The following figure shows an example of an EER diagram for a small private airport database that is used to keep track of airplanes, their owners, airport employees, and pilots. From the requirements for this database, the following information was collected: Each airplane has a registration number $[$Reg#$],$ is of a particular plane type $[$of$\_$type$],$ and is stored in a particular hangar $[$stored$\_$in$].$ Each plane$\_$type has a model number $[$Model$],$ a capacity $[$Capacity$],$ and a weight $[$Weight$].$ Each hangar has a number $[$Number$],$ a capacity $[$Capacity$],$ and a location $[$Location$].$ The database also keeps track of the owners of each plane $[$owns$]$ and the employees who have maintained the plane $[$maintain$].$ Each relationship instance in owns relates an airplane to an owner and includes the purchase date $[$Pdate$].$ Each relationship instance in maintain relates to an employee to a service record $[$service$].$ Each plane undergoes service many times; hence, it is related by $[$plane$\_$service$]$ o a number of service records. A service record includes as attributes the date of maintenance $[$Date$],$ the number of hours spent on the work $[$Hours$],$ and the type of work done $[$Workcode$].$ We use a weak entity type $[$service$]$ to represent airplane service, because the airplane registration number is used to identify a service record. An owner is either a person or a corporation. Hence, we use a union type $($category$)[$owner$]$ that is a subset of the union of corporation $[$Corporation$]$ and person $[$Person$]$ entity types. Both pilots $\{$Pilot$]$ and employees $[$Employee$]$ are subclasses of person. Each pilot has specific attributes license number $[$Lic$\_$Num$]$ and restrictions $[$Restr$]$; each employee has specific attributes salary $[$Salary$]$ and shift $\{$Shift$].$ All person entities in the database have data kept on their social security number $[$Ssn$],$ name $[$Name$],$ address $[$Address$],$ and telephone number $[$Phone$].$ For corporation entities, the data kept includes name $[$Name$],$ address $[$Address$],$ and telephone number $[$Phone$].$ The database also keeps track of the types of planes each pilot is authorized to fly $[$Flies$]$ and the types of planes each employee can do maintenance work on $[$Works$\_$on$].$

$1$: Map the EER diagram into relational schema.