Extended e-r features, Database Management System

Assignment Help:

Although, the essential features of E-R diagrams are enough to design many database situations. Though, with more difficult relations and advanced database applications, it is need to move to enhanced features of E-R models. The three such features are:

  • Generalisation
  • Specialisation, and
  • Aggregation

In this part, we have described them with the help of an example. More detail on them are available in the further readings and MCS-043.

Example: A bank has an account entity set. The accounts of the bank can be of two parts:

  • Savings account
  • Current account

The statement as above shows a specialisation/generalisation hierarchy. It can be shown as

1135_Extended E-R features.png

Figure: Generalisation and Specialisation hierarchy


Related Discussions:- Extended e-r features

Database Management System, Assume that you are responsible for selecting a...

Assume that you are responsible for selecting a new DBMS product for Sohar Hospital

Describe embedded query language, Describe Embedded Query Language? Emb...

Describe Embedded Query Language? Embedded Query Language - A query language (e.g., SQL) can be implemented in two ways. It can be used interactively or embedded within a host

Explain authorization and integrity manager, Explain Authorization and Inte...

Explain Authorization and Integrity Manager ? Authorization and Integrity Manager: Tests for the satisfaction of integrity constraints and checks the authority of users to acce

What is data integrity, What is data integrity? Ans: It is the data con...

What is data integrity? Ans: It is the data consisted of in database that is accurate and consistent.  (Data integrity means that the data should be valid as per to the give

Explain trigger, Explain trigger? Trigger: A database trigger is proc...

Explain trigger? Trigger: A database trigger is procedural code which is automatically executed within response to certain events on a particular table in a database. Trigger

Explain the difference between drop and delete, Explain the Difference betw...

Explain the Difference between DROP and DELETE DELETE deletes one or more than one tuples of a particular relation from the database. DROP is employed to remove a table from th

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 called mirroring, What is called mirroring? The simplest approa...

What is called mirroring? The simplest approach to introducing redundancy is to duplicate each disk. This method is called mirroring or shadowing.

Explain discretionary access control, Problem: (a) Given the following ...

Problem: (a) Given the following relation: Stats(Name,Sex,Children, Occupation, Salary, Tax, Audits) Write SQL code to define the following security constraints: (i) User

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