Unit database integrity, Database Management System

Assignment Help:

Relations create the database. They must satisfy various properties, like no duplicate tuples, no ordering of tuples, and atomic attributes, etc. Relations that satisfy these basic needs may still have some undesirable characteristics such as data redundancy, and anomalies.

What are these undesirable characteristics and how can we eliminate them from the database system? This part is an attempt to answer this question. Though, please note that most of these undesirable properties do not arise if the database modelling has been carried out very carefully using some method like the Entity-Relationship Model. It is still important to use the methods in this unit to check the database that has been acquired and ensure that no mistakes have been made in modeling.

The central thought in these discussions is the concept of Database integrity, the notion of functional dependency, which rely on understanding the semantics of the data and which deals with what information in a relation is dependent on what other information in the relation. Our prime objective in this section is to describe the concept of data integrity, functional dependence and then describes normal forms using functional dependencies and using other types of data dependencies.

OBJECTIVES

After reading this section you should be able to

  • Explain the concept of entity integrity;
  • Define relational database referential integrity constraints;
  • Explain the concept of functional dependency, and
  • show how to use the dependencies information to decompose relations; whenever essential to obtain relations that have the desirable properties that we want without losing any of the information in the original relations.

 


Related Discussions:- Unit database integrity

Data base design, how to design a bakery business in data base

how to design a bakery business in data base

What are domain constraints, What are domain constraints? A domain is a...

What are domain constraints? A domain is a set of values that might be assigned to an attribute .all values that appear in a column of a relation must be taken from the similar

Relational algebra operators, Question 1 Draw a Data Flow Diagram for a...

Question 1 Draw a Data Flow Diagram for a University scenario Question 2 Discuss the following with suitable examples Relational Algebra Operators Database Pla

ER Diagram, Hi I have got an assignment for making an er diagram for market...

Hi I have got an assignment for making an er diagram for market management software can any budy help me?

Explain the structure of well formed formulae, Explain the structure of wel...

Explain the structure of well formed formulae in relational calculus. Ans: a. An atom is a formula b. If P1 is a formula, after that so are ¬P1 and (P1) c. If P1 and P2 a

State in brief about object design, Give the Introduction of OBJECT DESIGN ...

Give the Introduction of OBJECT DESIGN Strategies which are selected during system design are carried out in object-oriented design. In this procedure, objects which are identi

Explain pipelining, Explain pipelining.        Ans: In order to describ...

Explain pipelining.        Ans: In order to describe pipelining in simple terms, think of it as breaking down processor functions into smaller and smaller parts. For instance,

Illustrate how customer relationship is promoted, FitAll Ltd is a company t...

FitAll Ltd is a company that manufactures clothes. Its processes are manual and there are stand-alone Information Systems that aid to manage them. The Information Systems were purc

What is a view in sql and when can views be updated, What is a view in SQL?...

What is a view in SQL? When can views be updated? A view is a virtual table which consists of columns from one or more tables. Through it is same to a table; it is stored in

Discuss on transmission impairments, Question 1 Discuss on transmission im...

Question 1 Discuss on transmission impairments Question 2 What is framing? Question 3 Write a note on 10Base2 10Base- T Question 4 Explain the rev

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