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

Which types of data supported by mysql, Which types of data supported by My...

Which types of data supported by MySQL for Time and Date formats?  MySQL supports a number of time and date column formats: Some of them are 1) DATE 2) DATETIME 3) TIM

What is called a query -execution engine, What is called a query -execution...

What is called a query -execution engine? The query implementation engine takes a query evaluation plan, implements that plan, and returns the answers to the query.

RDBMS, why data in an RDMS need to be normalised

why data in an RDMS need to be normalised

Security and integrity, Security And Integrity After Reading the concep...

Security And Integrity After Reading the concepts of database recovery in the last section, let us now deal with a vital concept that helps in minimizing consistency errors in

Vertical fragmentation, Vertical Fragmentation- Vertical fragmentation grou...

Vertical Fragmentation- Vertical fragmentation groups together only those attributes in a relation that are used jointly by various important transactions. A vertical fragment is d

Create student db and retrieve all student name in cs, Create a Student dat...

Create a Student database and Retrieve the names of all students majoring in ‘CS' Consider the following relational database: STUDENT (name, student#, class, major) COURSE (co

Illustrate the state model for the atm class, Illustrate the State model fo...

Illustrate the State model for the ATM class let us take state model for the ATM class given below in Figure showing state model of the ATM class and the pseudo code derived fr

Speedup query processing, Speedup Query Processing: A query that includes d...

Speedup Query Processing: A query that includes data at various sites can be split into sub-queries. These sub- queries can be implemented in parallel by various sites. Such parall

Normalization, Normalize the given relation to 3NF, justifying each step

Normalize the given relation to 3NF, justifying each step

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