ER Diagram

 

ONLINE ORDER INFORMATION SYSTEM

 

A common business document is and order form.   Orders are an integral part of any sales data base. In this exercise we will build an ER Diagram to represent the entities, attributes and relationships of a common order.

Consider the following sample order

 

 

Sample order form

ORDER NUMBER: __0500260____                                                DATE   01/24/2015

 

 

FROM:          Acme Manufacturing                                      Cust ID:  A231

                        240 Broward Boulevard

                        Yuma, Arizona 89026

                        C/o Wiley Coyote

SHIP TO:

 

 

 

ITEM #           QTY               Cat. #              DESCR.                     UNIT PRICE

1                      16                   135608            Canon Balls                 $ 54.99

2                      100                  982345            dynamite sticks           $ 5.89

3                          1                  359265            Road Runner trap       $249.99

 

 

                                                                                    Total Price      $1718.83

In this sample we can see that there is;

1.     Information about the order

2.     Information about the customer

3.     Information about the items ordered.

Exercise:

1.     List the entities and their attributes.

2.     List any relationships that may exit. Name the entities and the relationship

3.     Assign cardinality to each relationship.

4.     Draw the ER diagram.