Trigger UPDATE with ObjectPtr

[danhc at mail.dk]

O.K.

Thanks I will look forward to that

Kind regards
Dan

Ivan Smahin <ivan_smahin at paradigmasoft.com> wrote:

> Hello Ruslan,
> 
> Friday, January 18, 2008, 8:40:08 AM, you wrote:
> 
> > On 18/1/08 4:41 AM, "danhc at mail.dk" <danhc at mail.dk> wrote:
> 
> > Hi Dan,
> 
> >> Could You help me on this:
> >>
> >> How do I in SQL create a Trigger that on an update of 1 table
> updates
> >> records in an other table, but only the ones that have an
> ObjectPtr
> >> pointing back at the table containing the Trigger.
> >>
> >> I can't find out how to refer to the RecID og the Table containing
> the
> >> Trigger.
> >
> >> I am using Valentina 3.5.1 for RealBasic and Mac OSX 10.4.11
> 
> > You can Reffer RecID of updated record using
> 
> > NEW.RecID for BEFORE UPDATE trigger
> > OLD.RecID for AFTER UPDATE trigger
> 
> > It seems to me, you need use Stored Procedure to update records of
> linked
> > table. And call this procedure from trigger.
> 
> > Ivan ?
> 
> I would recommend to use sql from the very first steps...
> It is hard enough to read all that conditions in plain english...
> 
> Well, so you have:
> 
> CREATE TABLE t1 ( f1 LONG );
> CREATE TABLE t2 ( f1 LONG, ptr OBJECTPTR REFERENCES t1 );
> 
> INSERT INTO t1 VALUES (1);
> INSERT INTO t1 VALUES (2);
> 
> INSERT INTO t2 VALUES (0, 0);
> INSERT INTO t2 VALUES (0, 2);
> INSERT INTO t2 VALUES (0, 0);
> 
> --
> Assume we are updating t1.RecID == (1,2).
> Trigger should do some updates for t2.RecID == 2.
> Right?
> 
> It is simple - any ptr not-null and not-0 value means current record
> is linked to t1.
> 
> So:
> CREATE TRIGGER trigger1
> BEFORE UPDATE ON t1
> FOR EACH ROW
> BEGIN
> UPDATE t2 SET f1 = 1 WHERE ptr > 0;
> END;
> 
> --
> Assume we are updating t1.RecID == (1,2).
> But trigger should be fired for t1.RecID == 2 and do some updates for
> t2.RecID == 2.
> 
> So:
> CREATE TRIGGER trigger1
> BEFORE UPDATE ON t1
> FOR EACH ROW
> BEGIN
> UPDATE t2 SET f1 = NEW.RecID WHERE ptr = NEW.RecID;
> END;
> 
> Trying it I've found the bug. It would be fixed today and will be
> available in next beta.
> 
> --
> Best regards,
> Ivan Smahin
> Senior Software Engineer
> Paradigma Software, Inc
> Valentina - The Ultra-Fast Database
> http://www.valentina-db.com
> 
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