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

Create a database for their customers, The ABC Bank authority now wants to ...

The ABC Bank authority now wants to create a database for their customers. So you are requested to modify your program of Assignment A3 as follows. The main program first displa

DBMS, give some example real life situation where DBMS are most suitable

give some example real life situation where DBMS are most suitable

How to apply the bcnf decomposition , Consider the following relational sch...

Consider the following relational scheme: R (a,b,c,d,e,f) and its corresponding set of FDs {d→ a, be → c, ac → e, b → f, f → d, a → c}. a. Is the following decomposition i) non

Oracle, I have 10+ yrs exp in oracle Sql ,Pl/SQl,Forms ,Reports. I am exper...

I have 10+ yrs exp in oracle Sql ,Pl/SQl,Forms ,Reports. I am expert in assignements & Online tutoring so i want to join you. Please guide me. Thanks Brajesh Shukla +91 9899641535

Explain the relational completeness, Explain the Relational Completeness ...

Explain the Relational Completeness Codd described the term relational completeness to consider to a language that is complete with respect to first-order predicate calculus ex

Explain the role of a database administrator, Explain the Role of a databas...

Explain the Role of a database administrator a. Defining the Schema   The DBA describes the schema which consists of the structure of the data in the application. The DBA

Explain the timestamp ordering protocol, Timestamp Ordering Protocol A ...

Timestamp Ordering Protocol A timestamp is a tag that can be attached to any transaction or any data item, which indicates a specific time on which the transaction or data item

Cartesian product, If R1 and R2 are two relations or functions, then the re...

If R1 and R2 are two relations or functions, then the result of R3 = R1 × R2 is the combination of tuples that are in R1 and R2. The product is associative and commutative. Degr

List the table modification commands in sql, List the table modification co...

List the table modification commands in SQL? A) Deletion B) Updates C) Insertion D) Update of a view

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