A referential integrity constraint is used to make sure the values of a foreign key match a valid value of a primary key

What is keystoning?

a. the practice of maintaining variable costs at one-half of total fixed costs b. a method used for determining the point of elasticity c. a method of changing consumers' perceptions about price d. the practice of marking up prices by 100 percent

Which of the following is a valid source of secondary data?

A) personal letters and correspondence B) Internet search engines C) ethnographic research D) direct surveys E) interviews