Eliminate redundant data, Database Management System

Assignment Help:

 Eliminate Redundant Data

In the "Database Relation" above, the primary key is made up of the D-ID and the Emp-ID. The database-name relies only on the D-ID. The similar database-name will appear redundantly every time its associated D-ID appears in the Database Relation. The database relation has redundancy, for example D-ID value 4 is oracle is repetitive twice. In addition, it also experiences insertion anomaly that is we cannot enter Sybase in the relation as no employee has that skill.

The deletion anomaly also exists. For instance, if we remove employee with Emp-ID 3; no employee with FoxPro knowledge lefts and the information that D-ID 3 is the code of FoxPro will be gone.

To avoid these troubles, we require second normal form. To achieve this, we isolate the attributes depending on both parts of the key from those depending only on the D- ID. This result in two relations: "Database" which gives the name for every D-ID,

and "Emp-database" which lists the databases for each employee. The employee relation is already in 2NF as all the EMP-ID determines all different attributes

Employee Relation

 Emp-ID

Emp-Name

1

Gurpreet Malhotra

2

Faisal Khan

3

Manisha Kukreja

4

Sameer Singh

 

Emp-database

Relation

Emp-ID

D-ID

2

1

4

2

3

3

1

4

4

4

 

 

 

 

Database Relation

D-ID

Database

1

Access

2

DB2

3

FoxPro

4

Oracle


Related Discussions:- Eliminate redundant data

How to insert data in your table from another table, How to Insert data in ...

How to Insert data in your table from another table? insert into e.g, To insert tuples from employee into N_emp created above, use following statement Insert into N_emp

What are the advantages of relational data model, What are the advantages o...

What are the advantages of relational data model? Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer

Write expressions in relational algebra, Given the subsequent relations: ...

Given the subsequent relations:    vehicle (reg_no, make, colour)    Person (eno, name, address)    Owner (eno, reg_no)   Write expressions

Explain the functions of data manager, Explain the functions of data manage...

Explain the functions of data manager? Functions of Data Manager : - Convert operations in user's queries coming directly through query processor or indirectly in an applicatio

Illustrate the class diagram for class room scheduling, Illustrate the clas...

Illustrate the class diagram for class room scheduling system If in any college, the number of classrooms are limited which have to be allocated to various classes and instruct

Discuss the types of integrity constraints with example, Discuss the types ...

Discuss the types of integrity constraints in which must be checked for the update operations - Insert and Delete. Give examples. Insert operation can violet any of the subse

Find a 3nf decomposition , Find a 3NF decomposition of the following relati...

Find a 3NF decomposition of the following relation scheme: University (Faculty, Dean, Department, Chair, Professor, Rank, Student}. The University relation satisfies the following

What is multilevel index, Multilevel Index The Multilevel Index is a m...

Multilevel Index The Multilevel Index is a modification of the secondary level index system. In this system we might be use even more number of levels in case the table is eve

Cluster analysis project, (a) Data Mining Process : In the context of t...

(a) Data Mining Process : In the context of this cluster analysis project , and in your own words , explain how you would execute the first stage of data mining, namely the "P

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