Laravel Schema: Require at least one of four columns is not null - mysql

Question

I have a structure that looks like this:
Attribute Values Table
+----+-----------+---------------+-------------+-------------+
| id | option_id | integer_value | price_value | text_value |
+----+-----------+---------------+-------------+-------------+
| 1 | 4 | NULL | NULL | NULL |
| 2 | NULL | 24 | NULL | NULL |
| 3 | NULL | NULL | NULL | Lorem Ipsum |
| 4 | NULL | NULL | 30.50 | NULL |
+----+-----------+---------------+-------------+-------------+
(Some columns were removed for brevity)
But basically the type of the entry can either be a reference to a select option (option_id), or an integer value (integer_value), or a decimal value (price_value), or a text value (text_value). One of the omitted columns is attribute_id which corresponds to an entry that has an enum which stores which one of these four columns is it.
Is there any way to add a constraint in the Laravel schema that at least one of these four columns has to be non-null?

Answer 1

If you will always have only one of these column filled at any time I would recomend altering your schema to just two colums
Like
+----------+--------------+------------+
| id | value | type |
+----------+--------------+------------+
Where the value will always have a value and type will contain the 4 types that you have mentioned
ie: option_id, integer_value, price_value and text_value
This way its clean.
In laravel you cannot add the specified constraint. You must validate your input before insertion.
However if you really want to add a database level constraint you could try adding a trigger before each insert to validate your need using the DB::unprepared function on the table.
and the trigger could look like this (I have not tried this)
DB::unprepared("
DELIMITER $$
CREATE TRIGGER `foo`
BEFORE INSERT ON `table`
FOR EACH ROW
BEGIN
IF (
new.option_id IS NULL
AND new.integer_value IS NULL
AND new.price_value IS NULL
AND new.text_value IS NULL
)
THEN SIGNAL SQLSTATE '02000'
SET MESSAGE_TEXT = 'your message here';
END IF;
END$$
DELIMITER ;
");