Re: unique & update
От | Frank Schafer |
---|---|
Тема | Re: unique & update |
Дата | |
Msg-id | 1012310744.320.20.camel@ADMIN обсуждение исходный текст |
Ответ на | unique & update ("Ben-Nes Michael" <miki@canaan.co.il>) |
Список | pgsql-general |
On Tue, 2002-01-29 at 13:38, Ben-Nes Michael wrote: > Hi All > > Im into SQL trees trying to work with CELKO way to do it: > http://www.intelligententerprise.com/001020/celko.shtml > > The problem is that if I try to add a new descendent which is not the most > right sibling I get UNIQUE error. > > This occur ( if im right ) when the update try to update the lft column > which is UNIQUE > > Example of table: > > CREATE TABLE areas ( > lft INT UNIQUE > ); O.K. ... we used a column constraint ... > I inserted 3 rows with value: 1, 2, 3 ... everything is unique, so all is fine ... > now im trying to update: > update areas set lft = lft +1; ... update works on the first row, so the table would be 2, 2, 3 ... > Then I get the UNIQUE problem. ... what is exectly what the unique constraint is for. > Is there a way to do UNIQUE check after the whole table got updated ? > If not, any ideas to walk around the problem ? Try: CREATE TABLE areas ( UNIQUE ( lft ), lft INT ); Then we have a table with a table constraint. I'm only guessing ( using ``\h CREATE TABLE'' on the psql prompt ) and I'm a PostgreSQL -- and in fact SQL -- newbie, but if I'm interpreting the syntax diagram and MY mind about these constraints right, this should do what you need. Regards Frank
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