$3)$ identifying entities, attributes, and relationship types in a series of business rules and requirements.

$4)$ Model the identified entities, attributes, and relationships within a modeling tool $($like draw.io$).$

C$.$ Developing a model for a Piano Manufacturer$$s database $($Problem $5$ in our Exercise Sheet$)$:

Ebony and Ivory, a piano manufacturer, wants to keep track of each piano it makes. To achieve this, each piano is uniquely identified by a serial number and its manufacturing completion date. Each Piano is an instance of a specific model, and each model is uniquely distinguished by an identification number and a designated name.

To develop each Piano model, Ebony and Ivory relies on multiple piano designers, each of which may participate in the development of one or multiple pianos as their tenure progresses. It is crucial for Ebony and Ivory to keep track of the designers responsible for these models even if no attributes have been identified yet. Finally, not every model developed reach the manufacturing phase, and for a piano to be manufactured the model must have been approved first.

$1.$ Please draw a model of the needed database including the inferences made above $($entities$,$ attributes, and relationships$).$

D$.$ Expanding our model for the Piano Manufacturer$$s database $($Problem $6$ in our Exercise Sheet$)$:

Continuing with our modeling of the Piano Manufacturer$$s database, we learn that:

Ebony and Ivory $($see $($problem $5)$ above$)$ employs piano technicians who are responsible for inspecting each piano before shipments are sent to the customers. Each piano must be go through at least $2$ inspections which are carried out by technicians $($who are themselves identified by their employee number$).$ For each separate inspection, the company needs to record its date and a quality evaluation grade.

$2.$ Please draw a model of the needed database including the inferences made above $($entities$,$ attributes, and relationships$).$

E$.$ Finalizing our model for the Piano Manufacturer$$s database $($Problem $7$ in our Exercise Sheet$)$:

As we present our proposal to the board of "Ebony and Ivory$,$ we are informed that there are additional considerations needed for the database. Specifically, we learn that:

The piano technicians $($see $($problem $6)$ above$)$ have a hierarchy of reporting relationships: some technicians have supervisory responsibilities in addition to their inspection role and have at least one but potentially multiple other technicians report to them. The supervisor technicians themselves report to the chief technician of the company who has no supervisors above.

Please answer the following questions to add the final touches to the database model:

$3.$ Please draw a model of the needed database including the inferences made above $($entities$,$ attributes, and relationships$).$

$4.$ Take the models built for the last three problems $($the models made for $$Ebony & Ivory$)$ and combine them so that we can present the full database model to the Board of the company. Please add your full model below: