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: ΠL(E1 ∪ E2) = (ΠL(E1)) ∪ (ΠL(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

Describe physical data independence, Describe Physical Data independence ? ...

Describe Physical Data independence ? Physical Data Independence - It is capacity to modify the internal schema without having to change conceptual schema. Therefore, the exter

What is difference among mysql_connect and mysql_pconnect, What is differen...

What is difference among mysql_connect and mysql_pconnect? Mysql_connect() opens a new connection to the database while mysql_pconnect() opens persistent connection to the data

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

Distributed query and transaction processing, Distributed query and transac...

Distributed query and transaction processing a.  Construct a query around any one of the functional divisions you made in 4a such that if executed in the distributed design of 4

Object-based models - data models, Object-based Models: Use objects as key ...

Object-based Models: Use objects as key data representation components . Examples:-   Entity-Relationship Model: It is a collection of real world objects known as entitie

Data redundancy, Data Redundancy -A lot of information is being repeated in...

Data Redundancy -A lot of information is being repeated in the relation. For instance, the information that MCS-014 is named SSAD is repetitive, address of Rahul is "D- 27, Main ro

How we can implement relationships when designing tables, You want to imple...

You want to implement following relationships when designing tables. How would you do it? a.) One-to-one b.) One-to-many c.) Many-to-many a.) One-to-One relationship -

Information infrasture, what benefit can a company gain by managing its own...

what benefit can a company gain by managing its own infrasture and services

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