Relation instance or relation state, Database Management System

Assignment Help:

A relation instance indicates as r is a collection of tuples for a given relational schema at a exact point of time.

A relation state r of the relation schema R (A1,A2,..........AN), also denoted by r(R) is a set of n-tuples

r = {t1,t2,............tm}

Where each n-tuple is an ordered list of n values

t  =  1,v2,........, vn>

where every vi belongs to domain (Ai) or includes null values.

The relation schema is also known as  'intension' and relation state is also known as 'Extension'.


Related Discussions:- Relation instance or relation state

Fire dementpart, The State of NewYork certifies firefighters throughout sta...

The State of NewYork certifies firefighters throughout state and keep track all of them, as well as of the state’s fire departments. Each fire department has unique department numb

Explain five duties of database administrator, Explain five duties of Datab...

Explain five duties of Database Administrator? 1. DBA administers the three stages of the database and, in consultation along with the whole user community, sets up an defin

Explain the query processing, Explain the Query Processing  Data Query ...

Explain the Query Processing  Data Query Processing permits a user to report or analyze structured and unstructured data pulled from multiple data sources.

Explain transaction manager and their work, Explain Transaction manager and...

Explain Transaction manager and their work? Transaction Manager: Ensure the database remains in a constant (correct) state despite system failure, and in which concurrent trans

Designing a Human Resources Database LASA1, Scenario: You are a freelance ...

Scenario: You are a freelance database designer who has just been contacted by a small software development company named Altair Software. The president of the company has asked

What are the properties of transaction, What are the properties of transact...

What are the properties of transaction? There are three properties of transactions :- A)     Atomicity B)      Consistency C)       Isolation

Explain the dependency relationship of object oriented, Explain the depende...

Explain the dependency relationship of object oriented A dependency is a relationship which states that a change in specification of one thing can affect another thing, but n

Which model is record based logical model, Which model is record based logi...

Which model is record based logical model? Network Modelis basically known as record based logical model.

Write a short note on oracle instance, Write a short note on oracle Instanc...

Write a short note on oracle Instance? Oracle Instances: An instance is the (executed) Oracle software and the memory they use. It is the instance which manipulates the data s

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

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