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

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

Secondary indexes, Secondary Indexes Let consider the student database ...

Secondary Indexes Let consider the student database and its clustering index and primary (only one will be applicable at a time). Now consider the state when the database is to

Explain the isa relationship, Explain the ISA relationship Answer: IS...

Explain the ISA relationship Answer: ISA relationship - ISA notation is employed in generalization/ specialization to depict relationship among lower and higer level entity s

Create a table for database transformation , Step 1 . Using Oracle, create ...

Step 1 . Using Oracle, create the tables identified in the preferred solution for Assignment 2. Technicians (ZipCode, TechnicianID, FirstName, LastName, Street, City, State, Home

Critically evaluate the bulleted list of information, Critically evaluate t...

Critically evaluate the bulleted list of information-related items in this case study. How are each contradictory to the notion of being an information-literate knowledge worker?

Data warehousing and business intelligence, I need help with data warehousi...

I need help with data warehousing and business intelligence course project about designing a data warehouse for a jewelry company that does not have one

What is view in sql, What is view in SQL? How is it defined? Any relati...

What is view in SQL? How is it defined? Any relation that is not part of the logical model, but is made visible to a user as a virtual relation is known as a view. We descri

Define the terms ddl and dml, Define the terms i) DDL ii) DML DDL: Data...

Define the terms i) DDL ii) DML DDL: Data base schema is particular by a set of definitions expressed by a special language known as a data definition language. DML: A data

Convert the erd into its relevant relational schema, Question: Describe...

Question: Describe briefly the three parts of the Relational Model. (a) The term integrity refers to the accuracy or correctness of the data in the database. Define the fol

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