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

Define hash files organization, Define Hash files organization a. Hashi...

Define Hash files organization a. Hashing includes computing the address of a data item by calculating a function on the search key value.   b. A hash function h is a functi

Define transitive dependencies, What do you understand by transitive depend...

What do you understand by transitive dependencies? Define with an example any two problems that can take place in the database if transitive dependencies are available in the datab

Project on designing and creating a database , This project will involve de...

This project will involve designing and creating a database for an organization.  In the design of a database, there is no single "perfect" design.  So your database design may not

2phase locking, we need example of 2phase locking

we need example of 2phase locking

Query evolution, what is query processing ,query optimization and performan...

what is query processing ,query optimization and performance turring?

Why were functional methods fashionable in early days, Why were functional ...

Why were functional methods fashionable in early days? These are inspired directly by computer architecture and thus popular among computer scientist in early days. The divisio

E-R MODEL, WHAT IS MEANT BY E-R MODEL

WHAT IS MEANT BY E-R MODEL

Basic set operation, These are the binary operations; i.e., each is applied...

These are the binary operations; i.e., each is applied to two relations or sets. These two relations can be union compatible excluding in case of Cartesian product. Two relations R

Data management, Develop a database broker framework to implement a persist...

Develop a database broker framework to implement a persistence mechanism for the domain objects involved in the use case dealt with in Question 2.  a. Specify the attribute type

Prepare entity relationship diagram for models your design, This project re...

This project requires you to perform a systems analysis and then design a system solution using database software. Ace Auto Dealers specializes in selling new vehicles from Subaru.

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