Hello; I have an assignment about drawing an E-R diagram. I am struggling in Ide

Question

Hello;

I have an assignment about drawing an E-R diagram. I am struggling in Identifying some entity

"

Staff
Each Home Sweet Home local office has a manager responsible for overseeing the operations of the office. Home Sweet Home closely follows the performance of its managers, and notes the date that they assumed their position at their current local office. Each manager is allocated an annual car allowance and a monthly bonus payment based upon the Local Office’s performance.
Each Home Sweet Home local office has members of staff with the job title of Supervisor (sometimes called Senior Administrator). Supervisors are responsible for the day-to-day activities of a dedicated group of staff (minimum of five and a maximum of nine members of staff) responsible for the management of property for rent. The administrative work of each group of staff is supported by a PA (Personal Assistant).
Each member of staff is given a staff number, unique across all local offices. Information held on each member of staff includes the name (first and last name), address (street, city, zip code), telephone number, gender, date of birth, social security number (SSN), job title (position), salary, and the date the member of staff joined Home Sweet Home. Additional information held on staff with the job title of PA (Personal Assistant) is the typing speed.
It is company policy to record the details of the next-of-kin of members of staff, including the next-of-kin’s full name, relationship to the member of staff, address (street city, zip code), and telephone number. Only the details of a single next-of-kin are held for each member of staff."

for staff entity. is it correct to identify to have these sub and superclass ?

Also, I want to know if using the associative entity in "interview "is correct or not .

Local Offices Next-kin Staff PK-Kin's full name FK-staff number K-SerialN K-staff number Interview Date of IntervieW Customers Fk-property NO Property For Rent Personal Assistant K Customer No Managers PK Property_No Car Allowance Typing Speed ounss Payment Owners Property Visits PK Owner_No PK Rental No Type of owner K-Pro No Property Advertising FK-Property NO PK-Newspaper Name Business Name of business Private Owners Name

Explanation / Answer

The Answer is as Follow:

1) For the staff entity:

According to my opinion there are no issues to define the staff entity as Superclass and Subclass By defining the common properties like name, ssn no, address , telephone no, gender, DOB , salary etc. in the Superclass i.e. Staff and define different properties among different staff members defined in the subclasses of Superclass means Typing Speed in Personal Assistant entity , no of members of a group in Supervisor Entity etc..

2) For interview entity

It is totally incorrect to define the associative entity between Local Office and Customers. Because a customer wants to buy a product from Office not giving any interview. There may be some other relation among both of Local Office and Customers like provide services as simple relation between both. If You want to setup Interview entity you have to define different entities for candidates and held interview for them.

if there is any query please ask in comments...

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