I don't see implementation of "CHECK" CONSTRAINTS in the TODO list (e.g.
CONSTRAINT val_ck check (val >= 0 and val <=5)
Is this planned?
I do see FOREIGN KEY constraints on the 4.0 list, so there is a way to do
this kind of checking once this is implemented:
* Create an associated "range-check" table with a primary key column, and
add rows for the values you want to allow in your table column.
* Put a foreign key constraint on your column to point at that table.
This will at least ensure that you get a constraint violation if you attempt
to insert something illegal.
This works only for small ranges or other enumeration types (integer or
string). E.g.
create table check_phase_number (phase integer);
insert into check_phase_number values (1),(2),(3),(4),(5);
create table check_state_abbrev (state char(2));
insert into check_state_abbrev values ('AK'),('AL'),('CA'), ...
('VT'),('WA');
create table my_state_migration (
phase integer constraint phase_fk foreign key references
check_phase_number(phase),
state char(2) constraint state_fk foreign key references
check_state_abbrev(state),
...
);
-----Original Message-----
From: Cal Evans [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, March 20, 2001 8:27 AM
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: RE: Second Request - Limit Filed Input
you can use either an ENUM or a SET. Other than that, no.
Cal
http://www.calevans.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, March 20, 2001 10:05 AM
To: [EMAIL PROTECTED]
Subject: Second Request - Limit Filed Input
Is there a way in MySQL to limit the values that a (numeric) field can hold.
For example if I want a given field to only have the values 1 - 10 can I do
this and can it be done in the definition of the field when the table is
created?
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