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

Database Management System, please give me introduction to full data in D B...

please give me introduction to full data in D B M S in a short assignment

What is a database, What is a database? At any given time, they're sto...

What is a database? At any given time, they're storing a tremendous amount of information - inventory, in the case of Amazon, messages and interrelationships in the case of Tw

What are the three data anomalies, What are the three data anomalies that a...

What are the three data anomalies that are likely to occur as a result of data redundancy?  Can data redundancy be completely eliminated in database approach?  Why or why not? A

Aims of the design project, The aims of the project are: 1. To enable th...

The aims of the project are: 1. To enable the students to undertake the detailed design of a specific plant or process 2. The design projects includes: process selection; und

Unrepeatable reads-problems of concurrent transactions, Unrepeatable reads ...

Unrepeatable reads : Assume T7 reads X twice during its implementation. If it did not update X itself it could be very disturbing to see a dissimilar value of X in its next read. B

Define instance and schema, Define instance and schema?  Instance:  C...

Define instance and schema?  Instance:  Collection of  data  kept in the  data  base  at  a  particular  moment  is  known as an Instance of the database.  Schema: The o

Which steps must designer take to adjust inheritance, In object oriented de...

In object oriented design, which steps must designer take to adjust inheritance? To readjust inheritance following steps should be taken: i)  Rearrange and adjust the classe

Abap/4 program, It is not possible to make an ABAP/4 program, which having ...

It is not possible to make an ABAP/4 program, which having only Subroutines. False. We can make ABAP/4 program, which having only Subroutines.

Domain constraints, Domain Constraints Domain constraints are primarily...

Domain Constraints Domain constraints are primarily formed for defining the logically correct values for an attribute of a relation. The relation allows attributes of a relatio

Define two phase commit, Define Two phase commit Two phase commit: To m...

Define Two phase commit Two phase commit: To make sure atomicity, all the sites where a transaction is being executed must agree on the final outcome of the execution. The tran

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