A primary key or unique constraint must be defined for table '<0s>' before it can participate in a relationship.
In order to create a foreign key relationship, at least one of the two tables must have a primary key or unique constraint defined.
To create the relationship you are attempting to create, first create a primary key for one of the tables.
| Creating and Modifying PRIMARY KEY Constraints | Key Object |
| Creating and Modifying UNIQUE Constraints | Primary Key Constraints |