maria-discuss team mailing list archive

[Roberto Spadim <roberto@xxxxxxxxxxxxx>]

that's the point, i think aria have a log before commit, and myisam commit
at everychange
must check, maybe the only possible method is transactional or aria, i will
try


2014-06-12 0:57 GMT-03:00 Pavel Ivanov <pivanof@xxxxxxxxxx>:

> I think you need to explain better what the big task is. This
> particular problem is solved with this:
>
> update test set other = case
>   when other = 'a' then 'b'
>   when other = 'b' then 'a'
> end;
>
> I wonder though how would this be different from two different updates
> if MySQL gets interrupted after updating one row, but before updating
> the second one. Or if it successfully updates first row, but gets some
> error with the second one. MyISAM/Aria can't rollback the first row,
> can it?
>
> On Wed, Jun 11, 2014 at 8:48 PM, Roberto Spadim <roberto@xxxxxxxxxxxxx>
> wrote:
> > ok it with a innodb/transactional table
> > what about a aria/myisam/connect/federated table?
> >
> >
> > 2014-06-12 0:45 GMT-03:00 Pavel Ivanov <pivanof@xxxxxxxxxx>:
> >
> >> On Wed, Jun 11, 2014 at 8:32 PM, Roberto Spadim <roberto@xxxxxxxxxxxxx>
> >> wrote:
> >> > Guys, i'm with a "newbie" question
> >> > I need to swap a primary key value, for example:
> >> > create table test (
> >> >  id int not null default 0,
> >> >   other varchar(255) not null default '',
> >> >  primary key(id)
> >> > );
> >> > insert into test (1,'a');
> >> > insert into test (2,'b');
> >> >
> >> > now i want that (2,'b') becomes (1,'b') and (1,'a') becomes (2,'a')
> >> >
> >> > the point is, how to do this, with only one UPDATE without duplicate
> >> > column
> >> > id value? and without delete values?
> >>
> >> How about this:
> >>
> >> begin;
> >> update test set other = 'b' where id = 1;
> >> update test set other = 'a' where id = 2;
> >> end;
> >
> >
> >
> >
> > --
> > Roberto Spadim
> > SPAEmpresarial
> > Eng. Automação e Controle
>



-- 
Roberto Spadim
SPAEmpresarial
Eng. Automação e Controle