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 clustering file organization, Explain Clustering file organization ...

Explain Clustering file organization (i) Determine if a record of file is physically ordered on a nonkey field - that does not comprise a different value for each record - that

What is the full form of odbc, What is the full form of ODBC ? ODBC stand...

What is the full form of ODBC ? ODBC stands for Open Database Connectivity.

Data handling and research methods, Data Handling and Research Methods: ...

Data Handling and Research Methods: The dataset encompassing 130 participants contains several variables measuring detrimental health related behaviours referring to the use o

What are decision support systems, Question: (a) What are decision sup...

Question: (a) What are decision support systems, and what role do they play in the business environment? (b) Data mining is a knowledge discovery process of automated extr

Cartisian product, Explain the cartesian product in Database Management Sys...

Explain the cartesian product in Database Management System

ER diegrams, How to draw an ER diagram to a finance companz

How to draw an ER diagram to a finance companz

State the data flow diagram of functional model, State the data flow diagra...

State the data flow diagram of functional model Any action initiated by transition in the state diagram can be extended into an entire data flow diagram in functional model. Th

Creating views with check option-data control, Creating views with check op...

Creating views with check option : This option limits those updates of data values that cause records to go off the view. The following instance tells this in more detail: Examp

Record based logical models, Record based Logical Models: Use records as th...

Record based Logical Models: Use records as the key data representation components Examples: Relational Model: It shows data as well as relationship between data in the form

Design a query plan for distributed query, (a) Design a query plan for the ...

(a) Design a query plan for the following distributed query: An application at site B wants to compute a join of STUDENT ? Id=StudId TRANSCRIPT where STUDENT (Id,Major) is at site

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