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Secondary Index

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Submitted By HusseinAlamery
Words 2595
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Abstract—A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of slower writes and increased storage space. This paper describes data indexes in database management system and the types of data indexes and how the data organized. It focuses on the secondary index in the database and a secondary index on a non key field implemented.
Index Terms—Database Indexes, Indexes, Secondary Indexes. (keywords)

database system would look up an index to find on which disk blocks the corresponding record resides, and then fetch the disk block, to get the account record. Keeping a sorted list of account numbers would not work well on every large databases with millions of accounts, since the index would itself be very big; further, even through keeping the index sorted reduces the search time, finding an account can still be further time-consuming. Instead, more

I. Introduction

An index for a file in a database system works in much the same way as the index in any normal books. If we want to learn a particular topic (described by a word or phrase) in this book, we can search for the topic in the index at the back of the book, find the pages where it occurs, and then read the pages to find the information we are looking for. The words in the index are in sorted order, making it easy to find the word we are looking for. Moreover, the index much smaller than the book, further reducing the effort needed to find the word we are looking for [1]. Database-system indices play the same role as a book index in the libraries. For example, to retrieve an account record given the account number, the

sophisticated indexing techniques may be used [2]. We shall discuss one of these techniques in this paper .

II. Indexes

An index is a small table having only two columns. The first column contains a copy of the

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