What is inheritance, Database Management System

Assignment Help:

What is inheritance? Define it in detail?

 Inheritance

Inheritance can be at the levels of types, or at the level of tables we first consider inheritance of types, then inheritance at the level of labels.

Type inheritance

Assume that we have the following type definition for people

create type person

(name varchar(20)

address varchar(20))

Table inheritance

Create table people of person

The consistency requirements for sub tables are

1. Each tuple of the sub table can correspond to at most single tuple in each of its immediate sub tables.

2. SQL:1999 has an additional constraint that all the tuples corresponding to each other must be derived from single tuple .

 


Related Discussions:- What is inheritance

Write short notes on relational model, Write short notes on relational mode...

Write short notes on relational model   The  relational  model  uses a  collection of  tables  to show  both data  and the relationships between those  data.  The relational mo

Describe physical data independence, Describe Physical Data independence ? ...

Describe Physical Data independence ? Physical Data Independence - It is capacity to modify the internal schema without having to change conceptual schema. Therefore, the exter

Durability-transaction , Durability : This property necessitates that once ...

Durability : This property necessitates that once a transaction has committed, the changes made by it be never lost because of subsequent failure. Thus, a transaction is also a bas

Implementing a data mining algorithm, i need to implememnt a treee based mi...

i need to implememnt a treee based mining algorithm. do you have an expert that can do that?

Managing databases, Code an Oracle Database trigger to enforce the constrai...

Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department.

List the drawbacks of relational database system, List the drawbacks of rel...

List the drawbacks of relational database system A) Repetition of data B) Inability to s certain information.

Explain domain calculus, Explain Domain calculus Domain calculus is one...

Explain Domain calculus Domain calculus is one of the types of the relational calculus. The formal specification of the domain calculus was planned after the development of the

Data control, Identify the need and use of data control through problem sol...

Identify the need and use of data control through problem solving, illustration

Explain how the law ensures data protection and security, Question 1: (...

Question 1: (a) Explain the legal meaning of :- (i) Computer Service Person (ii) Data holding (b) Explain how the law ensures Data protection and Security. Qu

Differance between unordered and ordered file, Differance between Unordered...

Differance between Unordered and ordered file ? Unordered file do no has any sequence although ordered file has arranged in a few sequence and data are assigned in ordered form

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