1. Object To Relation Mapping

2. Data Structure
Owner String name; String taxId; Account[] accounts; Account – is abstract String id; double balance; InterestBearingAccount extends Account double rate; int termDays; CheckingAccount extends Account double checkFee

3. 1:1 and 1:many Mappings in the Data Model
Owner – name : one to many Owner – taxId : one to one Owner – Account : one to many Account – id : one to one IntBearAcct – rate : ??? IntBearAcct – termDays: ??? intBearAcct – minBal : ??? CheckingAcct – checkFee: ???

4. Horizontal Partitioning
Each concrete class is mapped to a table
Owner
String name;
String taxId;
Account[] accounts;
Account – is abstract
String id;
double balance;
InterestBearingAccount extends Account
double rate;
int termDays;
CheckingAccount extends Account
double checkFee

5. Vertical Partitioning
Each class is mapped to a table
Owner
String name;
String taxId;
Account[] accounts;
Account – is abstract
String id;
double balance;
InterestBearingAccount extends Account
double rate;
int termDays;
CheckingAccount extends Account
double checkFee

6. Unification Each sub-class is mapped to the same table Owner
String name;
String taxId;
Account[] accounts;
Account – is abstract
String id;
double balance;
InterestBearingAccount extends Account
double rate;
int termDays;
CheckingAccount extends Account
double checkFee

7. Chalk Board Exercise
Assume that not only can an Owner have many Accounts, but an Account can have many Owners
How does this change the data model?
How Does It change database design?