Define the five basic operators of relational algebra, Database Management System

Assignment Help:

Define the five basic operators of relational algebra?

Five basic operators of relational algebra are:
1. Union (∪∪∪∪) - Selects tuples which are in either P or Q or in both of them. The duplicate tuples are eliminated.
R = P ∪ Q
2. Minus (-) - Removes generally common tuples from the first relation.
R = P - Q
3. Cartesian Product or Cross Product (××××) - The cartesian product of two relations is the concatenation of tuples belonging to the two relations and consisting of all probable combination of the tuples.
R = P × Q
4. Projection (ππππ) - The projection of a relation is described as a projection of all its tuples over a few set of attributes, i.e., it yields a vertical subset of the relation. It is used to either decrease the number of attributes (degree) in the resultant relation or to reorder attributes. The projection of a relation T on the attribute A is denoted through πA(T).
5. Selection (σσσσ) - Selects only some of the tuples, those satisfy given criteria, from the relation. It yields a horizontal subset of a given relation, i.e., the action is defined over a complete set of attribute names but just a subset of the tuples are involved in the result.
R = σB(P)

 


Related Discussions:- Define the five basic operators of relational algebra

Using relational algebra which query finds customers, Using Relational Alge...

Using Relational Algebra which query finds customers, who have a balance of over 1000 ? Using Relational Algebra Π Customer_name( σ balance >1000(Deposit)) is query to find cu

Determine the advanced modeling concepts, Determine the Advanced modeling c...

Determine the Advanced modeling concepts You have to follow some steps for object-oriented design. These steps for OO Design methodology are as follow:  1)  Produce objec

Mixed fragmentation, Mixed fragmentation: Sometimes, horizontal fragmentati...

Mixed fragmentation: Sometimes, horizontal fragmentation or vertical fragmentation of a database schema by itself is insufficient to sufficiently distribute the data for some appli

Database for online assignment system, i want to database for online assign...

i want to database for online assignment submission system

List the string operations supported by sql, List the string operations sup...

List the string operations supported by SQL? 1) Pattern matching Operation 2) Concatenation 3) Extracting character strings 4) Converting among uppercase and lower cas

Generalization and specialization, design a generalization specialization h...

design a generalization specialization hierarchy for a motor vehicle sales company. the company sells motorcycles, passenger cars, vens and buses.

What is omr, What is OMR? OMR (Optical Mark Recognition) is the transla...

What is OMR? OMR (Optical Mark Recognition) is the translation of marks - or the absence of marks - but not the shape of the mark on forms that have small circles ("also called

Create the database in oracle using ddl, The Assessment page has a link to ...

The Assessment page has a link to download a conceptual model, and a list of data. You are to map this conceptual model, and create the database in Oracle using your own DDL.  T

Explain the attribute inheritance, Explain the Attribute inheritance An...

Explain the Attribute inheritance Ans: Throughout the rendering of the objects in a view, attribute sets of objects higher in the view hierarchy are inherited via objects below

E-r model uses this symbol to represent weak entity set, E-R model uses thi...

E-R model uses this symbol to represent weak entity set ? A Doubly outlined rectangle symbol is used to represent weak entity set.

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