Data Mgmt Lab_Part_37 - Hash-Based Indexing 109 4 Example 1...

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Hash-Based Indexing 109 4. Example 1: Consider a situation in which the number of records in the Fle is constant and only equality selections are performed. Static hashing requires one or two disk accesses to get to the data entry. ISAM may require more than one depending on the height of the ISAM tree. Example 2: Consider a situation in which the search key values of data entries can be used to build a clustered index and most of the queries are range queries on this Feld. Then ISAM deFnitely wins over static hashing. 5. Example 1: Again consider a situation in which only equality selections are performed on the index. Linear hashing is better than B+ tree in this case. Example 2: When an index which is clustered and most of the queries are range searches, B+ indexes are better. Exercise 11.6 Give examples of the following: 1. A Linear Hashing index and an Extendible Hashing index with the same data entries, such that the Linear Hashing index has more pages. 2. A Linear Hashing index and an Extendible Hashing index with the same data entries, such that the Extendible Hashing index has more pages. Answer 11.6 Answer omitted. Exercise 11.7 Consider a relation R( a, b, c, d ) containing 1 million records, where each page of the relation holds 10 records. R is organized as a heap Fle with unclustered
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This note was uploaded on 01/17/2012 for the course EGN 4302 taught by Professor Dr.vishak during the Fall '12 term at University of Central Florida.

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Data Mgmt Lab_Part_37 - Hash-Based Indexing 109 4 Example 1...

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