designing a badge system, where to fire business logic? In code or stored procedures? or both? [closed]

Answer 1

I would write a stored procedure, since all the information needed resides in the database so this is the most efficient place to access that data.

A tyical rule could be implemented via a single INSERT statement along these lines:

IF eligible for  THEN
    INSERT INTO user_badges
    SELECT 
    WHERE NOT EXISTS (SELECT NULL FROM user_badges
                      WHERE badge = );
END IF;

(I simplify somewhat!)