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

Aggregation, Design a database for an airline.The database must keep track ...

Design a database for an airline.The database must keep track of customers and their reservations,flights and their status, seat assignment on individual flights and, the schedule

OLD HOME POLICIES, Write an sql statement to find what is the percentage of...

Write an sql statement to find what is the percentage of home policies which are from the state of Arizona out of all Home policies by Policy Value.

Differentiate between key and superkey, Differentiate between Key and super...

Differentiate between Key and superkey? Key and superkey - A key a single attribute or a combination of two or more attributes of an entity set in which is used to identify o

Working and processing files, 1.  Define each of the following IN YOUR OWN ...

1.  Define each of the following IN YOUR OWN WORDS: (a)   File: (b)   Record: (c)   Field: (d)   Primary Key: (e)   Secondary Key: 2.  A travel agency wants t

Write short notes on relational constraints, Write short notes on relationa...

Write short notes on relational constraints? Relational Constraints are: 1. NOT NULL 2. Unique 3. Primary key 4. Foreign key 5. Table check

Explain what is to be done during defining problem statement, Briefly expla...

Briefly explain what is to be done during defining problem statement. To define Problem Statement of a system, define what is to be done and how you can go to implement that. Y

What is a records management consultation, What is a records management con...

What is a records management consultation? Our organization is an authority for disseminating your specific requirements and giving you with a solution to effectively manage yo

Describe data manipulation language, Describe Data Manipulation language ? ...

Describe Data Manipulation language ? Data Manipulation Language (DML) - A data manipulation language is a language which enables users to access or manipulate data as organize

Database, . Ashutosh Dubey who is the director of Gyan Gurukul want a three...

. Ashutosh Dubey who is the director of Gyan Gurukul want a three-level schema architecture for the Gyan Gurukul Company that provide better security also design a data abstraction

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