Division operation, Database Management System

Assignment Help:

To do the division operation R1 ÷ R2, R2 should be a correct subset of R1. In the following example R1 have attributes A and B and R2 have only attribute B so R2 is a correct subset of R1. If we perform R1 ÷ R2 than the resultant relation will have those values of A from R1 that are related to all values of B present in R2.

Example

A

B

A1

B1

A1

B2

A2

B1

A3

B1

A4

B2

A5

B1

A3

B2

Let R1

If R2                    R3= R1 ÷ R2                      If R2                       R3= R1 ÷ R2

180_DIVISION operation.png

If R2                  R3= R1 ÷ R2                                               If R2             R3= R1 ÷ R2

1567_DIVISION operation1.png

Figure:  The Division Operation

Note:

               Degree of relation: Degree (R ÷ S)=Degree of R - Degree of S.


Related Discussions:- Division operation

Explain the disadvantages of a file processing system, Explain the disadvan...

Explain the disadvantages of a file processing system? Ans: Disadvantages of File Processing Systems include: 1) Data Redundancy 2) Data Inconsistency 3) Difficult to acce

Describe the terms ‘database'' and ‘data warehouse'', Problem: ‘Users a...

Problem: ‘Users and Information system specialists need to spend inordinate amounts of time locating and gathering data' (Watson and Hal, 1998) Recent developments in the ar

Transaction, what are the states of transaction?

what are the states of transaction?

Oracle RDBMS, compare the features of oracle RDBMS with MySQL and Microsoft...

compare the features of oracle RDBMS with MySQL and Microsoft SQL server

Define object-oriented database, Question : Object-Oriented Database (O...

Question : Object-Oriented Database (OODM) is defined as a logical data model that captures the semantics of objects supported in object-oriented programming. An Object-Oriente

Describe the host language, Describe the host language? Host Language:...

Describe the host language? Host Language: You could write applications along with SQL statements embedded inside a host language. The SQL statements give the database inter

Key, Q.   Explain the terms key constraints participation constraints and m...

Q.   Explain the terms key constraints participation constraints and mapping caradinalities in ER model.  Participation Constraints :   The participation of an entity set E i

Assignment topic, assume we have the following apllicationthat model sccer ...

assume we have the following apllicationthat model sccer team the games they play and the players inv each teamin the design we want to capture

What is the use of raid, What is the use of RAID? A variety of disk-org...

What is the use of RAID? A variety of disk-organization methods, collectively called redundant arrays of independent disks are used to better the performance and reliability.

How many types of users works on database, How many types of users works on...

How many types of users works on database? Users are differentiated through the way they expect to interact along with the system (i) Application programmers-interact with

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