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# 1
A real estate company uses a database to store information about customers, property, and contracts.
The following relations are used in the database:
Customer:
* Customer number (unique)
* name
* mailing address
* Balance
* lawyer name
* Discount
Contract:
* Customer number (unique)
* Agent number (unique)
* Property_ID (one per contract)
* Date of contract
* Property addresses
* Property value
* Type
* Number of rooms
* Land size
* Built size
* Tax value
The following functional dependencies apply:
* customer_no -> name
* customer_no -> mail_address
* customer_no -> balance
* customer_no -> lawyer_name
* customer_no -> discount
* {customer_no, Agent_no} -> propert_id
* {customer_no, Agent_no} -> date_contract
* property_id -> property_address
* property_id -> value
* property_id -> type
* property_id -> number_rooms
* property_id -> land_size
* property_id -> built_size
* property_id -> tax_value
Transform these relations into 3NF (please use only the attributes described above, and do not add any new attributes).
Normal forms:
1. 0 multi-valued attributes
2. 0 functional dependencies
3. 0 transitive dependencies
Before:
* Customers(_id_, name, mail_address, balance, lawyer_name, discount)
* Contract(_id_, customer_id, agent_id, date_of_contract, property_address, property_value, type, number_of_rooms, land_size, built_size, tax_value)
After:
* customers(id, name, mail_address, balance, lawyer_name, discount)
* contracts(id, customer_id, agent_id, property_id, date_of_contract)
* properties(id, address, value, type, number_of_rooms, land_size, built_size, tax_value)
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