aria and myisam don't support
2014-06-12 1:27 GMT-03:00 Roberto Spadim <robe...@spadim.com.br>: > update test set id = case > when id = '1' then '2' > when id = '2' then '1' > end; > /* Erro SQL (1062): Duplicate entry '2' for key 'PRIMARY' */ > > > > 2014-06-12 1:26 GMT-03:00 Roberto Spadim <robe...@spadim.com.br>: > > 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 <piva...@google.com>: >> >> 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 <robe...@spadim.com.br> >>> 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 <piva...@google.com>: >>> > >>> >> On Wed, Jun 11, 2014 at 8:32 PM, Roberto Spadim < >>> robe...@spadim.com.br> >>> >> 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 >> > > > > -- > Roberto Spadim > SPAEmpresarial > Eng. Automação e Controle > -- Roberto Spadim SPAEmpresarial Eng. Automação e Controle
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