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

Determine that the checkpoints are a part of, 1. Determine that the Checkpo...

1. Determine that the Checkpoints are a part of  Ans: Checkpoints are a part of Recovery measures

3NF Normalization, Need 2 projects completed in 3NF format.

Need 2 projects completed in 3NF format.

What is cross product, What is Cross Product? Simply Cross product is B...

What is Cross Product? Simply Cross product is Binary Operator

What is cardinality ratio, What is Cardinality Ratio? Cardinality Rati...

What is Cardinality Ratio? Cardinality Ratios - The cardinality ratios for relationship kinds specifies the maximum number of relationship instances in which an entity can pa

What is the function of io/m signal in the 8085, What is the function of IO...

What is the function of IO/M signal in the 8085? It is a status signal. It is used to differentiate among memory locations and I/O operations. When this signal is low (IO/M = 0

What is multivalued attribute, What is Multivalued Attribute? Multival...

What is Multivalued Attribute? Multivalued Attribute - Multivalued attribute might have more than one value for an entity. For instance, PreviousDegrees of a STUDENT.

Define control files, Control Files : The redo and control files logs supp...

Control Files : The redo and control files logs support the rest of the architecture. Every database must have at least one control file, although you have more than one to guard

What is meant by log-based recovery, What is meant by log-based recovery? ...

What is meant by log-based recovery? The most widely used structures for recording database changes is the log. The log is a sequence of log records, recording all the update a

Define ssn of salesman by using database of business trips, Consider the su...

Consider the subsequent relations for a database which keeps track of business trips of salespersons in a sales office: SALESPERSON (SSN, Name, start_year, Dept_no) TRIP (SSN, Fr

Define page, Define page. The database is partitioned into some number ...

Define page. The database is partitioned into some number of fixed-length blocks, which are referred to as pages.

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