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

Enforce referential integrity, Use Access 2007 to create a database calle...

Use Access 2007 to create a database called UniLib.mdb. - this file should be created on your personal drive at the university (or C: if you're using Access 2007 at home) and t

Why does a dbms query language is designed, Why does a DBMS query language ...

Why does a DBMS query language is designed? A DBMS query language is designed to support end users who use English-like commands. support in the development of complex applicat

Datawarehouse, 1) Define a job scheduling strategy that will meet business ...

1) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pict

Objectives-database recovery and security, Objectives Define the te...

Objectives Define the terms RECOVERY and INTEGRITY; Define Recovery Techniques; Explain Error and Error detection techniques, and Define types of Authorisation.

Transaction, .#question. Discuss the problem which may arise during concurr...

.#question. Discuss the problem which may arise during concurrency control and recovery in distributed database which are not encountered in controlized database environment.

What is data block, What is data block? Data Block - In oracle the data...

What is data block? Data Block - In oracle the data blocks are referred to as tablespaces. A tablespace is an fields of disk consisting of one or more disk files. A tablespace

What are metrics for choosing the best algorithm, What are metrics for choo...

What are metrics for choosing the best algorithm? Matrices for choosing the best algorithms are as below: Computational complexity Ease of understand ability and im

Explain dbms- ddl-domain-alias, Briefly explain each of the following datab...

Briefly explain each of the following database terms. Use no more than 2-3 lines for each term. 1. DBMS 2. Update Anomaly 3. Alias (referring to tables in SQL queries)

What is called block-level striping, What is called block-level striping? ...

What is called block-level striping? Block level striping stripes blocks across many disks. It treats the array of disks as a large disk, and provides blocks logical numbers

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