However, if primary key information isn't specified in your database server's schema information (as with Microsoft Access), the wizard now asks you to specify a primary key for each entity.
MovieRole's primary key is compound; that is, it's composed of more than one attribute. Use a compound primary key when any single attribute isn't sufficient to uniquely identify a row. For MovieRole, the combination of the movieId and talentId attributes is guaranteed to uniquely identify a row.
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