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

Database Management System, Assume that you are responsible for selecting a...

Assume that you are responsible for selecting a new DBMS product for Sohar Hospital

Write the queries in relational algebra, Problem: You are given the fol...

Problem: You are given the following schema 1. Flights(flno, from, to, distance) 2. Aircraft(aid, flno, aname, cruisingRange) 3. Certified(eid, aid) 4. Employees(eid, ena

Shadow paging, Describe the shadow paging technique.

Describe the shadow paging technique.

ERD, The entity type STUDENT has the following attributes: Student Name, Ad...

The entity type STUDENT has the following attributes: Student Name, Address, Phone, Age, Activity, and No of Years. Activity represents some campus-based student activity, and No o

Database project- inventory database for a hardware store, Normal 0 ...

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

What is primary index, Primary Index In primary index, there is a one-t...

Primary Index In primary index, there is a one-to-one relationship among the entries in the index table and the records in the major table. Primary index can be of two types:

Data modelling and normalization methodology, MOSS VALE is a town with 1500...

MOSS VALE is a town with 15000 inhabitants. The fire department wishes to develop a system that automates the despatch of fire engines to attend fires. The ERD below describes the

Transaction states, The following variant of the primary copy asynchronous-...

The following variant of the primary copy asynchronous-update replication protocol has been proposed for totally replicated systems. (a)  A transaction executing at site A updat

List the table modification commands in sql, List the table modification co...

List the table modification commands in SQL? A) Deletion B) Updates C) Insertion D) Update of a view

Discuss along with examples about several types of er model, Discuss along ...

Discuss along with examples about several types of attributes present in the ER model? Types of Attributes are: • SIMPLE attributes are attributes which are drawn from the ato

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