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Re: [GENERAL] Constraint + where - Mailing list pgsql-general

From Melvin Davidson
Subject Re: [GENERAL] Constraint + where
Date
Msg-id CANu8Fiz77HzbXXqLrdU3G8FZN5WtJd7KYWnM5LmrphdgxBOkUA@mail.gmail.com
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In response to Re: [GENERAL] Constraint + where  (Melvin Davidson <melvin6925@gmail.com>)
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On Sun, Mar 19, 2017 at 8:27 PM, Melvin Davidson <melvin6925@gmail.com> wrote:


On Sun, Mar 19, 2017 at 8:16 PM, Patrick B <patrickbakerbr@gmail.com> wrote:
Hi guys,

I've got a column 'type_note' on a new table that it's being designed:

type_note varchar(32) NOT NULL;

On that column, there will be three different data:

1. yes
2. no
3. maybe

I wanna create a FK but just when the data on that column is = maybe.

How can I do that? Thanks!


Why just "maybe"? Since there can only be three valid answers, why not FK for all three?

--
Melvin Davidson
I reserve the right to fantasize.  Whether or not you
wish to share my fantasy is entirely up to you.

Also "type_note varchar(32) NOT NULL;" is pointless.
You should make it either type_note(1)  with values of Y,N or M.


--
Melvin Davidson
I reserve the right to fantasize.  Whether or not you
wish to share my fantasy is entirely up to you.

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