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Unformatted text preview: Homework 2 CSE 132A Due by noon on Monday, Dec. 8, by sliding under Alins office door. Problem 2 [20pts] Suppose that a B + tree index on (branch-name, branch- city) is available on relation branch . What would be the best way to handle the following selection? ( branch- city&lt; Brooklyn 00 ) ( assets&lt; 5000) ( branch- name = 00 Downtown 00 ) ( branch ) Solution: Assume that the index compares keys lexicographically, with the brach-name as the most significant component: ( n 1 , c 1 ) &lt; ( n 2 , c 2 ) iff c 1 &lt; c 2 or ( c 1 = c 2 and n 1 &lt; n 2 ) . Lookup the value (Brooklyn,Downtown) in the index, to get to the corresponding leaf l . All values satisfying ( branch- city&lt; Brooklyn 00 ) ( branch- name = 00 Downtown 00 ) ( branch ) are reachable by going to the left sibling leaves of l as long as the branch-name attribute is Downtown. For each visited leaf, output only if assets &lt; 5000....
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This note was uploaded on 12/03/2009 for the course CSE 132A taught by Professor Alindeutsch during the Fall '08 term at UCSD.
- Fall '08