Ordering of tuples, Database Management System

Assignment Help:

In a relation, tuples are not inserted in any definite order. Ordering of tuples is not defined as a part of a relation definition. Though, records may be structured later according to some attribute value in the storage systems. For instance, records in PERSON table may be structured according to PERSON_ID. Such organisation or data depends on the requirement of the underlying database application. Though, for the purpose of display we may get them displayed in the sorted order of age. The following table is sorted by age. It is also worth states here that relational model does not permit duplicate tuples

PERSON

PERSON_ID      NAME                                 AGE              ADDRESS

2                           Sharad Gupta                       33                  Pocket 2, Mayur Vihar.

1                           Sanjay Prasad                      35                  b-4,Modi Nagar

3                           Vibhu Datt                           36                  c-2, New Delhi

Super Keys, Candidate Keys and Primary Keys for the Relations

As discussed in the last section ordering of relations does not matter and all tuples in a relation are unique. Though, can we uniquely recognize a tuple in a relation? Let us talk about the concepts of keys that are primarily used for the purpose as above.


Related Discussions:- Ordering of tuples

What are audit trails, What are audit trails? An audit trail is a log o...

What are audit trails? An audit trail is a log of all alters to the database along with information like which user performed the change and when the alter was performed.

What is the difference between primary key and a unique key, What's the dif...

What's the difference between a primary key and a unique key? Both primary key and unique key enforces uniqueness of the column on which they are explained. But by default prim

Search the name department number and salary of employees , Example : Searc...

Example : Search the name, department number and salary of employees drawing minimum salary in that department. SELECT ENAME, SAL, DEPTNO  FROM EMP WHERE SAL IN (SELECT MI

The third normal form (3nf), The Third Normal Form (3NF) Even though, t...

The Third Normal Form (3NF) Even though, transforming a relation that is not in 2NF into a number of relations that are in 2NF take out many of the anomalies, it does not neces

Describe the association - design, Describe the Association: Design  ...

Describe the Association: Design  Before we describe association design let us define association "Association is set of links between two objects in the object model". It is

Explain the components of database system in details., Explain the compone...

Explain the components of Database System in details.

Mixed fragmentation, Mixed fragmentation: Sometimes, horizontal fragmentati...

Mixed fragmentation: Sometimes, horizontal fragmentation or vertical fragmentation of a database schema by itself is insufficient to sufficiently distribute the data for some appli

What are the features of embedded sql explain, What are the features of emb...

What are the features of embedded SQL? Explain. Embedded SQL - SQL could be implemented within two ways. It can be used interactively or embedded in a host language or throu

What is trigger, What is Trigger? Trigger: A database trigger is proced...

What is Trigger? Trigger: A database trigger is procedural code which is automatically executed in response to specific events on a particular table in a database. Triggers can

Define deadlock avoidance, Define Deadlock avoidance These protocols a...

Define Deadlock avoidance These protocols as well ensure that the system will never enter a deadlock state although the way it is done is different from deadlock prevention. I

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