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

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.

What is functional dependency, A Functional dependency is described by ...

A Functional dependency is described by X Y between two groups of attributes Y and X that are subsets of R specifies a constraint on the possible tuple that can make a relation

Design and implement a database system, Safe Banking is a Canberra based cr...

Safe Banking is a Canberra based credit union, which has several branches around Canberra and Queanbeyan. YOU have taken over Safe Banking. YOU need to create a database that organ

Explain data independence, Explain data independence ? Data independenc...

Explain data independence ? Data independence is the capacity to modify the schema at one stage of a database system without having to change the schema at the further level.

Convert erd to rdm model, Regional Gardens has many nurseries, including Wa...

Regional Gardens has many nurseries, including Wagga Wagga, Bathurst, Albury, Orange, and Dubbo. Each nursery is known by its campus code, eg WW, B, A, O and D respectively. Additi

BOGUS VS GENUINE EMPOWERMENT, what is bogus empowerment. And what is genuin...

what is bogus empowerment. And what is genuine empowerment

Why is database redesign necessary, Why is database redesign necessary? ...

Why is database redesign necessary? Database redesign is essential for two reasons. First, redesign is essential both to fix mistakes made during the initial database design. S

Explain candidate key and super key, Explain Candidate Key and Super Key ...

Explain Candidate Key and Super Key A super key is a set of one or more than attributes that, taken collectively, permits us to identify uniquely a tuple in the relation. Wher

What is a candidate key, What is a candidate key? Minimal super keys ar...

What is a candidate key? Minimal super keys are known as candidate keys.

Management information system, Explain the challenges before an E-business ...

Explain the challenges before an E-business management.

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