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

What is the concurrency identification, Concurrency Identification Whi...

Concurrency Identification While designing analysis, model we map real world model into our analytical model. Real life objects are simultaneous in nature, but all the design

What is association, What is association? Give an example of association ...

What is association? Give an example of association Association is used for establishing relationships among classes. Association describe links among/between classes. For exa

Discuss the method for a hash file to expand shrink dynamic, Discuss the me...

Discuss the methods for a hash file to expand and shrink dynamically. What are the advantages and disadvantages of each? The hashing methods that permit dyanamic file expansi

Decompose the table - 3nf or bcnf, Decompose the table with the following ...

Decompose the table with the following description and functional dependencies into a set of equivalent tables normalized to 3NF or BCNF. A long-standing international treaty am

Database part of ldb?, Is it mandatory to declare all the tables in Report ...

Is it mandatory to declare all the tables in Report by the key word tables for all the tables that exist in the structure of LDB, and are being explained in the Database part of LD

What are the strategies of implementation of the statecharts, What are the ...

What are the different strategies of implementation of the Statecharts?  There are two strategies for implementation of state charts: i)   Basic Implementation Strategy

Explain the togaf framework for enterprise architectures, Question: (a)...

Question: (a) With the help of a diagram, explain the TOGAF framework for enterprise architectures. (b) Where would you position enterprise architectures in an enterpri

Define sequence, Define Sequence A sequence is a set of integers 1, 2, ...

Define Sequence A sequence is a set of integers 1, 2, 3 that are generated in order on demand. Sequences are regularly used in databases because lots of applications require ev

What does authentication refer, What does authentication refer? Authent...

What does authentication refer? Authentication refers to the task of verifying the uniqueness of a person.

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