Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Modeling Change: Time
(Answer all questions in this section)
1. When you add the concept of time to your data model, you are: Mark for Review
Simplifying your model.
Adding complexity to your model. (*)
Just changing the model, but this does not change the complexity of it.
None of the above.
2. It is desirable to have an entity called DAY with a holiday attribute when you want to track special holidays in a payroll system. True or False? Mark for Review
3. What is the benefit to the users of a system that includes "time," e.g. Start Date and End Date for Employees? Mark for Review
Increased usability and flexibility of a system; we can the trace e.g. the different managers an employee had over time. (*)
System becomes 100% unstable; allows users to log on and log off at will.
Users are able to create complex programs in support of this component.
Reporting becomes nearly impossible, users enjoy this.
4. How do you know when to use the different types of time in your design? Mark for Review
The rules are fixed and should be followed
It depends on the functional needs of the system (*)
You would first determine the existence of the concept of time and map it against the Greenwich Mean Time
Always model time, you can take it out later if it is not needed
5. Which of the following would be a logical constraint when modeling time for a country entity? Mark for Review
People have births and deaths in their countries that must be tracked by the system.
If you are doing a system for France or Germany, you would need security clearance.
Countries may need an end date in your system, because they can change fundamentally over time, e.g. Yugoslavia. (*)
You need a constant record of countries, because they are still countries, even if leadership changes over time, e.g. France, USA and most other countries.
6. Modeling historical data produces efficient ways for a business to operate such as: Mark for Review
Modeling historical data does not help a business.
Providing valuable information via reports to management . (*)
Keeping track of holiday dates.
Employees can work in two time zones.
7. If you are tracking employment dates for an employee, do you need to have an "End Date" attribute? Mark for Review
Yes, because you always need an end date when you have a start date
No, because an end date is usually redundant
Yes, if the company wants to track employee information, like multiple start and end dates (*)
No, not if the company likes the employee