Single valued normalisation, Database Management System

Assignment Help:

Single Valued Normalisation

 Codd in the year 1972 formed three normal forms (1NF, 2NF, and 3NF). These were based on functional dependencies between the attributes of a relation. Later Codd and Boyce proposed another normal form known as the Boyce-Codd normal form (BCNF). The fourth and fifth normal forms are based on multivalue and join dependencies and were proposed soon.  In this part we will do normal forms till BCNF only. Fourth and fifth normal forms are afar the scope of this course. For all practical purposes, BCNF or the3NF are quite adequate since they remove the anomalies talk about for most common situations. It should be obviously understood that there is no obligation to normalise relations to the maximum possible level. Performance should be engaged into account and sometimes an organisation may take a decision not to normalise, say, beyond third normal form. But, it should be noted that such designs should be careful sufficient to take care of anomalies that would result as of the decision above.

Intuitively, the second and third normal forms are planned to result in relations such that each relation have information about only one thing (either an relationship or a entity). A sound E-R model of the database would make sure that all relations either give facts about an entity or about a relationship resulting in the relations that are get being in 2NF or 3NF.

Normalisation results in decomposition of the original relation. It should be noted that decomposition of relation has to be always rely on principles, such as functional dependence, that ensure that the original relation may be reconstructed from the decomposed relations if and when needed. Careless decomposition of a relation can result in loss of information. We will talk about this in detail in the later section. Let us now describe these normal forms in more detail.

 


Related Discussions:- Single valued normalisation

Discuss how the bi-directional implementations are made, Discuss how the bi...

Discuss how the bi-directional Implementations are made. In bi-directional implementation of the association, a pair of references must implement every link. The declarations a

Objectives-database recovery and security, Objectives Define the te...

Objectives Define the terms RECOVERY and INTEGRITY; Define Recovery Techniques; Explain Error and Error detection techniques, and Define types of Authorisation.

What is multivalued attribute, What is Multivalued Attribute? Multival...

What is Multivalued Attribute? Multivalued Attribute - Multivalued attribute might have more than one value for an entity. For instance, PreviousDegrees of a STUDENT.

Explain interblock gap, Explain Interblock gap? Interblock Gap - A trac...

Explain Interblock gap? Interblock Gap - A track of a disk is separated into equal-sized disk blocks. Blocks are separated through fixed-size gaps, called as interblock gaps th

Hierarchical data representation model, Examples:- Hierarchical Model: I...

Examples:- Hierarchical Model: It tells data as and relationships by hierarchy of data values. Figure illustrates an example of hierarchical model. Now a day's these models are

Explain the fundamental concepts of object-orientation, Explain the Fundame...

Explain the Fundamental concepts of object-orientation Software developers, data base administrators (DBAs) need to be familiar with fundamental concepts of object-orientation.

Column constraints, Column Constraints: NOT NULL, UNIQUE, CHECK, PRIMARY K...

Column Constraints: NOT NULL, UNIQUE, CHECK, PRIMARY KEY, DEFAULT, REFERENCES, On  delete  Cascade :  Using  this  key  whenever  a  parent  row  is  removed  in  a referenced

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