Thanks, Helen.

I know the questions have come up multiple times; no matter what the
search I couldn't find the posts with the answers in them. Maybe I'm
getting too old...

Lee

--- In firebird-support@yahoogroups.com, Helen Borrie <helebor@...> wrote:
>
> At 12:05 PM 25/02/2008, you wrote:
> >I can't believe there isn't a way to do this...
>
> 'course there is.
>
>
> >--- In firebird-support@yahoogroups.com, "Lee" <waywardwretch@> wrote:
> >>
> >> What is the best/easiest way to change...
>
> > (B) a BLOB field's subtype from TEXT to BINARY?
>
> alter table mytable
> alter myblob type blob sub_type 0
> or
> alter table mytable
> alter myblob type blob sub_type binary
>
> This doesn't change data, of course, since the engine neither knows
nor cares what's in a blob. All you're doing here is removing the
association between your blob and the blob filter that underlies the
TEXT Blob, allowing some string functions to be applied to it.
>
> >>
> >> (A) a VARCHAR field's character set from ISO8859_1 to OCTETS?
> >>
>
> You happen to have an "easy" conversion here because you're going
varchar-to-varchar with single-byte characters. If you have no
COLLATE attribute on the current definition, it is as easy as this
(converting a varchar(20) for example):
>
> alter table mytable
> alter mycolumn varchar(20) type character set octets;
>
> If you do have a COLLATE on the column currently, do it like this:
>
> create domain dom_20_octets as varchar(20) character set octets
collate octets;
> commit;
>
> alter table mytable
> alter mycolumn type dom_20_octets;
>
> Note that it's not *this* easy converting char columns, or varchar
columns involving multi-byte character sets. So, although you weren't
asking about that, it's the kind of question people don't willingly
reply to unless they've got a lot of time on their hands....and it has
come up dozens of times in the list.
>
> ./heLen
>