In what situation can we use the following rule when optimizing queries? Please also explain why...
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In what situation can we use the following rule when optimizing queries? Please also explain why we use this rule. Oc( R*S ) = (0 c1 (R))*(0 c2 (S)) Consider the relations: STUDENT(SNAME, SID, BDATE, ADDRESS, DNUM) COURSE(CNAME, CID, LEVEL, LECTURER) COURSE TAKING(STUDENTID, COURSEID, GRADE) as well as the following SQL query: SELECT SNAME, CNAME, GRADE FROM STUDENT, COURSE TAKING, COURSE WHERE LEVEL 2 AND STUDENTID-SID AND COURSEID-CID AND DNUM=24; a) Draw a canonical query tree for the above SQL query. b) Apply the optimization rules to the above query tree and come up with the most optimized query tree using those rules. State the necessary assumptions for your decision. In what situation can we use the following rule when optimizing queries? Please also explain why we use this rule. Oc( R*S ) = (0 c1 (R))*(0 c2 (S)) Consider the relations: STUDENT(SNAME, SID, BDATE, ADDRESS, DNUM) COURSE(CNAME, CID, LEVEL, LECTURER) COURSE TAKING(STUDENTID, COURSEID, GRADE) as well as the following SQL query: SELECT SNAME, CNAME, GRADE FROM STUDENT, COURSE TAKING, COURSE WHERE LEVEL 2 AND STUDENTID-SID AND COURSEID-CID AND DNUM=24; a) Draw a canonical query tree for the above SQL query. b) Apply the optimization rules to the above query tree and come up with the most optimized query tree using those rules. State the necessary assumptions for your decision.
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2 c c1 c2 cn in join operation to reduce the size of tables which are participating ... View the full answer
Related Book For
Microeconomics An Intuitive Approach with Calculus
ISBN: 978-0538453257
1st edition
Authors: Thomas Nechyba
Posted Date:
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