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

Create a database schema, Consider a database schema consisting of four rel...

Consider a database schema consisting of four relations, whose schemas are: Product (maker, model, type) PC (model, speed, ram, hd, price) Laptop (model, speed, ram, hd, s

Method of analyzing association traversal, Analyzing Association Traversal ...

Analyzing Association Traversal Till now, we have supposed that associations are bi-directional. But in the case of traversal, it is in only one direction in any application,

Binary relationships, One-to-one relationship: For every 1:1 relationshi...

One-to-one relationship: For every 1:1 relationship type R in the ER diagram including two entities E1 and E2 we take one of entities (say E1) preferably with total participatio

Explain the term- event, Event Occurrence of a process is called event...

Event Occurrence of a process is called event. In other words, the object can receive many input instructions. The changes which occur due to these instructions are known as e

Relational algebraic operators, Problem Explain at least five relationa...

Problem Explain at least five relational algebraic operators with a suitable example. Note: All the above descriptions should be done by taking at least two examples from ou

Normalization, Normalize the given relation to 3NF, justifying each step

Normalize the given relation to 3NF, justifying each step

What is natural language interfaces, What is Natural Language Interfaces? ...

What is Natural Language Interfaces? Natural Language Interfaces - These interfaces accept requests written within English or a few other language and attempt to "understand" t

In an e-r diagram how attributes are represented, In an E-R diagram how att...

In an E-R diagram how attributes are represented ? In an E-R diagram attributes are represented in a ellipse.

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