Section 8 Quiz (Answer all questions in this section)

  1.   All systems must include functionality to provide logging or journaling in conceptual data models. True or False?
True  
False (*)
 
  2.   When a system requires that old values for attributes are kept on record, this is know as Journaling or Logging. True or False?
True (*)  
False

 
  3.   You are doing a data model for a computer sales company where the price of postage depends upon the day of the week that goods are shipped. So shipping is more expensive if the customer wants a delivery to take place on a Saturday or Sunday. What would be the best way to model this?  
Use a Delivery Day entity, which holds prices against week days, and ensure the we also have an attribute for the Requested Delivery Day in the Order Entity. (*)  
Allow them to enter whatever delivery charge they want.  
Update the prices in the system, print out the current prices when they change, and pin them on the company noticeboard.  
Email current prices to all employees whenever a price changes.


  4.   All systems must have an entity called WEEK with a holiday attribute so that you know when to give employees a holiday. True or False?   
True  
False (*)


  5.   Which of the following would be a logical constraint when modeling time for a City entity?
Cites may change their names and/or country association if the borders of a country change. (*)
Daily traffic patterns must be monitored to determine how many law enforcement officers are need
If you are doing a system for any French City, you would need security clearance.
People are born in the city and people die in the city.

 
  6.   When a relationship may or may not be transferable, depending on time, this is know as a/an: 
Non-transferable Relationship.  
Transferable Relationship  
Conditional Non-transferable Relationship. (*)  
Arc.

 
  7.   If you have an entity with a DATE attribute, in addition to other attributes that track date characteristics, you should create a DAY entity. True or False?
True (*)  
False

 
  8.   Modeling historical data is optional. True or False?
True (*)  
False

 
  9.   You must make sure all entities of a proposed system can fit onto one diagram. It is not allowed to break up a data model into more than one diagram. True or False? 
True  
False (*)


  10.   Which of the following statements are true for ERD's to enhance their readability. (Choose Two) 
The crows feet (many ends) can point whichever way is the easiest to draw.  
You must ensure that you have every single entity--even if hundreds of them exist--on one single, big diagram.  
Avoid crossing one relationship line with another. (*)  
It is OK to break down a large ERD into subsets of the overall picture. By doing so, you end up with more than one ERD that, taken together, documents the entire system. (*)

 
  11.   There is no point in trying to group your entities together on your diagram according to volume, and making a diagram look nice is a waste of time. True or False?
True  
False (*)

 
  12.   In an ERD, it is a good idea to group your entities according to the expected volumes. By grouping high volume entities together, the diagrams could become easier to read. True or False?
True (*)  
False

 
  13.   When modeling historical data the unique identifier is always made up of a barred relationship from the original two entities. True or False?
True  
False (*)

 
  14.   Historical data must never be kept. True or False?
True   
False (*)

 
  15.   Historical data should always be kept. True or False?  
True   
False (*)

Lanjutan... Database Design Section 9 Quiz

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