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

Explain stand alone query language in details, Explain Stand Alone Query La...

Explain Stand Alone Query Language in details? Stand alone Query Language - The query language that can be used interactively is known as stand alone query language. It does no

01a_ImportCasting.xlsx, 01a_Broadway_LastFirst_yyyy-mm-dd Capstone Exercise...

01a_Broadway_LastFirst_yyyy-mm-dd Capstone Exercises You work as a production assistant in the office of the Green Man Theatre. One of your duties is to maintain the company datab

Explain the fundamental concepts of object-orientation, Explain the Fundame...

Explain the Fundamental concepts of object-orientation Software developers, data base administrators (DBAs) need to be familiar with fundamental concepts of object-orientation.

Modelling and normalisation, Task Part A. Create an ERD from a business pro...

Task Part A. Create an ERD from a business problem. (50 marks) Read the following problem and complete the tasks listed below. THE ABS Blood Bank Australian Blood Services (ABS) i

What is persistency, What is persistency? Persistency ensures which dat...

What is persistency? Persistency ensures which data is stored and that after the object is no longer available (program stops running) the data will be available to other users

Write a query that uses the union operator, Write a Query that uses the UNI...

Write a Query that uses the UNION Operator 1. Use the Software Experts database to:   a. Display the first and the last name of all consultants who worked on any projects f

Describe association design of an object, Describe association design of an...

Describe association design of an object by giving one suitable example of it. The Design of Associations Associations are "glue" of advanced object oriented analysis and

Explain the disadvantages of using dbms, Explain the disadvantages of using...

Explain the disadvantages of using DBMS There could be a few disadvantages of using DBMS. As DBMS requires computers, we have to invest a good amount in acquiring the hardwa

Explain generalization and aggregation in e_r diagram, Explain the concept ...

Explain the concept of generalization and aggregation in E_R diagrams. Give one example for each one of them? Generalization: Consider extending the entity set account throug

Which of the operations constitute a basic set of operations, Which of the ...

Which of the operations constitute a basic set of operations for manipulating relational data? Relational algebra operations constitute a basic set of operations for manipulati

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