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

Er-diagram, courier company er-diagram

courier company er-diagram

Data mining objective, State your technical objectives for mining the data....

State your technical objectives for mining the data. Data Understanding. Describe the data For each attribute, give its description and data type. For numeric attributes

Clinic, Need a sample of a clinic database relationships

Need a sample of a clinic database relationships

Define instance and schema, Define instance and schema? Instance: Colle...

Define instance and schema? Instance: Collection of data stored in the data base at a certain moment is Schema: The overall design of the data base is known as the data base

Define views in relational algebra, Views in relational algebra:   1. B...

Views in relational algebra:   1. Basic expression contains either  a) A relation in the database. b) A constant relation. 2.  General expressions are madde out of sma

Explain trigger, Explain trigger? Trigger: A database trigger is proc...

Explain trigger? Trigger: A database trigger is procedural code which is automatically executed within response to certain events on a particular table in a database. Trigger

What is a query tree, What is a query tree?     Ans:  A query tree, as ...

What is a query tree?     Ans:  A query tree, as well known as operator graph, is a tree data structure that corresponds to a relational algebra expression. It denotes the inpu

Describe the objective of structural diagrams, Describe the objective of St...

Describe the objective of Structural Diagrams The main objective of structural diagram is to visualize, construct, specify and document static aspects of a system. Their eleme

Selective replication-data replication, Selective replication: This is a c...

Selective replication: This is a combination of generating small fragments of relation and replicating them rather than a entire relation. The data should be fragmented on require

Explain concurrency control, Explain concurrency control? Concurrency ...

Explain concurrency control? Concurrency control Oracles multiversion concurrency control varies from the concurrency mechanism used by some other data base vendors. Read

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