1. Order Database – ER Diagram
By James Jennings

2. Designing Databases with Entity Relationship Diagrams
Step 1: Define Entity Classes and Primary Keys
Step 2: Define Relationships Among Entity Classes
Step 3: Define Attributes for each Table
Step 4: Create Database

3. Step 1: Define Entity Classes and Primary Keys
Customer
CustomerID
Product
ProductID
Order
OrderID
Business Rules
Customer may have multiple orders
Customers may have no orders.
Each order has one Customer
Each order must have a Customer
An Order must have one product
An order may have multiple products
A product may have multiple orders
A product may have no orders

4. Step 2: Define Relationships Among Entity Classes
CUSTOMER
ORDER
PRODUCT

5. Step 3: Define Attributes for each Table
Customer
CustomerID
FirstName
LastName
Address
Major
Location
Gender
Product
ProductID
ProductName
Price
BatchSize
Description
Type
Order
OrderID
Customer
Date
Product
Quantity

6. Step 3: Define Attributes for each Table
Customer
CustomerID
FirstName
LastName
Address
Major
Location
Gender
Product
ProductID
ProductName
Price
BatchSize
Description
Type
OrderID
OrderItem
OrderID
ProductID
Quantity
Order
OrderID
CustomerID
Date
ProductID
Quantity

7. Step 2: Define Relationships Among Entity Classes
CUSTOMER
ORDER
OrderItem
PRODUCT

8. Step 4: Create Database