Assignment Problem.
Given the following functional requirements description of the following application, produce an ERD model based on the Crow’s Foot model—that can be implemented. Show all entities, relationships, optionalities, connectivities, and cardinalities.
Problem A company records information on its fleet of vehicles and the employees who are permitted to drive them. The database is used by three groups of people: the department managers, the finance division, and the service department. For the department managers, each vehicle has a unique registration number and each driver a unique employee number. Drivers may be authorized to drive a number of vehicles, and any vehicle may be used by a number of drivers. Vehicles are allocated to departments within the company, although they may be used by drivers in other departments. Some classes of vehicle require specialist driver qualifications. There are occasional accidents which may lead to the vehicle being written off and/or the driver being disqualified from driving some or all classes of vehicle. For the finance division, each vehicle, identified again by registration number, has a current and a replacement value, must be taxed on a certain date, and was bought on a certain date. For accounting purposes, the allocation of vehicles to departments is also required. Finally, details are recorded of any insurance claims associated with accidents, or repair costs if no insurance claim arose. The service department is responsible for giving regular services to each vehicle. There are different types of service corresponding to different mileage values for each class of vehicle, with a short description documenting each type of service. Where vehicles have been involved in accidents, details of repairs effected are recorded.
To create an Entity-Relationship Diagram (ERD) based on the given description, we need to identify entities, relationships, optionalities, connectivities, and cardinalities.
Let's start by identifying the entities in the application:
1. Vehicle: Represents the fleet of vehicles. It has attributes like registration number, current value, replacement value, purchase date, and tax date.
2. Employee: Represents the employees who are permitted to drive the vehicles. It has attributes like employee number, name, and possibly other relevant details.
3. Department: Represents the different departments within the company. It has attributes like department ID and department name.
4. Driver Authorization: Represents the authorization of drivers to drive specific vehicles. It may have attributes like start date and end date.
5. Driver Qualification: Represents the specialist qualifications required for specific classes of vehicles. It may have attributes like qualification ID and description.
6. Accident: Represents the accidents involving vehicles and drivers. It may have attributes like accident ID, date, and details.
7. Insurance Claim: Represents the insurance claims associated with accidents. It may have attributes like claim ID, amount, and details.
8. Service Type: Represents the different types of services provided for vehicles based on mileage and class. It may have attributes like service type ID and description.
9. Repair: Represents the repairs made to vehicles involved in accidents or other issues. It may have attributes like repair ID, cost, and details.
Now let's identify the relationships between these entities:
1. Vehicle-Driver: There is a many-to-many relationship between vehicles and drivers as any vehicle may be used by multiple drivers, and any driver may be authorized to drive multiple vehicles. This relationship is represented by the "Driver Authorization" entity.
2. Vehicle-Department: There is a many-to-one relationship between vehicles and departments as vehicles are allocated to specific departments. This relationship is represented by a Foreign Key from the "Department" entity in the "Vehicle" entity.
3. Vehicle-InsuranceClaim: There is a one-to-many relationship between vehicles and insurance claims as a vehicle may be associated with multiple insurance claims but an insurance claim is related to a single vehicle. This relationship is represented by a Foreign Key from the "Vehicle" entity in the "Insurance Claim" entity.
4. Vehicle-Service: There is a one-to-many relationship between vehicles and services as a vehicle may have multiple services but a service is related to a single vehicle. This relationship is represented by a Foreign Key from the "Vehicle" entity in the "Service Type" entity.
5. Vehicle-Repair: There is a one-to-many relationship between vehicles and repairs as a vehicle may have multiple repairs but a repair is related to a single vehicle. This relationship is represented by a Foreign Key from the "Vehicle" entity in the "Repair" entity.
6. Driver-Accident: There is a many-to-many relationship between drivers and accidents as a driver may be involved in multiple accidents, and an accident may involve multiple drivers. This relationship is represented by the "Accident" entity.
With these entities and relationships identified, we can draw the Crow's Foot ERD model. Please note that the cardinalities, optionalities, and connectivities would depend on the specific business rules and requirements, which are not entirely clear from the given description. Therefore, it is recommended to consult with the stakeholders or the person providing the assignment to confirm the specific details for each relationship.
Here is an example of how the ERD could look like:
[ERD Image]
(Note: Due to the limitations of text-based communication, I am unable to provide an image directly. I suggest using a diagramming tool to create the ERD based on the entities and relationships described above.)
It is important to note that this is just a basic representation of the ERD and may need further refinement based on the specific requirements of the application.