Join operation, Database Management System

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 { ≤, ≥, ≠, =, <, <}.

Posted Date: 3/6/2013 5:53:13 AM | Location : United States







Related Discussions:- Join operation, Assignment Help, Ask Question on Join operation, Get Answer, Expert's Help, Join operation Discussions

Write discussion on Join operation
Your posts are moderated
Related Questions
What is a candidate key? Minimal super keys are known as candidate keys.

Relations create the database. They must satisfy various properties, like no duplicate tuples, no ordering of tuples, and atomic attributes, etc. Relations that satisfy these basic


I want Database Of United Kingdom with Criteria of:\r\n\r\n1). Name, Number, City, State, Postal Code, Address, Email id, DOB.\r\n\r\n2). Unsecure Debts only adds Credit Card Payme

Data Replication "If a relation R has its copies kept at two or more sites, then it is considered replicated". But why do we replicate a relation? There are several advan

Question A What is operational intelligence? Question B What is Business Intelligence? Explain the components of BI architecture Question C Differentiate between databas

What are the kinds of Strings?  -A binary string in MySQL is one that MySQL treats as case sensitive in comparisons. -A non binary string in MySQL is one that MySQL does'nt

I need an ERD created for any original database(can be on anything). It needs to be 3NF. I then need all the CREATE STATEMENTS, INSERT STATEMENTS(anything you can think of as long

how many hourse have been spent on a certain project

Create role named role_table that allows a user to create tables. Using role_table allow users kripa and reena to create tables. CREATE ROLE role_table; GRANT CREATE ANY TABLE