I guess you could find it out by first trying to cast the old value to the new, e.g.:

SELECT CAST(TheColumn AS VARCHAR(400)) FROM TheTable;

Or in your example:

SELECT CAST(TheColumn AS BLOB SUB_TYPE 1 SEGMENT SIZE 100) FROM TheTable;

Which will not work, as far as I know. Only way to persist your data would be to add a second column with the blob type, and copy the data with an UDF, and drop the old column afterwards.

Cheers

> -----Ursprüngliche Nachricht-----
> Von: Ed Dressel [mailto:dressel@...]
> Gesendet: Montag, 21. März 2005 19:45
> An: firebird-support@yahoogroups.com
> Betreff: [firebird-support] altering a domain
>
>
>
> I have a column associated with a domain defined as
> 'VARCHAR(200) CHARACTER SET NONE' and want to assign it to a
> domain defined as 'BLOB SUB_TYPE 1 SEGMENT SIZE 100'. Is that
> allowed, ie will my current data persist? (Is there any way
> of knowing what is/isn't allowed?).
>
> Ed Dressel
>
>
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>
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