Data Modeling Using Erwin Software

This was a project I had done for a database design and development class.
Screenshots of my work are provided according to the requirements.
(As I am using the academic edition of Erwin, it does not allow for direct source file connection to Github.)

Project Instructions: View Here
Project Reflection and Explanation of Functional Dependencies: View Here
Erwin Software Info: View Here


Conceptual level of the entity relationship diagram displays the four independent, strong entities (Department, Supervisor, Employee, and Project). It also displays the bridging, associative entities between them (Department_Employee, Supervisor_Employee, and Project_Assignment) that are required to facilitate the many-to-many cardinalities. There is also the parent-child entity relationship seen between "Project" and "Task".


Logical level of the entity relationship diagram expands on the conceptual and shows the attributes of each entity and identifies which function as the primary or foreign keys.


Physical level of the entity relationship diagram expands on the logical and shows the formatted datatypes for each attribute compatible with MS Sql Server.


Physical EXTENDED Entity Relationship Diagram Level extends the original ERD by showing super-subtype entities. In this case, department and employee are the supertypes and the subtypes inherit their attributes and are disjointed (meaning an instance may not be part of two subtypes simultaneously).