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.