Обсуждение: Setting up Field constraints

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Setting up Field constraints

От
Joseph Maxwell
Дата:
Hello,
I have created a DB and TABLE but would like to constrain one field to
accept either "YES" or "NO" only. How can I set this up?
I have tried various syntactic constructs of

     Prior_Rx   varchar(3) NULL CHECK ('Yes', 'No'),
     Prior_Rx   varchar(3) NULL CHECK (VALUE 'Yes', 'No'),
     Prior_Rx   varchar(3) NULL CHECK ('Yes', 'No'),
     Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK (VALUE 'Yes', 'No')),
     Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK ('Yes', 'No')),
     Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK (VALUE Yes, No)),
     Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK (Yes, No)),
     Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK (Yes OR No)),
     Prior_Rx   varchar(3) NULL CHECK (Yes OR No),
     Prior_Rx   varchar(3) NULL CHECK ('Yes' OR 'No'),

Obviously they were all wrong, could someone advise?
Thanks

--  Joe  --
---------------------------------------------------------------------------------------
PS:
Just learned that the datatype should be 'bool' in this case

     haven't tested it yet

But had I wanted to restrict it to say either mike or john, or even one
of a list say, 'tea', 'coffee', 'chocolate' or 'espresso', how should
that be constructed?

Re: Setting up Field constraints

От
Stephan Szabo
Дата:
On Wed, 6 Mar 2002, Joseph Maxwell wrote:

> Hello,
> I have created a DB and TABLE but would like to constrain one field to
> accept either "YES" or "NO" only. How can I set this up?

Probably something like:
Prior_Rx varchar(3) CHECK (Prior_Rx in ('Yes','No'))

Re: Setting up Field constraints

От
Jeff Self
Дата:
Why not use a Boolean type?

On Wed, 2002-03-06 at 18:51, Joseph Maxwell wrote:
> Hello,
> I have created a DB and TABLE but would like to constrain one field to
> accept either "YES" or "NO" only. How can I set this up?
> I have tried various syntactic constructs of
>
>      Prior_Rx   varchar(3) NULL CHECK ('Yes', 'No'),
>      Prior_Rx   varchar(3) NULL CHECK (VALUE 'Yes', 'No'),
>      Prior_Rx   varchar(3) NULL CHECK ('Yes', 'No'),
>      Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK (VALUE 'Yes', 'No')),
>      Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK ('Yes', 'No')),
>      Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK (VALUE Yes, No)),
>      Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK (Yes, No)),
>      Prior_Rx   varchar(3) NULL CONSTRAINT (CHECK (Yes OR No)),
>      Prior_Rx   varchar(3) NULL CHECK (Yes OR No),
>      Prior_Rx   varchar(3) NULL CHECK ('Yes' OR 'No'),
>
> Obviously they were all wrong, could someone advise?
> Thanks
>
> --  Joe  --
> ---------------------------------------------------------------------------------------
> PS:
> Just learned that the datatype should be 'bool' in this case
>
>      haven't tested it yet
>
> But had I wanted to restrict it to say either mike or john, or even one
> of a list say, 'tea', 'coffee', 'chocolate' or 'espresso', how should
> that be constructed?
>
> ---------------------------(end of broadcast)---------------------------
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>
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--
Jeff Self
Information Technology Analyst
Department of Personnel
City of Newport News
2400 Washington Ave.
Newport News, VA 23607
757-926-6930