Why have I received this “Error 1005: Can't create table... “?

MySQL server returns this error in the following cases:

• The referenced table is not an InnoDB table type;
• Other table contains the referenced field that is non-unique;
• Other table includes the referenced field with a dissimilar type to other id.

Note: In MySQL before v.5.0, the error also means that there is no index specified on the field id.