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

What are the issues are formed while selecting a database, What are the Iss...

What are the Issues when Selecting a Database Issues when Selecting a Database Storage space requirement: A database requires about triple storage space of the actua

Query optimization in database system, Problem : AirwaysCentre, an inte...

Problem : AirwaysCentre, an international airline booking company currently uses a relational database system for their operations, which includes the following relations: P

Importance of file organisation in database, Importance Of File Organisatio...

Importance Of File Organisation In Database To execute a database efficiently, there are various design tradeoffs needed. One of the most vital ones is the file Organisation. F

Define data conversion, Define data conversion? Helpful to load data in...

Define data conversion? Helpful to load data into temporary staging tables. Then can write SQL code to do much of data processing. SQL code is simpler and faster to write than

Design a gennalization and specialization hierarchy for an a, Design a genn...

Design a gennalization and specialization hierarchy for an automobile sales company

SQL, Ask Write the SQL code that will create the table structure for a tabl...

Ask Write the SQL code that will create the table structure for a table named EMP _1. This table is a subset of the EMPLOYEE table. The basic EMP_1 table structure is summarized in

Transaction states, The following variant of the primary copy asynchronous-...

The following variant of the primary copy asynchronous-update replication protocol has been proposed for totally replicated systems. (a)  A transaction executing at site A updat

What are referential integrity constraints, What are referential integrity ...

What are referential integrity constraints? A value that appears in single relation for a given set of attributes also appears for a particular set of attributes in another rel

What is a view in sql and when can views be updated, What is a view in SQL?...

What is a view in SQL? When can views be updated? A view is a virtual table which consists of columns from one or more tables. Through it is same to a table; it is stored in

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