Suppose blocks hold either three records, or ten key-pointer pairs. As a function of n, the...

Question:

Suppose blocks hold either three records, or ten key-pointer pairs. As a function of n, the number of records, how many blocks do we need to hold a date file and: (a) A dense index (b) A sparse index?

Indexing:

The index is used for searching the data. Index tooks the value of the field and searches the matching data. Indexes of three types: sequential files, dense index, sparse index.

Answer and Explanation: 1

A) Dense index:

The number of records=n

a number of record per data block=3

number of data block used = n/3

number of indexes = n/10

Total data and index= n/3+n/10=13n/30

B) Sparse index:

The number of records=n

a number of record per data block=3

number of data block used = n/3

number of indexes = n/3/10 =n/30

total data and index = n/30+n/3=11n/30.


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What is a Database Index? - Definition & Tutorial

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Chapter 6 / Lesson 10
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Take a look into the definition of a database index, a comparison of spreadsheets and database indexes, a full-text search engine comparison, a tutorial of database index types, and some categories of database indexes.


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