Explain projection operation distribute over union operation, Database Management System

Assignment Help:

Illustrate the statement 'Projection operation distributes over the union operation'. Give an example.

Ans: Π_L(E₁ ∪ E₂) = (Π_L(E₁)) ∪ (Π_L(E₂))

This says that result acquired by projecting on an attribute set A, after taking union of two relations is similar as union of two relations each of which is a projection of original relations on A.

Related Discussions:- Explain projection operation distribute over union operation

Operator precedence-data manipulation language, Operator Precedence The...

Operator Precedence The basic operators used in SQL are * / - + Operators of the similar priority are evaluated From Left to right Parentheses are used to force priorit

Create database for car application, The Database MySQL scripts cars_f...

The Database MySQL scripts cars_for_sale.sql and car_details.sql containing the data to use for this task have been supplied. To complete this task, you need to first create

Demonstrate the uml model, Demonstrate the UML model Using UML, it is p...

Demonstrate the UML model Using UML, it is possible to generate code in any of the programming language from UML model (called forward engineering) and rebuild a model from an

Differentiate between primary and secondary storage, Differentiate between ...

Differentiate between Primary and secondary storage? Primary and secondary storage - Primary storage device stores the data temporarily. Primary storage is commonly used thro

State the process of inheritance adjustment, Inheritance Adjustment As...

Inheritance Adjustment As in object oriented analysis and design terms inheritance defines a relationship between classes, where as one class shares structure or behaviour def

Benefits of using a relational database management system, Question 1: ...

Question 1: a) What is the difference between a non-impact and impact printer? b) Which type of printer is generally used in a supermarket to print your receipt? Describe

Why we use delegation to share implementation, Use Delegation to Share Impl...

Use Delegation to Share Implementation The delegation " Delegation comprises of catching an operation on one object and sending it to other object which is part, or related to

Horizontal Fragmentation, I want to fragment existing table using java code...

I want to fragment existing table using java code... help me..!!

Back up files, what is the importance of back up files

what is the importance of back up files

Primary index, Primary index A primary index is a file that has a sorte...

Primary index A primary index is a file that has a sorted series of records having two columns: a block address for that key field in the data file; and the ordering key field.

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages