Question

Problem Statement:
Consider a mail order database in which employees take orders for parts from customers. The data requirements are summarized as follows:
• The mail order company has employees identified by a unique employee number, their first and last names, and a zip code where they are located.
• Customers of the company are uniquely identified by a customer number. In addition, their first and last names and a zip code where they are located are recorded.
• The parts being sold by the company are identified by a unique part number. In addition, a part name, their price, and quantity in stock are recorded.
• Orders placed by customers are taken by employees and are given a unique order number. Each order may contain certain quantities of one or more parts and their received date as well as a shipped date is recorded.
Design an Entity-Relationship diagram for the mail order database and enter the design using a data-modeling tool such as ERWin.

Answer 1

The ER diagram for the question is as follows:

Now, (X-X) is representing the relationship between two entities. For example, (0-N) means the 0 to N relationship between two entities. Now it's very easy to make the database using this entity relationship diagram. All the entities are table name and all the attributes are columns of the database. All the relationships are can be seen as foreign keys. The Unique ID is used as a foreign key to make a relationship between tables.