Join operation, Database Management System

Assignment Help:

The JOIN operation is applied on two relations. When we want to choose related tuples from two given relation join is used. The join operation need that both the joined relations must have at least single domain compatible attributes.

Syntax:

R1 R2 is used to join related tuples from two relations R1 and R2 into a single tuple.

is of the form:

ANDAND..............AND.

  • Degree of Relation:

Degree (R1   R2) <= Degree (R1) + Degree (R2).

  • There are three types of joins:

a)   Theta join

When every condition is of the form A θ B, A is an attribute of R1 and B is an attribute of R2 and have the similar domain, and θ is one of the comparison operators { ≤, ≥, ≠, =, <, <}.


Related Discussions:- Join operation

What is dml compiler, What is DML compiler? DML Compiler: Translates DM...

What is DML compiler? DML Compiler: Translates DML statements in a query language within low level instructions understandable through the query evaluation engine. Attempts to

Client dbms, i need to submit in this topic.

i need to submit in this topic.

Sorting field groups we cannot use more than one key field, While sorting f...

While sorting field groups we cannot use more than one key field False.

Define the concept of object diagram, Define the concept of Object Diagram ...

Define the concept of Object Diagram An object diagram shows a set of the objects and their relationships with each other at a point of time. In a static view, object diagram

Differentiate between key and superkey, Differentiate between Key and super...

Differentiate between Key and superkey? Key and superkey - A key a single attribute or a combination of two or more attributes of an entity set in which is used to identify o

Advantages of Observation Methods, Advantages of Observation  Methods: ...

Advantages of Observation  Methods: Bailey has pointed  out four  advantages of observation: 1. Superior in Data  Collection  on Non Verbal Behavior: When  a person  a opi

How nulls are treated in comparison operator, How nulls are treated in comp...

How nulls are treated in comparison operator? Along with comparison (relational) operators, the null values are ignored as we cannot derive the relation along with the given op

Develop network database ipad app, I want an iPad app that is a simple 1 pa...

I want an iPad app that is a simple 1 page form to complete with text. The Objective is to allow a few dozen people of the same organization (they're all on iPad) to open the app,

Increases efficiency-data fragmentation, Increases efficiency : Data is sto...

Increases efficiency : Data is stored close to most often used site, therefore retrieval would be faster. Also, data that is not required by local applications is not stored, there

Define integrity, (a) Explain briefly the three parts of a relational Model...

(a) Explain briefly the three parts of a relational Model. (b) Contrast the following terms with an appropriate example: (i) stored attribute v/s derived attribute (ii) en

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