Foreign Key's do not require unique constraint

[Brian Aker]

From the MySQL manual:
"Additionally, MySQL and InnoDB require that the referenced columns be indexed for performance. However, the system does not enforce a requirement that the referenced columns be UNIQUE or be declared NOT NULL. The handling of foreign key references to nonunique keys or keys that contain NULL values is not well defined for operations such as UPDATE or DELETE CASCADE. You are advised to use foreign keys that reference only UNIQUE and NOT NULL keys."

This is a bug, not a feature, that was never fixed. We should fix it.

[Akash Sinha (sinha)]

I would like to work on this thing..how should i start ?

[Andrew Hutchings (linuxjedi)]

Please see the documentation on contributing code at: http://docs.drizzle.org/contributing/code.html#code-label

If you have any questions please let us know.