Sketch the ER diagram and a relational scheme for a real estate management system that controls information about customers, properties and the sell and buy procedures that are done in the company.

$$Each property has a registration number at the ministry that is dedicated for that property which could be a house or a land. Each property has an address that contains the street, city and postal code.

$$For each land we should register the access road, however for a house we should register number of rooms

$$Each buying operation will be accompanied with detailed bill that contains the date of buying the property, the total price to be paid and the different payments that the customer should pay with the due date for each payment.

$$Each payment has a number $($payment $1,$ payment $2,$ payment $3,$ etc$)$ and is usually related to a given bill.

$$A customer has a unique SSN with different phone numbers; however, a phone number can be related to a single customer