Hi all,
the 8.0 manual says CHECK can be used in the following manner:
CHECK (expression)
The only stipulations are that it must produce a boolean result (true or unknown) to succeed.

If I were to specify a the following on a field named price in one expression, would it succeed?
CHECK (price = 1 OR price = 2 OR price = 3)

In other words, I would want to raise an exception on any other value other than 1, 2, or 3. Can
this be done? All of the examples in the manual show a single check (like price > 0) .

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On Fri, Apr 22, 2005 at 12:02:41 -0400,
"Van Ingen, Lane" <lvaningen@ESNCC.com> wrote:
> Hi all,
> the 8.0 manual says CHECK can be used in the following manner:
> CHECK (expression)
> The only stipulations are that it must produce a boolean result (true or unknown) to succeed.
>
> If I were to specify a the following on a field named price in one expression, would it succeed?
> CHECK (price = 1 OR price = 2 OR price = 3)
>
> In other words, I would want to raise an exception on any other value other than 1, 2, or 3. Can
> this be done? All of the examples in the manual show a single check (like price > 0) .

Yes, you can do that.

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On Fri, Apr 22, 2005 at 12:02:41PM -0400, Van Ingen, Lane wrote:
>
> If I were to specify a the following on a field named price in one
> expression, would it succeed?
> CHECK (price = 1 OR price = 2 OR price = 3)

What happened when you tried it? A simple test should answer the
question.

CREATE TABLE foo (
id serial PRIMARY KEY,
price integer NOT NULL CHECK (price = 1 OR price = 2 OR price = 3)
);

INSERT INTO foo (price) VALUES (1);
INSERT 0 1

INSERT INTO foo (price) VALUES (2);
INSERT 0 1

INSERT INTO foo (price) VALUES (3);
INSERT 0 1

INSERT INTO foo (price) VALUES (0);
ERROR: new row for relation "foo" violates check constraint "foo_price_check"

INSERT INTO foo (price) VALUES (4);
ERROR: new row for relation "foo" violates check constraint "foo_price_check"

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/

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