Re: Question: unique on multiple columns
От | Arjen van der Meijden |
---|---|
Тема | Re: Question: unique on multiple columns |
Дата | |
Msg-id | 001d01c2cd1e$fa0352f0$3ac15e91@acm обсуждение исходный текст |
Ответ на | Question: unique on multiple columns (roverr <roverr@dogpound.is-a-geek.org>) |
Список | pgsql-general |
How about a unique index. Create unique index table_col2_col3_unique ON table (col2, col3); > -----Oorspronkelijk bericht----- > Van: pgsql-general-owner@postgresql.org > [mailto:pgsql-general-owner@postgresql.org] Namens roverr > Verzonden: woensdag 5 februari 2003 12:47 > Aan: pgsql-general@postgresql.org > Onderwerp: [GENERAL] Question: unique on multiple columns > > > I'm running postgresql 7.2.1. > Is there a way to specify a constraint such that the > combination of two columns in a table is unique? > > I have a table as follows: > col 1: id, type serial, primary key > col 2: host_id, type integer, foreign key to hosts table > col 3: data_time, type timestamp > col 4 - 9 data that is unique to col 2 and 3 > > I wish to have a constraint such that the combination > of the host_id entry in col 2 and each data_time entry > in col 3 must be unique. > My thoughts are to calculate a new column based on > col 2 and 3 and force that to be unique. Is this > the correct approach or is my table layout hopelessly > flawed? > > Thanks in advance, > Gary > > > ---------------------------(end of > broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > http://www.postgresql.org/users-lounge/docs/faq.html
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