaseworkbench.com








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