Example of Lossy Decomposition




Suppose you were using the following relation R = (SSN, Name, Address):
           R
SSN     Name      Address
1111    Joe       1 Pine
2222    Alice     2 Oak
3333    Alice     3 Pine

 Let R1 = (SSN, Name) and R2 = (Name, Address).
     R1                                                         R2
SSN     Name                           |     Name    Address
1111    Joe                               |     Joe     1 Pine
2222    Alice                             |     Alice   2 Oak
3333    Alice                            |     Alice   3 Pine



The join of R1 and R2 would produce the following table:
       R1 join R2
SSN     Name      Address
1111    Joe       1 Pine
2222    Alice     2 Oak
2222    Alice     3 Pine
3333    Alice     2 Oak
3333    Alice     3 Pine

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