CHECK constraint in MySQL is not working

user_237383 0
Viewed 116637

First I created a table like

CREATE TABLE Customer (
  SD integer CHECK (SD > 0),
  Last_Name varchar (30),
  First_Name varchar(30)
);

and then inserted values in that table

INSERT INTO Customer values ('-2','abc','zz');

MySQL doesn't show an error, it accepted the values.

check-constraints mysql
8 Answers

MySQL 8.0.16 is the first version that supports CHECK constraints.

Read https://dev.mysql.com/doc/refman/8.0/en/create-table-check-constraints.html

If you use MySQL 8.0.15 or earlier, the MySQL Reference Manual says:

The CHECK clause is parsed but ignored by all storage engines.

Try a trigger...

mysql> delimiter //
mysql> CREATE TRIGGER trig_sd_check BEFORE INSERT ON Customer 
    -> FOR EACH ROW 
    -> BEGIN 
    -> IF NEW.SD<0 THEN 
    -> SET NEW.SD=0; 
    -> END IF; 
    -> END
    -> //
mysql> delimiter ;

Hope that helps.

user_2565060
user_939790

Check constraints are supported as of version 8.0.15 (yet to be released)

https://bugs.mysql.com/bug.php?id=3464

[23 Jan 16:24] Paul Dubois

Posted by developer: Fixed in 8.0.15.

Previously, MySQL permitted a limited form of CHECK constraint syntax, but parsed and ignored it. MySQL now implements the core features of table and column CHECK constraints, for all storage engines. Constraints are defined using CREATE TABLE and ALTER TABLE statements.

user_1657830

Update to MySQL 8.0.16 to use checks:

As of MySQL 8.0.16, CREATE TABLE permits the core features of table and column CHECK constraints, for all storage engines. CREATE TABLE permits the following CHECK constraint syntax, for both table constraints and column constraints

MySQL Checks Documentation

user_4799640
Related