Subject Re: [ib-support] Changing a column from NULLable to NOT NULL
Author Martijn Tonies

No, this is not possible via standard DDL. InterBase Workbench and
Firebird Workbench both do this by directly updating the system tables.

NOT NULL to NULLable involves two actions while changing from
NULL to NOT NULL involves only 1 and only works for not-domain
related fields.

RDB$FIELDS holds all field definitions and has a column NULL_FLAG.

Or download Firebird Workbench :)

With regards,

Martijn Tonies
InterBase Workbench - the developer tool for InterBase

Firebird Workbench - the developer tool for Firebird

Upscene Productions

"This is an object-oriented system.
If we change anything, the users object."

> I would like to change a column in a table from NULLable to NOT NULL.
> >From looking at the Interbase 6 SQL Reference, and searching for help on
> internet, it would appear you cannot do this.
> Is the only way to do this is to create a new column as not null, copy the
> field data from the old column to the new column, delete the old column
> rename the new column to the old column name?
> If there is a way you can use ALTER TABLE..... please let me know. If not
> could you confirm that the above is true?
> Thanks,
> Stephen