Discussion Questions: 75 to 150 words
Referential integrity “rules” trigger some cleanup of your data when insertion, update, or deletion events would typically cause data anomalies. But the word “trigger” has its own place in database design and implementation. Research the concept of a “trigger” and compare and contrast “trigger” events with referential integrity rules.
Discuss the concept of the intersection table. Why is it needed in many to many relationships? Why is intersection data needed?
Page 154 exercises 1 and 2
Be sure to normalize the data tables for both databases to 3NF
You may submit a single Word document with your models pasted in or as separate PDF files representing each model.
1. Leslie’s Auto Sales has a relational database with which it maintains data on its salespersons, its customers, and the automobiles it sells. Each of these three entity types has a unique attribute identifier.
The attributes that it stores are as follows:
• Salesperson Number (unique), Salesperson Name, Salesperson Telephone, Years with Company
• Customer Number (unique), Customer Name, Customer Address, Value of Last Purchase From Us
• Vehicle Identification Number (unique), Manufacturer, Model, Year, Sticker Price Leslie’s also wants to keep track of which salesperson sold which car to which customer, including the date of the sale and the negotiated price. Construct a relational database for Leslie’s Auto Sales.
2. The State of New York certifies firefighters throughout the state and must keep track of all of them, as well as of the state’s fire departments. Each fire department has a unique department number, a name that also identifies its locale (city, county, etc.), the year it was established, and its main telephone number. Each certified firefighter has a unique firefighter number, a name, year of certification, home
telephone number, and a rank (firefighter, fire lieutenant, fire captain, etc.) The state wants to record the fire department for which each firefighter currently works and each firefighter’s supervisor. Supervisors are always higher-ranking certified firefighters.
Construct a relational database for New York’s fire departments and firefighters.