Lecture3 - EMP1 ENO ENAME TITLE E1 J. Doe Elec. Eng E3 A....

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Question Given relation EMP as in Figure 5.3 of Ozsu-Valduriez, let p1: TITLE < "Programmer" and p2: TITLE > "Programmer" be two simple predicates. Assume that character strings have an order among them, based on the alphabetical order. o Perform a horizontal fragmentation of relation EMP with respect to {p1, p2} o Explain why the resulting fragmentation (EMP1, EMP2) does not fulfill the correctness rules of fragmentation. Not fragmented or original relation EMP ENO ENAME TITLE E1 J. Doe Elec. Eng E2 M. Smith Syst. Anal. E3 A. Lee Mech. Eng. E4 J. Miller Programmer E5 B. Casey Syst. Anal. E6 L. Chu Elec. Eng E7 R. Davis Mech. Eng. E8 J. Jones Syst. Anal.
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Unformatted text preview: EMP1 ENO ENAME TITLE E1 J. Doe Elec. Eng E3 A. Lee Mech. Eng. E6 L. Chu Elec. Eng E7 R. Davis Mech. Eng. EMP2 ENO ENAME TITLE E2 M. Smith Syst. Anal. E5 B. Casey Syst. Anal. E8 J. Jones Syst. Anal. According to the rule of completeness, if the relation R is divided into fragments, then every data item in R should exist in at least one fragment. In our case, the relation EMP is fragmented into EMP1 and EMP2 based on the rule defined above. A record for employee E4 (with title=Programmer) is neither in EPM1 nor in EMP2. Hence, this fragmentation doesnt fulfill the completeness rule....
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