1. Relational Database Design Relational Database Design
PROPERTY
ACCOUNT
MAINTENANCE
TENANT
OWNER
incur
rent
own 1 N M
(1, N)
(1, 1)
(0, N)
for
pay
Perform the complete transformation steps for the E-R Model
of the ‘Real Estate Agency’ described in Topic4. 1
Topic 5 : Relational Database Design

2. Relational Database Design
Solution
-- From Step1
OWNER ( Owner #, Owner Name, Owner Address)
PROPERTY ( Building#, Address, Value)
TENANT(Tenant#, Family Name, First Name, Contact Address, Phone#)
MAINTENANCE (Maintenance#, Date, Type, Cost)
ACCOUNT( Acct Receipt#, DateofPayment, TypeofAccount, AmountPaid)
-- Step2: No weak entity
-- Step3: no 1 To 1 relationship
-- Step3
-- Step4: 1 To N between OWNER and PROPERTY --
The PROPERTY relation is modified:
PROPERTY (Building#, Address, Value, Owner#)
Topic 5 : Relational Database Design

3. Relational Database Design
Solution
-- Step4: 1 To N between PROPERTY and MAINTENANCE --
The MAINTENANCE relation is modified to:
MAINTENANCE(Maintenance#, Date, Type, Cost, Building#)
-- Step4: 1 To N between TENANT and ACCOUNT --
The ACCOUNT relation is modified to:
ACCOUNT( Acct Receipt#, DateofPayment, TypeofAccount, AmountPaid,Tenant#)
-- Step4: 1 To N between PROPERTY and ACCOUNT --
The ACCOUNT relation is modified to:
ACCOUNT( Acct Receipt#, DateofPayment, TypeofAccount, AmountPaid,Tenant#,
Building#)
Topic 5 : Relational Database Design

4. Relational Database Design
Solution
-- Step5: M to N relationship between TENANT and PROPERTY --
The RENT relation is created:
RENT (Building#, Tenant#, LeasedPeriod, Bond)
-- Step6: no multivalued attribute.
-- Step7: no ternary relatiosnhip -
Topic 5 : Relational Database Design

5. Relational Database Design
Solution
-- Finally, the end result of the transformation can be listed as follows.
OWNER ( Owner #, Owner Name, Owner Address)
PROPERTY (Building#, Address, Value, Owner#)
TENANT(Tenant#, Family Name, First Name, Contact Address, Phone#)
MAINTENANCE(Maintenance#, Date, Type, Cost, Building#)
ACCOUNT( Acct Receipt#, DateofPayment, TypeofAccount, AmountPaid,
Tenant#, Building#)
RENT(Building#, Tenant#, LeasedPeriod, Bond)
Step 1
Step 4
Step 1
Step 4
Step 4
Step 5
Topic 5 : Relational Database Design