Alter Table Drop Column command

[Sandra J. Galvin]

I have a quick question that hopefully someone can answer. I altered a
table to add
a column and later discovered that it was causing problems for the
application. One
of the developers mentioned that there was a command to drop the table:

alter table drop <column_name>

I cannot find this command in any of the Sybase Manuals and was
wondering
if this is a supported command. If it is not, why is it available and
what does it do.

We seem to think that it drops the column from the syscolumns table but
leaves the data out there. If we were to use this command and then
later attempt to add that column back again what would happen?

I guess there are a few questions. If anyone has any information on
this, I would
greatly appreciate it.

Sandra

[Jason Froebe]

"Sandra J. Galvin" wrote:

Hi Sandra,

It is an undocumented & unsupported command in pre ASE 12. It will drop a
column from a table but may cause problems on these older versions (< 12).

Please post you question in sybase.public.sqlserver.general in the future
as the sybase.public.urgent_communications is for Sybase announcements.

j

[Bret Halford]

Hi Sandra,

This newsgroup is meant for urgent communications from Sybase to customers,

and follow-up discussions on those communications. Your question would be
more
appropriate in the "sybase.public.sqlserver.general" newsgroup - please
post there
in the future instead of here.

Alter table drop column is only supported and documented as of ASE version
12.0.

Earlier versions of the server do accept the syntax, but I strongly advise
you don't use it -
there were bugs with the command that can seriously corrupt your tables,
sometimes in
ways that do not become apparent for sometime. It is for that reason that
the command
has not been documented or supported in the past. I've always considered
it a bug that the
command wasn't locked out by the parser.

-bret

[Alan Ramsay]

"Bret Halford" <br...@sybase.com> wrote in message
news:38975775...@sybase.com...

> Hi Sandra,
>
> This newsgroup is meant for urgent communications from Sybase to
customers,

Well, please, please, please, please, please

(a) Tell customers to re-post in a different newsgroup to get the answer,
and don't tell them the answer until they do.
(b) Make it a 'read-only' newsgroup - It's not that difficult honest guv.

Alan

[Bret Halford]

Hi Alan,

Thanks for the comments. I'm not seeing a problem with people continuing to
post
to this newsgroup after its purpose has been explained, so I don't think the
kind
of "tough love" approach you suggest in (a) is necessary at this time, and we
do
prefer to get people their answer as soon as possible.

As for making this a read-only newsgroup, well, we would like people to have
a way
to respond to the urgent communications (ask for clarifications, etc.) which
is why
we don't do that.

-bret

[David Owen]

>>>>> "Bret" == Bret Halford <br...@sybase.com> writes:

Bret> Hi Alan, Thanks for the comments. I'm not seeing a problem with
Bret> people continuing to post to this newsgroup after its purpose has
Bret> been explained, so I don't think the kind of "tough love"
Bret> approach you suggest in (a) is necessary at this time, and we do
Bret> prefer to get people their answer as soon as possible.

Bret> As for making this a read-only newsgroup, well, we would like
Bret> people to have a way to respond to the urgent communications (ask
Bret> for clarifications, etc.) which is why we don't do that.

You could make it moderated though. I know that it would take a little bit
of someones time to check, but if you had an urgent communication of the
sort that this group is intended, then surely that person would be there to
do the moderation. All other communications would be sent to the bit
bucket.

Just a thought.

--
David Owen Midsomer Consultants Inc. do...@midsomer.org