0 if data is in sorted le do binary search to nd rst

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Unformatted text preview: ng techniques support both range searches and equality searches. •  ISAM: sta6c structure; B+ tree: dynamic, adjusts gracefully under inserts and deletes. Range Searches •  ``Find all students with gpa > 3.0’’ –  –  If data is in sorted file, do binary search to find first such student, then scan to find others. Cost of binary search can be quite high. •  Simple idea: Create an `index’ file. Page 1 Page 2 Index File kN k1 k2 Page 3   Can do binary search on (smaller) index file! Page N Data File index entry P 0 K 1 P 1 K2 P 2 Km Pm •  Index file may s6ll be quite large. But we can apply the idea repeatedly! Non-leaf Pages Leaf Pages Overflow page   Leaf pages contain data entries. Primary pages B+ Tree: Most Widely Used Index •  Insert/delete at log F N cost; keep tree height ­balanced. (F = fanout, N = # leaf pages) •  Minimum 50% occup...
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This document was uploaded on 03/12/2014 for the course CSCI 165B at UC Davis.

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