In this appendix we display the relational logical schema. The purpose of this is to show how the components fit together and especially to show the use of existence attributes. The domains have been omitted.
|Primary Key (Customer_Code)|
|Foreign Key (Hobby_Code references Hobby.Hobby_Code)|
|Relation Customer Exist|
|Primary Key (Customer_Code, Customer_Exist_Start)|
|Foreign Key (Customer_Code references Customer.Customer_Code)|
|Relation Customer Address Exist|
|Primary Key (Customer_Code, Customer_Address_Exist_Start) ...|