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Equivalence Rules (Cont.) 7.The selection operation distributes over the theta join operation under the following two conditions: (a)When all the attributes in 00 involve only the attributes of one of the expressions(E)being joined. oo(E1☒6E2)=(oo(E1)凶gE2 (b)When01 involves only the attributes of E1 and 02 involves only the attributes of E2. o91N2(E1凶9E2)=(o1(E1)凶(o2(E2) Database System Concepts-6th Edition 1.11 @Silberschatz,Korth and SudarshanDatabase System Concepts - 6 1.11 ©Silberschatz, Korth and Sudarshan th Edition 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 ))
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