Thank you very much Alan, your explanation was very clear.

Greetings.

Walter.

On Mon, Jan 7, 2013 at 8:51 PM, Alan McDonald <alan@...> wrote:

> **
>
>
> > Thank you very much Alan for your answer.
> >
> > How do you use dummy updates, can explain me more about that
> > technique?
> >
> > Greetings.
> >
> > Walter.
> >
>
> If you get the Firebird book you will have a complete explanation. You need
> to understand transaction settings little better.
> In short, if you issue 'UPDATE TABLE SET PKID=PKID where PKID=:PKID'
> You will either succeed, in which case you can proceed under that same
> transaction to edit/update the row and commit, OR you will fail, in which
> case you alert the user that someone else is editing, come back later.
> I also save the username of the user who succeeds so I can tell the other
> person who it is that actually has the record in an edit state.
> Alan
>
>
> >
> >
> >
> >
> > On Mon, Jan 7, 2013 at 6:32 PM, Alan McDonald alan@...> wrote:
> >
> > > **
>
> > >
> > >
> > > If 526 commits, then 535 will need to re-acquire before a successfull
> > > update, If 526 rolls back, then 535 could proceed with existing
> > > 'stalled' edits but the WAIT option is clumcy for the user... there's
> > > no way of knowing how long they have to wait.
> > > I repeat, you are better off preventing 535 from starting the update
> > > until it is assured it will succeed. i.e. by obtaining an edit lock. I
> > > use dummy updates to ensure the edit/lock is possible Alan
> > >
> > > On Tue, Jan 8, 2013 at 8:32 AM, W O sistemas2000profesional@...
> > > >wrote:
> > >
> > >
> > > > - Transaction 510 inserts a new row
> > > > - Transaction 510 commits
> > > > - Transaction 526 start
> > > > - Transaction 526 updates the row inserted by transaction 510
> > > > - Transaction 535 start, with the clause WAIT
> > > > - Transaction 535 wants to update the row inserted by transaction
> > > > 510 but unsuccessfully because it is locked by transaction 526
> > > > - Transaction 526 commits
> > > > - Transaction 535 can now update the row inserted by transaction
> > > > 510? or neither with the clause WAIT can do that?
> > > >
> > > > Greetings.
> > > >
> > > > Walter.
> > > >
> > > >
> > > > [Non-text portions of this message have been removed]
> > > >
> > > >
> > > >
> > > > ------------------------------------
> > > >
> > > >
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > ++++++++
> > > >
> > > > Visit http://www.firebirdsql.org and click the Resources item on the
> > > > main (top) menu. Try Knowledgebase and FAQ links !
> > > >
> > > > Also search the knowledgebases at http://www.ibphoenix.com
> > > >
> > > >
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > ++++++++
> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > >
> > > --
> > > regards
> > > Alan McDonald
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> > ------------------------------------
> >
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > ++++++++
> >
> > Visit http://www.firebirdsql.org and click the Resources item on the
> main
> > (top) menu. Try Knowledgebase and FAQ links !
> >
> > Also search the knowledgebases at http://www.ibphoenix.com
> >
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > ++++++++
> > Yahoo! Groups Links
> >
> >
> >
>
>
>


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