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

Cluster analysis project, (a) Data Mining Process : In the context of t...

(a) Data Mining Process : In the context of this cluster analysis project , and in your own words , explain how you would execute the first stage of data mining, namely the "P

Which language used in application programs for request data, Which languag...

Which language used in application programs to request data from the DBMS is referred? Language which is used in application program is DML to request data from the DBMS is ref

Whst is logical schema, Whst is logical schema ? Logical schema is the ...

Whst is logical schema ? Logical schema is the entire database.

RDBMS, DISADVANTAGES OF RDBMS

DISADVANTAGES OF RDBMS

4, explain the level architectures of the database management system

explain the level architectures of the database management system

Forward recovery (redo), Forward Recovery (Redo): In this system the commit...

Forward Recovery (Redo): In this system the committed changes made by a transaction are reapplied to a previous copy of the database.                          In simpler

single products ordered, For Colorado customers calculate the number of si...

For Colorado customers calculate the number of single products ordered. If a product is purchased on multiple orders, it should be counted only single time. The result should conta

Difference between a composite key and attribute, Question: (a) Discuss...

Question: (a) Discuss the difference between a composite key and a composite attribute. How would each be indicated in an E-R diagram? Support your answer with appropriate exam

Entity relationship diagram, The Enhanced Entity Relationship Diagram (ERD)...

The Enhanced Entity Relationship Diagram (ERD) produced with a drawing or case tool. Your EERD must use a ''standard'' notation style such as Crows Foot or Chen. Please note that t

Er model, There are a number of possible solutions to the open ended brief....

There are a number of possible solutions to the open ended brief. One of the simple ones is shown here without the PKs and FKs. It is important to think of how a number of tasks

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