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

Nested queries, Nested Queries Let us see some more complex queries in ...

Nested Queries Let us see some more complex queries in this section. Sub-queries: Some of the basic concerns of sub-queries are: A sub-query is a SELECT statemen

Explain degree of relation, Explain degree of relation? Degree of a Re...

Explain degree of relation? Degree of a Relation - The degree or arity of a relation is the number of attributes n of its relation schema.

How can we classify the operations on classes, How can we Classify the oper...

How can we Classify the operations on classes  This step fundamentally means all three models functional, object and dynamic (studied in last section) must be combined so that

Explain pipelining, Explain pipelining.        Ans: In order to describ...

Explain pipelining.        Ans: In order to describe pipelining in simple terms, think of it as breaking down processor functions into smaller and smaller parts. For instance,

Explain cursors in sql, Explain cursors in SQL? Cursors in SQL - An o...

Explain cursors in SQL? Cursors in SQL - An object used to store the output of a query for row-through-row processing through the application programs. Cursors are constructs

Extend the database, Now that she understands more about the benefits of da...

Now that she understands more about the benefits of databases, the play-scheme manager would like to extend the play-scheme database to include data for schools and instructors as

Central database schema, Consider an information system designed for an onl...

Consider an information system designed for an online company which provides IT products and services. These include desktops, laptops, networking products, IT books, parts, and te

Designing the hierarchy of a ldb?, What sorts of tables one can se in desig...

What sorts of tables one can se in designing the hierarchy of a LDB? Tables, which are having Foreign Key relations.

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

Report writing help on database mgmt, Report writing help on database mgmt ...

Report writing help on database mgmt Project Description: Use of Harvard referencing, critical analysis is required. Skills required: Academic Writing, Technical Writin

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