Secondary indexes, Database Management System

Assignment Help:

Secondary Indexes

Let consider the student database and its clustering index and primary (only one will be applicable at a time). Now consider the state when the database is to be searched or accessed in the alphabetical order of names. Any search on a student name would need sequential data file search, therefore, is going to be very time consuming. Such a search on an average would need reading of half of the total number of blocks.

Therefore, we require secondary indices in database systems. A secondary index is files that have records having a secondary index field value which is not the ordering field of the data file, and a pointer to the block that have the data record. Please note that even if a data file can have only single primary index (as there can be only single ordering of a database file), it can have many secondary indices.

Secondary index can be described on an alternate key or non-key attributes. A secondary index that is described on the alternate key will be dense as secondary index on non-key attributes would need a bucket of pointers for one index entry. Let us define them in more detail with the help of Figures.

                        828_Secondary Indexes.png


Related Discussions:- Secondary indexes

RAID technology, what characterizes the levels in RAID technology

what characterizes the levels in RAID technology

Equi-join, explain equi-join using illustration

explain equi-join using illustration

BCA, Ask qu. Write a XML with database with book details (Book ID, Title, A...

Ask qu. Write a XML with database with book details (Book ID, Title, Author, subject, published year, language, vendor, and price).estion #Minimum 100 words accepted#

Define what Immediate database modification technique uses, Define what Imm...

Define what Immediate database modification technique uses?  Ans: Both undo and redo.

The maximum no of key fields that can be used in a header, The Maximum no o...

The Maximum no of key fields that can be used in a header is?? 50

List the types of authorization, List the types of authorization. A) R...

List the types of authorization. A) Read authorization B) Write authorization C) Update authorization D) Drop authorization

Need database normalization and database analysis, Developer is required to...

Developer is required to do a task including: - Database Normalization - Database Analysis - ERM Diagram Details can be provided and then you can change your bid accord

Explain five duties of database administrator, Explain five duties of Datab...

Explain five duties of Database Administrator? 1. DBA administers the three stages of the database and, in consultation along with the whole user community, sets up an defin

Built online transaction processing, Question: A DBMS built for Online ...

Question: A DBMS built for Online Transaction Processing (OLTP) is generally regarded as unsuitable for data warehousing. Each system is designed with a different set of requir

What are the types of storage devices, What are the types of storage device...

What are the types of storage devices? Primary storage Secondary storage Tertiary storage Volatile storage Nonvolatile storage

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd