Let us now talk about the relational operations:

SELECT

The select operation is used to select few specific record from the database based on different criteria, This is a unary operation mathematically denoted as σ

Syntax:

σ  (Relation)

The Boolean expression is specified in is made of a number of clauses of the form:

or

Comparison operators in the set { ≤, ≥, ≠, =, <, <} apply to the attributes whose domains are ordered value like as integer.

---

Related Discussions:- Relational operations

What is oracle process explain for processes of oracle, What is Oracle Proc... What is Oracle Process? Explain any four processes started by Oracle. Oracle Process is as follows: SMON: The System Monitor carries out a crash recovery while a crashed in

Define 3nf normal form, 3NF Normal Form A relation schema R is in 3NF ... 3NF Normal Form A relation schema R is in 3NF if it is in 2NF and for each FD X A either of the following is true X is a Super-key of R. A is a prime attribute of R

What is catalog in dbms, What is catalog in DBMS? Catalog - A relationa... What is catalog in DBMS? Catalog - A relational DBMS maintains information about every table and index in which it contains. A catalog is a collection of special tables that st

To delete a particular column in a relation which command, To delete a part... To delete a particular column in a relation which command is used ? To delete a particular column in a relation ALTER command is used.

Why object-oriented system use the relational dbms, Why, generally does an ... Why, generally does an object-oriented system use the relational DBMS? The reasons for using relational DBMS for OO systems could be any combination of following: a. Many or

Employees and projects scenario, how many hourse have been spent on a certa... how many hourse have been spent on a certain project

What is difference between truncate and delete, What is difference between ... What is difference between TRUNCATE and DELETE? - Truncate can't be rolled back whereas Delete can be. - Truncate keeps the lock on table whereas Delete keeps the lock on ea

ERD, The entity type STUDENT has the following attributes: Student Name, Ad... The entity type STUDENT has the following attributes: Student Name, Address, Phone, Age, Activity, and No of Years. Activity represents some campus-based student activity, and No o

Using sql create a view rs for the relations r and s, Using SQL create a vi... Using SQL create a view RS for the relations R and S. The view consists of the columns A and D renamed as X and Y in that order. Insert a tuple into it. Show the contents of t

Related Rates, All edges of a cube are expanding at a rate of 6 centimeters... All edges of a cube are expanding at a rate of 6 centimeters per second. How fast is the surface area changing when each edge is (a) 2 centimeters and (b) 10 centimeters?

Write Your Message!

Name