cs186_sp08_mt2 4

cs186_sp08_mt2 4 - AND DueDate>Now; Assume “Now” is...

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2. Query processing (18 points) Consider the following schema: LibraryBooks(ISBN, Title, Author, Branch) Patrons(CardNumber, Name, Address, City, State, ZipCode) CheckedOut(CardNumber, ISBN, DueDate) a. The DBMS optimizer is considering two plans for the following query: SELECT Title, Author, Name FROM LibraryBooks, Patrons, CheckedOut WHERE LibraryBooks.ISBN = CheckedOut.ISBN AND Patrons.CardNumber = CheckedOut.CardNumber AND Branch=’Central’
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Unformatted text preview: AND DueDate>Now; Assume “Now” is a special value that always evaluates to, well, now. The two plans are: LibraryBooks Patrons CheckedOut NestedLoopJoin NestedLoopJoin Selection (DueDate>Now) Projection(Title,Author,Name) Selection (Branch=Central) Plan A LibraryBooks Patrons CheckedOut NestedLoopJoin NestedLoopJoin Selection (DueDate>Now) Projection(Title,Author,Name) Selection (Branch=Central) Plan B...
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This note was uploaded on 08/30/2009 for the course CS 186 taught by Professor Staff during the Spring '08 term at Berkeley.

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