Databases Reference
In-Depth Information
Figure 4-19
OFFICE
*
Office Number
Telephone
Size
Works in
SALESPERSON
CUSTOMER
Salesperson
Number
Salesperson
Name
Commission
Percentage
Year of Hire
Customer
Number
Customer
Name
HQ City
*
*
Sells to
Sells
Quantity
Works for
PRODUCT
CUSTOMER
EMPLOYEE
Product
Number
Product
Name
Unit Price
*
Employee
Number
Employee
Name
Title
*
General Hardware E-R diagram.
right of the SALESPERSON entity box in the E-R diagram, we see a one-to-many
relationship (“sells to”) between salespersons and customers. The database then
includes a CUSTOMER table with the Salesperson Number attribute as a foreign
key because Salesperson is on the “one side” of the one-to-many relationship and
Customer is on the “many side” of the one-to-many relationship.
