Re: EVAL and SET equivalents in PostgreSQL

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От Alvaro Herrera
Тема Re: EVAL and SET equivalents in PostgreSQL
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Msg-id Pine.LNX.4.44.0207032303150.7246-100000@cm-lcon-46-187.cm.vtr.net
обсуждение исходный текст
Ответ на Re: EVAL and SET equivalents in PostgreSQL  (Bruce Momjian <pgman@candle.pha.pa.us>)
Ответы Re: EVAL and SET equivalents in PostgreSQL  (Stephan Szabo <sszabo@megazone23.bigpanda.com>)
Список pgsql-general
Bruce Momjian dijo:

> Sure, use CHECK constraints on the column.  That is the ANSI standard
> way.
>
>              gender    CHAR(1)      CHECK (gender IN ('M','F')),

That's the solution for the ENUM MySQL datatype, but the SET datatype
allows one to have multiple values in the column (or that's what I
understood in the original message).

In PostgreSQL, you could use an array to store multiple values.  I don't
know if one could set up a CHECK constraint so that every element in a
varchar array is checked against a predefined set.  Maybe it can be done
at insertion time using a trigger?

--
Alvaro Herrera (<alvherre[a]atentus.com>)
"Ninguna manada de bestias tiene una voz tan horrible como la humana" (Orual)




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