7. • Object Relational Mapping Costs Time And Money
• Relational Database Table Rows Have No Intrinsic
Object Identity
• Mapping Inheritance Hierarchies To Relational
Schemata Involves Compromises
• Foreign Keys Can Only Reference One Table
• Object Relational Impedance Mismatch Vs Object
To Pseudo Relational Impedance Mismatch
Monday, May 14,
8. Semi-Structure Data
“Batman of Gotham City, MA died Friday at Arkham
Medical Center in Boston after a bout with cancer. He
was 66.
Born in Revere, he was raised and educated in Salem, MA.
He was a member of St. Mary’s Church in Salem, MA, and
is survived by his wife, Jane N., and two children, John A.,
Jr., and Lily C., both of Winchester, MA.
A memorial service will be held at 10:00 AM at St. Mary’s
Church in Gotham.”
Monday, May 14,
12. Schema Evolution
Varchar(20) Varchar(20)
Int Double
Varchar(20) Varchar(200)
Date dd/mm/YY Date YY/mm/dd
100M records/DB size = 2TB
Monday, May 14,
