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

Define mysql_fetch_object(), What are the differences among MySQL_fetch_arr...

What are the differences among MySQL_fetch_array(), MySQL_fetch_object(), MySQL_fetch_row()? Mysql_fetch_object returns the result from the database like objects while mysql

Which is a valid sql type, Which is a valid SQL type? A valid SQL Shoul...

Which is a valid SQL type? A valid SQL Should be in CHARACTER it is should be NUMERIC and FLOAT.

Determine the strong and weak entity, Determine the Strong and Weak Entity ...

Determine the Strong and Weak Entity Based on the method of foreign key, there might be arise a situation when we have to relate an entity having a primary key of its own and a

Top down method and bottom up method, Evaluate, compare and contrast the tw...

Evaluate, compare and contrast the two methods of relational database design namely top down method and Bottom up method. What will be your choice if you are asked to select a meth

Private Tuition, Hi, Do you offer private tuition for DBMS?

Hi, Do you offer private tuition for DBMS?

Insertion anomaly-data redundancy, Insertion Anomaly: Inability to show ce...

Insertion Anomaly: Inability to show certain information-The primary key of the over relation be (enrolment number, Cno). Any new tuple to be inserted in the relation should have

Design and building a distributed information system, prototype of a distri...

prototype of a distributed information system for a national car part retail outlet chain.

Define null values, Define null values. In some cases a certain entity ...

Define null values. In some cases a certain entity may not have an applicable value for an attribute or if we do not know the value of an attribute for a certain entity. In the

Datawarehouse, Define a job scheduling strategy that will meet business req...

Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pictori

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