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

A table joined with itself is called, A table joined with itself is called ...

A table joined with itself is called ? A table joined with itself is known as self join table. Normal 0 false false false EN-IN X-NONE X-NONE

Create student database and retrieve course taught by king, Create student ...

Create student database and retrieve course name taught by king? STUDENT (name, student#, class, major) COURSE (course name, course#, credit hours, department) SECTION (secti

MS Access 2010 - Form Updates Table, Hi there, Have an issue with my Databa...

Hi there, Have an issue with my Database. I have: TblOrderDetails and FmOrderDetails TblCircuit and FmCircuit Whenever I add data into the Form, it will update the table as expect

Explain superkey, Explain Superkey Ans: A superkey is described in the ...

Explain Superkey Ans: A superkey is described in the relational model of database organization like a set of attributes of a relation variable for which it holds that in all re

Which data manipulation command combines the records, Which data manipulati...

Which data manipulation command combines the records from one or more tables ? JOIN data manipulation command combines the records from one or more tables.

Describe the relational model, a) Distinguish between ‘database' and ‘Data...

a) Distinguish between ‘database' and ‘Database Management Systems (DBMS)'. b) List and briefly describe five potential benefits of the database approach compared to conventio

Replication-design of distributed databases, Replication : It is definite a...

Replication : It is definite as a copy of a relation. Every replica is stored at a dissimilar site. The alternative to replication is to store only single copy of a relation which

Why is database redesign necessary, Why is database redesign necessary? ...

Why is database redesign necessary? Database redesign is essential for two reasons. First, redesign is essential both to fix mistakes made during the initial database design. S

Update operations, The Update Operations : Update operations are used fo...

The Update Operations : Update operations are used for altering database values. The constraint violations faced by this operation are logically the similar as the problem faced

Explain traditional programming languages, How persistent programming langu...

How persistent programming languages differ from traditional programming languages? Database languages vary from traditional programming languages in that they directly manipul

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