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

Explain derived and non-derived attribute, Explain Derived and Non-Derived ...

Explain Derived and Non-Derived Attribute? In few cases, two or more attribute values are related, for instance, Age and BirthDate attributes of a person. For specific person e

What are the problems in database normalization, What are the problems if o...

What are the problems if one were not to normalize?  When do these problems surface?           Ans:  Database normalization, sometimes considered to as  canonical synthesis, is

Recovery techniques, Recovery Techniques: After Reading the types of failur...

Recovery Techniques: After Reading the types of failures and database errors, let us talk about how to recover from the failures. Recovery can be complete using/restoring the previ

Need for multiple access paths, Need for Multiple Access Paths In pract...

Need for Multiple Access Paths In practice, most of the online information systems need the support of multi-key files. For example, consider a banking database application hav

Data, Explain three main attributes of data.

Explain three main attributes of data.

How does the system cope up with a record crash, How does the system cope u...

How does the system cope up with a record crash when recovery is going on after the first crash? Ans:  In a system the undo and redo operations are needed to be idempotent to c

What is dml (data manipulation language)?, This language that enable user m...

This language that enable user manipulate to or access data as organized by appropriate data model. Low level or Procedural DML : DML needs a user to specify what data ar

Define seek time, Define seek time. The time for repositioning the arm ...

Define seek time. The time for repositioning the arm is known as the seek time and it enhances with the distance that the arm is known as the seek time.

Relationships, Let us first describe the term relationships. What Are Re...

Let us first describe the term relationships. What Are Relationships? A relationship can be defined as: A set of associations or connection, or A rule for communic

Need for client server computing, Need for Client Server Computing- Client/...

Need for Client Server Computing- Client/Server (C/S) architecture includes running the application on multiple machines in which every machine with its component software tackles

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