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

What are the various properties of relational tables, What are the various ...

What are the various properties of Relational tables? Relational tables have 6 properties: 1. Each row is unique. 2. Column values are of the same kind. 3. Values are

Unix System Administration, What Command You Use What Day of the week were ...

What Command You Use What Day of the week were you born

State the rearranging the execution order for efficiency, Define the step -...

Define the step - Rearranging the Execution Order for Efficiency As we know that algorithm and data structure are closely related to one another, but data structure is conside

Types of locks, Types of Locks There are two necessary types of locks: ...

Types of Locks There are two necessary types of locks: Binary lock : This locking mechanism has two states for to a data item: locked or unlocked Multiple-mode loc

Field, examples of fields in a database

examples of fields in a database

aggregate functions-data manipulation language, Aggregate functions ...

Aggregate functions Some of these functions are min, count, max, and avg. These functions help in getting consolidated information from a set of tuples. Example:

List the steps for converting state diagram to the code, List the steps for...

List the steps for converting state diagram to the code. a) Finding major control path b) Finding the conditional statements  c) Finding the loops  d) Finding error ro

Advantages and disadvantages of using a database system, What are the advan...

What are the advantages and disadvantages of using a database system. Sol. Advantages of Database System (DBMS) :  (1) Data Redundancy and Inconsistency: Since differen

What is log shipping, What is Log Shipping? Log shipping is the method ...

What is Log Shipping? Log shipping is the method of automating the backup of database and transaction log files on a production SQL server, and then restoring them onto a stand

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