Project operation, Database Management System

Assignment Help:

The PROJECT operation

The project operation is used to choose the records with specified attributes as discarding the others based on some related criteria. This is denotes as ∏

1913_relation.png

(Relation) Example:

Consider the relation PERSON. If you want to display only the names of persons then the project operation will be used as follows:

Π Name (PERSON)

The resultant relation will be as follows:

NAME

Sanjay Prasad

Sharad Gupta

Vibhu Datt

Note: -

1) Π ( Π (R))= Π (R)

As long as have attributes in .


Related Discussions:- Project operation

Characteristics, what are the main characteristics of database

what are the main characteristics of database

Why are cursors necessary in embedded sql, Why are cursors necessary in emb...

Why are cursors necessary in embedded SQL? A cursor is an object used to store the output of a query for row-by-row processing through the application programs. SQL statements

Post vbulletin hack and new server problem, Project Description: My VBul...

Project Description: My VBulletin forum was hacked, and soon after my server machine died. So, I'm now on a new machine, and I think that I've taken care of 99% of the hacking..

How relational calculus is different from relational algebra, How Relationa...

How Relational Calculus is different from Relational Algebra? What do understand by TRC queries and DRC queries?  Ans: Relational calculus contain two calculi, the tuple relati

What are the object-oriented approaches, What are the object-oriented appro...

What are the object-oriented approaches Software systems which are designed with structured design methodology never support some of desired quality attributes for example reus

Define first normal form and second normal form, First Normal Form and seco...

First Normal Form and second normal form First Normal Form (1NF) A relation is said to be in 1NF if it having no non-atomic values and each row can give a unique combinat

MANAGEMWNT OF PRINCILES AND TECHNIQUES., HOW TO SOLVE THE LP Problems by si...

HOW TO SOLVE THE LP Problems by simplex method?z=x1+-3x2+2x3

What are the four main characteristics of the database, What are the four m...

What are the four main characteristics of the database approach? The four major characteristics of the database approach are: 1. Self-describing nature of a database system. 2.

External failure-database recovery and security, External failure : A failu...

External failure : A failure can also result because of an external cause, such as earthquakes, fire, floods, etc. The database must be duly backed up to avoid troubles occurring d

What is disadvantages of dbms, What is Disadvantages Of DBMS ? 1. Cos...

What is Disadvantages Of DBMS ? 1. Cost of Software and Hardware and Migration - A important disadvantage of the DBMS system is cost. 2. Reduced Response and Throughpu

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