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

What is called a query -execution engine, What is called a query -execution...

What is called a query -execution engine? The query implementation engine takes a query evaluation plan, implements that plan, and returns the answers to the query.

Mention the various user privileges, Mention the various user privileges ...

Mention the various user privileges All privileges directly granted to the user or role. All privileges granted to roles that have been granted to the user or role.

State the technique for converting a state diagram to code, Q. State the Te...

Q. State the Technique for converting a state diagram to code. i) Identify the major control path. Starting with first state, find the path from diagram that corresponds

Create a database of a motor bike racing club, You have a friend that runs ...

You have a friend that runs a motor bike club that holds racing events at various venues on weekends, on a monthly basis. Some venues are private race tracks and some are dirt trac

What are the disadvantages of relational approach, What are the disadvantag...

What are the disadvantages of relational approach? Disadvantages of relational approach: • Substantial hardware and system software overhead • May not fit all business models •

Primary key, The primary key is selected from the

The primary key is selected from the

Synonyms, Synonyms It allows short names or alternative names for objects....

Synonyms It allows short names or alternative names for objects. Example :               CREATE SYNONYM D30               FOR EMPD30;   Now if we give command:

Define the third normal form, Define the Third Normal Form: The third ...

Define the Third Normal Form: The third normal form (3NF) is a normal form employed in database normalization. 3NF was initially defined by E.F. Codd in 1971. Codd's definitio

Database ass1, #quCreate a database design specification (Enhanced Entity R...

#quCreate a database design specification (Enhanced Entity Relationship Diagram (EERD) and Relational Data Model (RDM)) from the given business description. The RDM must be in 3rd

Managing database, 10A.53 Code an Oracle Database trigger to enforce the ...

10A.53 Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department. 10A.54 Code an Oracle Database trigger to allow the

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