Database Systems - design ERD ( Entity-Relationship diagram )

You are required to develop a simple database application for a small recruiting firm that wishes to keep track of all the employees at the firm; storing details about their name, phone numbers, hiredate, Gender, and Date of Birth. The firm has many departments and there are 5 to 20 employees in each department. The department information includes department name, description and total number of employees in that department. The company also provides vehicles for some of its employees. An employee maybe allocated one car. To ensure timely maintenance of vehicle, the company would like to store the following details of the vehicle: make, model, next_maintenance_date.

Each employee has a position (manager, accountant, administrator, clerk, etc.). Various allowances are allocated to each position. For example, the managers have fuel allowance, house allowance, social allowance and managers allowance. On the other hand, the administrators have house allowance and social allowance. Clerks have social allowance and uniform allowance. The name and description of each allowance needs to be stored.

The database keeps track of all Projects in the organization. Each department is assigned to one or more project. Project can be assigned to one or more department (Interdisciplinary projects).

Each Employee has his own credentials to login into the system to manipulate the database. The credentials are stored in a table (Login). You will also need a table to store transactions (Transaction Date/Time, User Name, Job, and Employee Number).

The system must store employees grades. Each employee will have a grade (Example A, B, C). The grade should have a predefined salary range.

The system also keeps track of employees bonuses through storing the name, job, commissions, and salary.

You need to have the following constraints in your system: The employees salary should be between the grade range (Example: Grade A -Salary between 30000-50000). Employees phone number, Hiredate, Date of Birth should not be empty. The age should between 18and 60.Vehicle next maintenance is within 3month of current date.Each position should not exceed the predefined allowances.The System will need a constraint for Gender (M,F). The Username must be Unique in Table Login..

Part A: Include the following before drawing the ERD:

a.Identify all Entities and attributes

b.Identify Primary key and Foreign Key in each table/Entity

c.Identify the Relationships between Entities.

d.Resolve any M:N relationship between the entities.

e.Mapping of relations to tables.

Part B: Draw the ERD using any Data ModellingSoftware.