Re: create table with multiple unique fields
От | steve boyle |
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Тема | Re: create table with multiple unique fields |
Дата | |
Msg-id | a1c622$13qg$1@news.tht.net обсуждение исходный текст |
Список | pgsql-sql |
Karl, you can either set the Primary key over all 3 fields to ensure uniquenes i.e: create table warehouse ( warehouseno int4, location varchar(3), productid varchar(1), primarykey (warehouseno, location, productid) ); or define a unique index over the 3 fields after the table has been defined: create table warehouse ( warehouseno int4, location varchar(3), productid varchar(1) ); create unique index idx on warehouse (warehouseno, location, productid); The difference between the two methods is that NULLS are not allowed in Primary Keys (method 1) but would be allowed using the unique index (method 2). Hope it helps Steve Boyle "Karl Raven" <lcaasia@pd.jaring.my> wrote in message news:a1agea$qap$1@news.tht.net... > > I'd like to create a table with 3 create unique fields : > > fields > warehouseno,loc, productid, qty, qtyalllocated > > i'd like warehouseno,loc, productid to be unique.. > meaning > 2000, ABC, X - ok > 2000,ABC,Y -ok > 2000,ABC,X - reject > 2000,BCD,X - ok > > anyone knows how to do so? > > thanks > >
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