A) Allows you to track the history of attribute values, relationships, and/or entire entities
Which of the following is a logical constraint that could result from considering
how time impacts the storage of data?
A) End Date must be before the Start Date.
B) An ASSIGNMENT may only refer to a COUNTRY that is valid at the Start
Date of the ASSIGNMENT.
C) Dates have value only with a time component.
D) ASSIGNMENT periods can overlap causing the database to crash.
B) An ASSIGNMENT may only refer to a COUNTRY that is valid at the Start Date of the
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?
How do you know when to use the different types of time in your design?
If you are tracking employment dates for an employee, do you need to have an
"End Date" attribute?