[DUG] Drop table in Interbase

[Jeremy Coulter]

yeah I know how to do it in code thats easy. I was just trying to do it in
SQL.
I am too used to MSSQL I guess :-)

On Wed, Jun 17, 2009 at 10:34 AM, Willie Juson <willie.Juson at satara.co.nz>wrote:

>  Here’s some quick and dirty code that works (it probably wants some
> exception handling added around the ExecSQL), but hopefully you get the gist
> of it, in this example the database DM.IBDBKiwitracker is a TIBDatabase
> component on our central Datamodule unit for our application. It assumes the
> Database has a default transaction assigned – which the TIBQuery gets in the
> absence of a specific one being assigned to it.
>
>
>
>
>
>
>
>
>
>
>
>   l_qry := TIBQuery.Create(nil);
>
>   try
>
>     l_qry.Database := DM.IBDBKiwitracker;
>
>     l_qry.Transaction.StartTransaction;
>
>     try
>
>       l_qry.SQL.Add('select count(*) from rdb$relations where
> Upper(RDB$RELATION_NAME) = (''MYTABLE'') ');
>
>       l_qry.Open;
>
>       if (l_qry.Fields[0].Asinteger > 0) then
>
>       begin
>
>         l_qry.Close;
>
>         l_qry.SQL.Clear;
>
>         l_qry.SQL.Add('drop table MyTable');
>
>         l_qry.ExecSQL;
>
>       end;
>
>     finally
>
>       if l_qry.Transaction.InTransaction then
>
>         l_qry.Transaction.Commit;
>
>     end;
>
>   finally
>
>     FreeAndNil(l_qry);
>
>   end;
>
>
>
>
>
> You might also want to check out a bit how the RDB$ tables work in
> interbase…..
>
>
>
>
>
> *From:* delphi-bounces at delphi.org.nz [mailto:delphi-bounces at delphi.org.nz]
> *On Behalf Of *Jeremy Coulter
> *Sent:* Wednesday, 17 June 2009 9:59 a.m.
> *To:* NZ Borland Developers Group - Delphi List
> *Subject:* Re: [DUG] Drop table in Interbase
>
>
>
> Thansk for your reply edward. However, I dont normall use Interbase and
> your example didnt make a lot of sence. I managed to find a similar example
> but I dont follow part of it.
>
> when I run :
>
> select * from rdb$relations WHERE RDB$RELATION_NAME = 'MyTable'
> and
> DROP TABLE MyTable;
> COMMIT;
>
> It tells me DROP is an invalid token. So I assume the "And" is not part of
> the SQL statement.
> So what I dont follow is, just doing a "SELECT" to see if a record exists
> then dropping the table seems like something is missing.
>
> in a programming sense, I would expect something like
>
> IF select * from rdb$relations WHERE RDB$RELATION_NAME = 'MyTable'  <> ''
> then
> DROP TABLE MyTable;
>
> I know thats not real code, but my point is, just because I can do a
> select, doesnt tell me if the table exists or not to try to delete
> it.......I hope you follow what I am meaning.
>
> Jeremy
>
>  On Tue, Jun 16, 2009 at 4:05 PM, John Bird <johnkbird at paradise.net.nz>
> wrote:
>
> For a good working example see
>
>
>
> http://xkcd.com/327/
>
>
>
> (Standard disclaimer - do not try this at home!)
>
>
>
> John
>
>
>
> ----- Original Message -----
>
>  *From:* Jeremy Coulter <jscoulter at gmail.com>
>
> *To:* NZ Borland Developers Group - Delphi List <delphi at delphi.org.nz>
>
> *Sent:* Tuesday, June 16, 2009 3:35 PM
>
> *Subject:* Re: [DUG] Drop table in Interbase
>
>
>
> ok cool I will try that.
>
> Thanks, Jeremy
>
> On Tue, Jun 16, 2009 at 2:54 PM, Edward Koryagin <ed_iv2001 at yahoo.co.nz>
> wrote:
>
>
> select * from rdb$relations ...
> and
> DROP TABLE ....
> Edward Koryagin
>
>
> --- On Tue, 16/6/09, Jeremy Coulter <jscoulter at gmail.com> wrote:
>
> > From: Jeremy Coulter <jscoulter at gmail.com>
> > Subject: [DUG] Drop table in Interbase
> > To: "NZ Borland Developers Group - Delphi List" <delphi at delphi.org.nz>
> > Received: Tuesday, 16 June, 2009, 1:31 PM
>
> > Hi all.
> > In interbase, how do I drop a table if it already exists?
> > I want to check for a table exists and if it does exist,
> > drop it.
> >
> > I have Googled, but I cant seem to find anything. I am
> > prob. searching wrong :-)
> >
> >
> > Jeremy
> >
> >
>
> > -----Inline Attachment Follows-----
> >
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>
>
>
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