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

Define deadlock detection, Define Deadlock detection If a system does ...

Define Deadlock detection If a system does not employ a few protocols that make sure deadlock freedom, after that a detection and recovery scheme should be used. An algorithm

Describe about use case and external case in dfd, Describe about Use Case a...

Describe about Use Case and external case in DFD The processes are transformed those into the Use Case and external case in DFD has same characteristics which of an actor in O

Balance transfer, Scenario 1: Power goes out after the first instruction. ...

Scenario 1: Power goes out after the first instruction. What happens?

Traffic data management, This report identifies and outlines my CIS 499 pro...

This report identifies and outlines my CIS 499 project named Traffic Data Management  Systems (TDMS) .   My goal is to design a replica of all traffic issues to be implemented i

Define hot swapping, Define hot swapping? Hot swapping permits the remo...

Define hot swapping? Hot swapping permits the removal of faulty disks and changes it by new ones without turning power off. Hot swapping decreases the mean time to repair.

Explain the check clause, Explain the Check Clause The CHECK clause is ...

Explain the Check Clause The CHECK clause is employed to at the end of a CREATE TABLE statement specify table constraints. This is known as table-based constraint because it ap

How to insert data in your table from another table, How to Insert data in ...

How to Insert data in your table from another table? insert into e.g, To insert tuples from employee into N_emp created above, use following statement Insert into N_emp

Explain the form of the create view command, We define a view in SQL throug...

We define a view in SQL through using the create view command. To describe a view, we must provide the view a name and must state the query in which computers the view. The form of

In the architecture of a database system which external leve, In the archit...

In the architecture of a database system which external level used? In the architecture of a database system view external level used.

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