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 how the binary tree, QUESTION (a) Give two advantages of using ...

QUESTION (a) Give two advantages of using Linked List as compared to arrays. (b) (i) You are working as programmer at the Orange Mauritius branch. You have been asked to cre

Confirming.., I just purchased a document for you guys and wanted to confir...

I just purchased a document for you guys and wanted to confirm that it will be send within an hour or 2 to my email or where will document be sent to?

What is a cascading update, What is a cascading update? Referential int...

What is a cascading update? Referential integrity constraints needs that foreign key values in one table correspond to primary key values in another. If the value of the primar

Differentiate between static hashing and dynamic hashing, Differentiate bet...

Differentiate between static hashing and dynamic hashing.  Ans: Static Hashing comprises the number of primary pages in the directory fixed. So, while a bucket is full, we requ

Super keys, A super key is an attribute or set of attributes used to recogn...

A super key is an attribute or set of attributes used to recognize the records uniquely in a relation. For instance, in the Relation PERSON defines earlier PERSON_ID is a super

Implementing a distributed database system, A distributed database is defin...

A distributed database is defined as "a collection of multiple logically interrelated database which are physically distributed over a computer network" (a) Give any three advan

What are wait-for-graphs, What are wait-for-graphs?Give the algorithm to co...

What are wait-for-graphs?Give the algorithm to construct a wait-for-graph from a given schedule of transactions? How can deadlocks be detected from wait-for-graphs?   Ans:  The

What are the basic objects of the data dictionary, What are the basic objec...

What are the basic objects of the data dictionary? Tables Domains Data elements Structures Foreign Keys

Support by adding indexes, Support by Adding Indexes Multiple indexes c...

Support by Adding Indexes Multiple indexes can be used to access a data file by multiple access paths. In such a scheme only single copy of the data is consider, only the numbe

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