On Mon, Apr 4, 2016 at 2:10 PM, Peter Laursen <peter_laur...@webyog.com> wrote:
> As described in this Blog > http://mablomy.blogspot.dk/2016/04/check-constraint-for-mysql-not-null-on.html. > A very nice hack/trick IMO. > > However it is not working with MariaDB as VC's cannot be declared NOT > NULL. What prevents that? > > (Peter, sorry fro the previous private reply, not sure how I got the reply buttons wrong.) I can't answer that, but there's another workaround for (some) CHECK constraints, described here: http://dba.stackexchange.com/questions/9662/check-constraint-does-not-work/22019#22019 Unfortunately, it works only for smallish (int or date) ranges. We can't use for floats or decimals (as it would require a very big reference table). But it could be combined with the hack you link, using something like: CREATE TABLE truth (t BOOLEAN PRIMARY KEY) ; INSERT INTO truth (t) VALUES (TRUE) ; -- and remove all write permissions to the table CREATE TABLE checker ( i int, i_must_be_between_7_and_12 BOOLEAN AS (IF(i BETWEEN 7 AND 12, TRUE, FALSE)) PERSISTENT, CONSTRAINT check_i_must_be_between_7_and_12 FOREIGN KEY (i_must_be_between_7_and_12) REFERENCES truth (t) ); Haven't tested it but should work for more complex constraints as well. Pantelis
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