MySQL Foreign Key in Table in Another Database?

Is it possible to reference (Inn开发者_如何学编程oDB) a foreign key in another database in MySQL?

Is this bad practice?

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Yes, it's possible on the same DB server. Prefix the database name when adding the constraint, e.g. databasename.tablename.fieldname. Watch your user permissions.

I don't consider it bad practice, though it's not something that should be happening very often.

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Yes, You can use reference a foreign key in another database in MYSQL.

Thanks.