Relational Algebra

EXERCISE6 Consider the following relation R (A, B, c, D, E) Select which of the following projections have the same cardinality as R elation R (A, B, c, D,E) 1. PROJ A.B.cD R) 2. PROJ Ac (R) 3. PROJ B.c (R) 4. PROJ c (R) 5. PROJ c.D (R) C,D 21 EXERCISE7 1. PROJ A,B(R) 2. PROJ e (R2) 3. PROJB, ) Ri (3,0, ) , with IR,1-100 and a referential integrity constratin between C and R2 .R2 (D, E, F), with R22004. PROJ c(R3) and a referential integrity constratin between F and R2 R3 ( G, H, I), with |R3 50 Find the cardinality of the 6. R, JOINc-DR2 following expressions 23