Red CHECK constraints

CREATE TABLE t (
    birth_date INT,
    death_date INT,
    [ CONSTRAINT chk_a_b ] CHECK (birth_date < death_date OR death_date IS NULL)
);

The CONSTRAINT part is optional and is useful only to specify a name. Names are useful because they appear in error messages.

Mar 01 '19 22:03 federico-razzoli

::?CLASS.^add-constraint-check: { .birth-date < .death-date OR not .death-date.defined };

Or

::?CLASS.^add-constraint-check: chk_a_b, { .birth-date < .death-date OR not .death-date.defined };

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Mar 01 '19 22:03 FCO

Should it warn when using a driver of database that do not support CHECK

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Mar 01 '19 22:03 FCO

I was going to write "or. like SQLite, accept the check definition but don't actually do the check" only to discover that it actually does, which was somewhat of a pleasant surprise.

Mar 02 '19 08:03 jonathanstowe

SQLite do use it? I’m surprised! :)

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Mar 02 '19 09:03 FCO

Apparently https://www.sqlite.org/lang_createtable.html I'm of the habit of just assuming that for most things it will accept the definition but just not do anything with it.

Mar 02 '19 09:03 jonathanstowe

No actually it works as it should in SQLite. In MySQL prior to 8.0 and in MariaDB prior to 10.3 (or something like that) the CHECKs are not enforced.

Mar 03 '19 23:03 federico-razzoli