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

What are the different kinds of database end users, What are the different ...

What are the different kinds of database end users? Discuss the major activities of each? End-Users - End-users are the people whose jobs need access to the database for que

Evaluate the null hypothesis, 1.Suppose you are given a dataset that consis...

1.Suppose you are given a dataset that consists of a random sample of tasters, on which the following variables were obtained: (y) Zpref = taste preference for green beans store

Update operations, The Update Operations : Update operations are used fo...

The Update Operations : Update operations are used for altering database values. The constraint violations faced by this operation are logically the similar as the problem faced

Data models, After going by the database architecture, let us now dwell on ...

After going by the database architecture, let us now dwell on an important query: how is the data organised in a database? There are a lot of basic structures that exist in a datab

Define about the stored procedure, Define about the Stored Procedure - ...

Define about the Stored Procedure - It's a set of T-SQL statements combined together to perform a single task formed by combining numerous small tasks. - When you essentiall

What are the two types of errors, What are the two types of errors? The...

What are the two types of errors? The two types of errors are: a) Logical error b) System error

Write short notes on domain relational calculus, Write short notes on domai...

Write short notes on domain relational calculus The domain relational calculus uses domain variables that take on values from an attribute domain rather than values for whole t

List some security violations, List some security violations (or) name any ...

List some security violations (or) name any forms of malicious access. A) Unauthorized reading of data B) Unauthorized modification of data C) Unauthorized destruction of

What are the two methods for dealing deadlock problem, What are the two met...

What are the two methods for dealing deadlock problem? The two procedures for dealing deadlock problem is deadlock detection and deadlock recovery.

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