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

Describe the algorithm to draw the dependency graph, Describe the algorithm...

Describe the algorithm to draw the dependency graph?   Ans: Algorithm to draw Precedence Graph is like this: a.  For every transaction T i participating in schedule S, make

Views, what is view?explain

what is view?explain

Defining internal classes and operations, Defining Internal Classes and Ope...

Defining Internal Classes and Operations When we enlarge algorithms, new classes can be added to the store intermediate results. A complex operation could be looked at, as a c

Three levels of ANSI-SPARC architecture, a need some real life examples of...

a need some real life examples of database management systems three level of ANSI SPARC architecture life teacher and student ,company and employee or for NGO etc.

Write a query that uses the union operator, Write a Query that uses the UNI...

Write a Query that uses the UNION Operator 1. Use the Software Experts database to:   a. Display the first and the last name of all consultants who worked on any projects f

Describe the nested-loop join and block-nested loop join, Describe the nest...

Describe the nested-loop join and block-nested loop join.   Ans:   The block nested- loop join algorithm is as described below:     for every block B r of relation R do beg

Command line interfaces, Command Line Interfaces: These are interactive int...

Command Line Interfaces: These are interactive interfaces, character-based that let you use the complete power and functionality of the DBMS query language directly. They permit yo

Database application and creation, Create Relational Database Model (RDM) f...

Create Relational Database Model (RDM) for Sailing bed and breakfast club Table_Name( attribute_1, attribute_2, attribute_3, ? ,attribute_x) Primary Key ( attribute_1, attribute_2)

Define two-phase locking protocol, Define two-phase locking protocol. A...

Define two-phase locking protocol. Ans: Two-phase locking is significance in the context of ensuring that schedules are serializable. The two-phase locking protocol defines a p

Project, the of super market system done in database

the of super market system done in database

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