This assignment is to practice reading and creating entity-relationship (ER) diagrams. Make sure the ER diagrams are legible and that relationships are properly documented, including cardinalities (1:1/ 1:n/ n:m), participation (total/partial) and primary keys.

Use the ER diagram provided to answer questions about a data base for Belmont Landscapes.

1. List two-non key attributes in the Customer Entity.

2. What is the cardinality of the Places relationship?

3. What is the participation of invoices in the Generates relationship?

4. Do you think the primary key for the Customer entity is a "natural" or "surrogate" key? Why?

5. Map the ER diagram to a relational schema to obtain the columns for the tables

6. What is the foreign key that creates a relationship between the Customer and Contract entities? Which table contains the foreign key, Customer or Contract?

7. What is the foreign key that creates a relationship between the Contract and Invoice entities? Which table contains the foreign key, Customer or Contract?

8. Explain the term "referential integrity" as applied to the relationship between the Contract and Invoice entities. Use sample data to explain how referential integrity could protect the integrity of the data.

firstName lastName phone date comparmy item custID Customer PlacesContractGenerates Invoice itemNumb address type city date state email