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

Extended star schema, Northwind Pty Ltd sells a variety of food products th...

Northwind Pty Ltd sells a variety of food products throughout the world.  They want to use the reporting features of SAP's Business Information Warehouse to better understand their

Guidelines for creation of table, Guidelines for creation of table: ...

Guidelines for creation of table: Table name should begin with an alphabet. In table name, single quotes and blank spaces are not allowed. Reserve words of that DBM

What is data defination language, What is DDL? Make a list of commands with...

What is DDL? Make a list of commands with short description used in DDL Ans: Data Definition Language that is abbreviated as DDL is a computer language for defining data struct

Data warehouse, #queDefine a job scheduling strategy that will meet busines...

#queDefine a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pic

Relation schema for student, Example RELATION SCHEMA for STUDENT: STU...

Example RELATION SCHEMA for STUDENT: STUDENT (Roll No: string, name: string, login: string, age: integer) RELATION INSTANCE

What is storage manager, What is storage manager?  A  storage  manager ...

What is storage manager?  A  storage  manager  is  a  program  module  that  gives  the  interface  between the Low level data  kept in a database and the application programs

Update operations, The Update Operations : Update operations are used fo...

The Update Operations : Update operations are used for altering database values. The constraint violations faced by this operation are logically the similar as the problem faced

Draw enhanced er-diagram for hierarchy of a student database, Draw an EER d...

Draw an EER diagram that captures the "is-a" hierarchy of students in another simple database. The database captures both the "basic" information (say, student ID and student name)

What are the object-oriented approaches, What are the object-oriented appro...

What are the object-oriented approaches Software systems which are designed with structured design methodology never support some of desired quality attributes for example reus

Define instance and schema, Define instance and schema?  Instance:  C...

Define instance and schema?  Instance:  Collection of  data  kept in the  data  base  at  a  particular  moment  is  known as an Instance of the database.  Schema: The o

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