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

Sql, sql is relationally complete-justify

sql is relationally complete-justify

Using literal character string-data manipulation language, Using Literal Ch...

Using Literal Character String Example: To print IS A as one string with column name employee SELECT ENAME || ' IS A ' || JOB AS "EMPLOYEE" FROM EMP;

What are decision support systems, Question: (a) What are decision sup...

Question: (a) What are decision support systems, and what role do they play in the business environment? (b) Data mining is a knowledge discovery process of automated extr

Mappings between levels and data independence, Mappings between Levels and ...

Mappings between Levels and Data Independence The 3 levels of abstraction in the database do not exist separately of each other. There must be some correspondence, or mapping

Need ssd information database completion for wp website, We are looking to ...

We are looking to find someone to prepare a database which improves upon the one we are using at present. The present database will be found here: Click on filter options and yo

Er model, explain the steps for reduction of er model into relational model...

explain the steps for reduction of er model into relational model?

Creating a view-data control, Creating a view: A query can be embed...

Creating a view: A query can be embedded within the CREATE VIEW STATEMENT A query can have complex select statements containing join, groups and sub- queries A quer

Information infrasctructure., what factors might influence a company to out...

what factors might influence a company to outsource its IT infrascture.

Find out the names of all employees from database, Find out the names of al...

Find out the names of all employees who work for first Bank Corporation from database. SELECT EMPLOYEE_NAME FROM WORKS WHERE COMPANYNAME = ‘First Bank Corporation';

Determine the derived attribute to avoid re-computation, Determine the Deri...

Determine the Derived attribute to avoid re-computation Each class box consists of an ordered list of attributes and operations, each represented as a next string. We can find

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