SQL Antipatterns, Volume 1

Solution: Declare Constraints

The Japanese phrase poka-yoke means “mistake proofing.” Poka-yoke was coined by industrial engineer Dr. Shigeo Shingo in his study of the Toyota Production System. This term refers to a manufacturing process that helps eliminate product defects by preventing, correcting, or drawing attention to errors as they occur. This practice improves quality and decreases the need for correction, which more than makes up for the cost of its use.

You can apply the poka-yoke principle to your database design by using foreign key constraints to enforce referential integrity. Instead of searching for and correcting data integrity mistakes, you can prevent these mistakes from entering your database in the first place.

Keyless-Entry/soln/foreign-keys.sql ...