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

Fire dementpart, The State of NewYork certifies firefighters throughout sta...

The State of NewYork certifies firefighters throughout state and keep track all of them, as well as of the state’s fire departments. Each fire department has unique department numb

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

Sequences-data control, Sequences Sequences: Automatically produ...

Sequences Sequences: Automatically produce unique numbers Are sharable Are typically used to make a primary key value Replace application code Speed up t

Which data type can store unstructured data, Which data type can store unst...

Which data type can store unstructured data? Raw data type can store unstructured data.

Define clause in sql to specify query result must be sorted, The clause in ...

The clause in SQL which specifies that the query result should be sorted in ascending or descending order based upon the values of one or much more columns is Ans : Order by

What is meant by heuristic optimisation, What is meant by heuristic optimis...

What is meant by heuristic optimisation?Discuss the major heuristics that are applied during query optimisation.

Relational database, Convert the following ER - diagram (Entity Relationsh...

Convert the following ER - diagram (Entity Relationship Diagram) into a relational database (the primary keys are underlined): 2160_Convert the following ER - diagram into a

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

Type of views-data control, Type of views :  Simple views and Difficult ...

Type of views :  Simple views and Difficult Views Feature Simple Views Complex Views Number of tables One

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