What is an e-r model and draw an e-r diagram for the company, Database Management System

Assignment Help:

What is an E-R model? Draw an E-R Diagram for the company database with following Descriptions?

The company is organized within departments. Each department has a unique name and a unique number along with various locations.
A department controls a number of projects, every of that has a unique name, unique number and a single location.

We store each employees name, social security number, address, and salary. An employee is assigned to one department but might work on several projects that are not necessarily controlled through the similar departments.

We need to keep track of the dependents of each employee for insurance purposes. We remain each dependent's name, age and relationship to the employee.

Ans. An entity-relationship model (ERM) is an abstract conceptual representation of structured data. Entity-relationship modelling is a relational schema database modelling techniques, used in software engineering to generates a type of conceptual data model (or semantic data model) of a system, frequent a relational database, and its requirements in a top-down fashion. Diagrams created using this procedure are called entity-relationship diagrams, or ER diagrams or ERDs for short.


Related Discussions:- What is an e-r model and draw an e-r diagram for the company

What is transaction, What is transaction? Transaction is a unit of prog...

What is transaction? Transaction is a unit of program implementation that accesses and possibly updated several data items.

RDBMS, why data in an RDMS need to be normalised

why data in an RDMS need to be normalised

Describes the several relationship constraints, Describes the several relat...

Describes the several relationship constraints through giving suitable example? Constraints on relationships: There are two kinds of constraints on relationships. 1) Mapping

Explain the advantages of database management system, Advantages of Databas...

Advantages of Database management system Let us summarize the advantages. Reduction of Redundancy: This is perhaps the most important advantage of using DBMS. Redundancy i

Extended e-r features, Although, the essential features of E-R diagrams are...

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

What is the need for triggers, What is the need for triggers? Triggers ...

What is the need for triggers? Triggers are useful mechanisms for alerting humans or for starting particular tasks automatically when particular conditions are met.

What are shortcomings in structured approach, What are shortcomings in stru...

What are shortcomings in structured approach? Structured methodology treats data and their behaviours separately, and this makes it harder to isolate changes. If changes are re

Define integrity, (a) Explain briefly the three parts of a relational Model...

(a) Explain briefly the three parts of a relational Model. (b) Contrast the following terms with an appropriate example: (i) stored attribute v/s derived attribute (ii) en

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