Project-Join Normal Form (PJNF) A relation schema R is in PJNF with respect to a set D of functional, multivalued,and join dependencies if for all join dependencies in D+of the form *(R1,R2,...,R where each RiR and R=RjUR2...URp at least one of the following holds: *(R1,R2,...,R)is a trivial join dependency. Every R,is a superkey for R. Since every multivalued dependency is also a join dependency. every PJNF schema is also in 4NF. Database System Concepts,5th Ed. C.8 ©Silberschat乜，Korth and SudarshanDatabase System Concepts, 5 C.8 ©Silberschatz, Korth and Sudarshan th Ed. Project-Join Normal Form (PJNF) A relation schema R is in PJNF with respect to a set D of functional, multivalued, and join dependencies if for all join dependencies in D+ of the form *(R1 , R2 ,..., Rn ) where each Ri  R and R =R1 R2  ...  Rn at least one of the following holds: *(R1 , R2 ,..., Rn ) is a trivial join dependency. Every Ri is a superkey for R. Since every multivalued dependency is also a join dependency, every PJNF schema is also in 4NF