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 what is ddl, Explain what is DDL? DDL - Data Definition Languag...

Explain what is DDL? DDL - Data Definition Language: statements used to define the database structure or schema. Some examples: CREATE - to create objects in the database ALT

Compare the efficiency of the two mining processes, Consider the following ...

Consider the following database containing five transactions. Let min_sup = 60%. Mine all frequent itemsets using Apriori and FP-growth algorithm. Compare the efficiency of the t

Write short note on data models, Write short note on Data models? Data...

Write short note on Data models? Data models: A data model is an abstract model which elaborates how data is represented and accessed. The term data model has two commonly ac

Data modelling and normalization methodology, MOSS VALE is a town with 1500...

MOSS VALE is a town with 15000 inhabitants. The fire department wishes to develop a system that automates the despatch of fire engines to attend fires. The ERD below describes the

Whta is the advantage of the database management approach, Whta is the adva...

Whta is the advantage of the database management approach? The advantage of the database management approach is data is integrated and can be accessed by multiple programs.

C PROBLEMS, how to solve the C type problems?

how to solve the C type problems?

Describe the grant function and explain security, Describe the GRANT functi...

Describe the GRANT function and explain, how it associates to security. What kind of privileges may be granted? How are they revoked? Ans: Since more than one user can aacce

Explain about database system structure, Explain about database system stru...

Explain about database system structure? Storage manager Authorization and integrity manager Transaction manager File manager Buffer manager Storage manager

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