Eliminate columns not dependent on key, Database Management System

Assignment Help:

Eliminate Columns Not Dependent On Key

The Employee Relation satisfies -

First normal form - As it has no repeating groups.

Second normal form - As it do not have multi-attribute key.

The employee relation is in 2NF but not 3NF. So we take this table only later than adding the required attributes.

 

Employee Relation

Emp-ID

Emp-Name

Department

Department-Loc

1

Gurpreet Malhotra

A

N-Delhi

2

Faisal Khan

A

N-Delhi

3

Manisha Kukreja

B

Agra

4

Sameer Singh

C

Mumbai

The key is Emp-ID, and the Dept-Name and location defines only about Department, not an Employee. To get the third normal form, they must be moved into a individual relation. Since they define a department, therefore the attribute Department becomes the key of the new "Department" relation.

The motivation for this is the similar for the second normal form: we want not to use or avoid update, insertion and deletion anomalies.;

Department-Relation

Dept-ID

Department

Department Loc

1

A

N-Delhi

2

B

Agra

3

C

Mumbai

 

Employee-List

Emp-ID

Emp-Name

1

Gurpreet Malhotra

2

Faisal Khan

3

Manisha Kukreja

4

Sameer Singh

The rest of the Relation remains similar.

The last two steps: Isolate Semantically Related Multiple Relationships and Isolate Independent Multiple Relationships, changes the relations to higher normal form and are thus not discussed here. They are not even needed for the current example.


Related Discussions:- Eliminate columns not dependent on key

Give some encryption techniques, Give some encryption techniques? A)  D...

Give some encryption techniques? A)  DES  B) AES  C) Public key encryption

Data Minnning, Can i get help with weka software

Can i get help with weka software

Example of relational operations, Consider the relation PERSON. If you want...

Consider the relation PERSON. If you want to display details of persons having age less than or equal to 30 than the select operation will be used as follows: σ AGE The resu

A weak entity set and its identifying relationship, Q.  Define a weak entit...

Q.  Define a weak entity set and its identifying relationship. List the necessary conditions for a meaningful identifying relationship set of a weak entity set.    Entity is a t

Define about the stored procedure, Define about the Stored Procedure - ...

Define about the Stored Procedure - It's a set of T-SQL statements combined together to perform a single task formed by combining numerous small tasks. - When you essentiall

File Management Principles, What are the requirements to ensure the objecti...

What are the requirements to ensure the objectives of file management principle is realized?

Explain key benefits of a content management system, Question: (a) What...

Question: (a) What do you meant by content management and briefly describe four major components of a Content Management System? (b) Explain key benefits of a Content Manage

Demonstrate the design of associations, Demonstrate the Design of associati...

Demonstrate the Design of associations During object design phase we must design a strategy to implement associations. Association may be unidirectional or bi-directional. Wha

Assignment, Gyan Gurukul is a software company that provides software relat...

Gyan Gurukul is a software company that provides software related solution. Ashutosh Dubey who is the director of Gyan Gurukul want a three-level schema architecture for the Gyan G

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