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,..........A_N), also denoted by r(R) is a set of n-tuples

r = {t₁,t₂,............t_m}

Where each n-tuple is an ordered list of n values

t = 1,v₂,........, v_n>

where every v_i 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

Anomalies, define anomalies and different types of anomalies with example

define anomalies and different types of anomalies with example

Prove that a relation which is 4nf must be bcnf, Prove that a relation whic...

Prove that a relation which is 4NF must be BCNF. Ans Let R be in 4NF. Suppose it is not in BCNF. Hence, there exists an FD X→Y in R such that x is not a super key. Although

Can you scan double-sided documents and remove blank pages, Can you scan do...

Can you scan double-sided documents - and remove blank pages? Our software and imaging systems supports duplex scanning, at the same time scanning both sides of a page. Program

Write short notes on domain relational calculus, Write short notes on domai...

Write short notes on domain relational calculus The domain relational calculus uses domain variables that take on values from an attribute domain rather than values for whole

By which techniquestransaction processing is associated, By which technique...

By which techniquesTransaction processing is associated? Transaction processing is associated by producing detail, summary, or exception reports and recording a business activi

Data dictionary, The database is to record information about artists for a ...

The database is to record information about artists for a (music) production company. An artist is the name of a singer or band; the name of the artist, the year the artist started

NORRMALIZATION, Home based assignment Consider an ORDER table with the foll...

Home based assignment Consider an ORDER table with the following attributes: • Order Number (ONo),Customer Number (CNo),Customer Name (CNa),Item Number (INo),Unit Price (UP), Quant

Linked list, what is difference between circular inked lust and grunded lin...

what is difference between circular inked lust and grunded linked list

EER models, Ask question #MinimThe Georgia Tech Library (GTL) has approxima...

Ask question #MinimThe Georgia Tech Library (GTL) has approximately 16,000 members, 100,000 titles, and 250,000 volumes (an average of 2.5 copies per book). About 10 percent of the

What are called index-sequential files, What are called index-sequential fi...

What are called index-sequential files? The files that are ordered sequentially with a primary index on the search key are known as index-sequential files

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages