Equivalence Rules (Cont.) 7.The selection operation distributes over the theta join operation under the following two conditions: (a)When all the attributes in 0o involve only the attributes of one of the expressions (E1)being joined. 0(E1E2)=(o0(E1)凶gE2 (b)When 0 1 involves only the attributes of E1 and 02 involves only the attributes of E2. o1N2(E1凶E2)=(o1(E1)Xg(o2(E2) Database System Concepts-5th Edition,Oct 5,2006. 14.11 ©Silberschat乜，Korth and SudarshanDatabase System Concepts - 5 14.11 ©Silberschatz, Korth and Sudarshan th Edition, Oct 5, 2006. Equivalence Rules (Cont.) 7. The selection operation distributes over the theta join operation under the following two conditions: (a) When all the attributes in 0 involve only the attributes of one of the expressions (E1 ) being joined. 0 (E1  E2 ) = (0 (E1 ))  E2 (b) When  1 involves only the attributes of E1 and 2 involves only the attributes of E2 . 1 (E1  E2 ) = (1 (E1 ))  ( (E2 ))