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 the term- periodic recomputation, Explain the term- Periodic recomp...

Explain the term- Periodic recomputation Periodic recomputation:  Base values are often updated in bunches. Sometimes, it is possible to just recompute all derived attributes p

Explain about foreign key, What is Foreign Key Foreign Key: Sometimes...

What is Foreign Key Foreign Key: Sometimes we may have to work with an attribute that does not have a primary key of its own. To recognize its rows, we have to use the primar

Graphical user interface tools, These are interactive interfaces, graphical...

These are interactive interfaces, graphical that hide the difficulty of the DBMS and query language behind an intuitive, simple to understand, and convenient interface. This permit

Critically evaluate the bulleted list of information, Critically evaluate t...

Critically evaluate the bulleted list of information-related items in this case study. How are each contradictory to the notion of being an information-literate knowledge worker?

Define the term domain, Define the term Domain. For each n every attrib...

Define the term Domain. For each n every attribute there is a set of permitted values known as the domain of that attribute.

Data analyzing and desing, Critically explained the benefits and limit...

Critically explained the benefits and limitations of different database technologies with proper examples

Multilevel indexing scheme, Multilevel Indexing Scheme Consider the ind...

Multilevel Indexing Scheme Consider the indexing scheme where the address of the block is consider in the index for each record, for a little file, this index would be little a

Schema, difference between internal schema and external schema in DBMS

difference between internal schema and external schema in DBMS

Explain the process-oriented decomposition, Breaking into Subsystems D...

Breaking into Subsystems Decomposition is a significant technique for coping with complexity based on idea of divide and conquers. In dividing a problem into sub problems, the

Domains, Every simple attribute of an entity type have a possible set of va...

Every simple attribute of an entity type have a possible set of values that can be attached to it. This is known as the domain of an attribute. An attribute cannot have a value out

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