Security-data fragmentation, Database Management System

Assignment Help:

Security: Data not needed by local applications is not stored at the site, therefore no unnecessary security violations may exist.

But how can we carry out fragmentation? Fragmentation may be carried out as per the following rules:

a)      Completeness: This rule makes sure that there is no loss of data while fragmentation. If a relation is decomposed into fragments, then every data item must appear in at least single fragment.

b)      Reconstruction: This rule makes sure preservation of functional dependencies. It should be possible to describe a relational operation that will reconstruct the relation from its fragments.

c)       Disjointness: A data item that shows in a fragment should not show in any other fragment. Though, a typical fragmentation known as vertical fragmentation is an exception to this rule. In vertical fragmentation the primary key attributes must be repeated to permit reconstruction of original relation.

This rule makes sure minimization of data redundancy. What are the dissimilar types of fragmentation?

 


Related Discussions:- Security-data fragmentation

Explain nested relations, Explain nested relations? Nested relations ...

Explain nested relations? Nested relations The assumption of INF is a natural one in the bank examples we have considered. However, not all applications are best modelled

Project, the of super market system done in database

the of super market system done in database

Drop table command, DROP TABLE Command: When an existing object is not ...

DROP TABLE Command: When an existing object is not needed for further use, it is always better to eliminate it from the database. To remove the existing object from the databas

Data manipulation language, Data Manipulation Language Data manipulatio...

Data Manipulation Language Data manipulation language (DML) describes a set of commands that are used to query and change data within existing schema objects. In this case comm

Case snerio, each publisher has uniqe name a mial addrs are also kept on ea...

each publisher has uniqe name a mial addrs are also kept on each pubisher.a publisher publish one book.a book publish y one publisher.book identified by isbn.each book writn by one

List some security violations, List some security violations (or) name any ...

List some security violations (or) name any forms of malicious access. A) Unauthorized reading of data B) Unauthorized modification of data C) Unauthorized destruction of

Three levels of ANSI-SPARC architecture, a need some real life examples of...

a need some real life examples of database management systems three level of ANSI SPARC architecture life teacher and student ,company and employee or for NGO etc.

Illustrate the diagram - association as a cache, Association as a cache ...

Association as a cache This association must be updated when any new element is added to it, but testing for overlap using association is more efficient.    Figure:

Explain instance and schemas, Explain Instance and schemas? Instances ...

Explain Instance and schemas? Instances and schemas: Databases changes over time as the information is deleted and inserted. The collection of information stored in database

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