Class O2.S1 (Duration, Interval, Computed)


=centercr @ []QUERY Q 3.1.1: Find the times when persons with a shorter employment in the Toy department than DI were employed in the Book department.
ANSWER: ``{ [4/1/87 - now]}''
CATEGORY: (None, Element, Union) / (Duration, Element, Computed) / (=, Constant)


=centercr @ []QUERY Q 3.1.2: Find the employment periods of persons that made 40K for a longer time than DI made 40K.
ANSWER: ``{ [2/1/82 - 1/31/87], [4/1/87 - now]}''
CATEGORY: (None, Element, Union) / (Duration, Element, Computed) / (=, Constant)


=centercr @ []QUERY Q 3.1.3: Find the starting times in the Book department of persons which possessed the Filing skill for a longer time than DI.
ANSWER: ``{ 4/1/87}''
CATEGORY: (None, Element, Derived) / (Duration, Element, Computed) / (=, Constant)


=centercr @ []QUERY Q 3.1.4: Return the times when persons employed a shorter time than DI acquired a skill.
ANSWER: ``{ 1/1/82, 4/1/82, 6/1/84, 1/1/85, }''
CATEGORY: (None, Element, Derived) / (Duration, Element, Computed) / (=, Constant)


=centercr @ []QUERY Q 3.1.5: Find the employment periods of persons employed shorter time than DI.
ANSWER: ``{ [2/1/82 - 1/31/87], [4/1/87 - now]}''
CATEGORY: (None, Element, Union) / (Duration, Element, Computed) /(=, Constant)


=centercr @ []QUERY Q 3.1.6: When did someone get a raise more quickly than DI got her first raise?
ANSWER: ``06/01/82'' and ``09/01/86.''
CATEGORY: (None, Event, Derived) / (Duration, Interval, Computed) (Ordering, Interval, Computed) / (= ,Constant)


=centercr @ []QUERY Q 3.1.7: What was the longest period when no one was hired or left employment?
ANSWER: ``02/01/82–01/31/87''
CATEGORY: (None, Interval, Union) / (Duration, Interval, Computed) /


=centercr @ []QUERY Q 3.1.8: What was the longest period when no one received a raise?
ANSWER: ``09/01/86–now''
CATEGORY: (None, Interval, Union) / (Duration, Interval, Computed) /


=centercr @ []QUERY Q 3.1.9: When was the longest period when a department was without a manager?
ANSWER: ``Never.''
CATEGORY: (None, Interval, Union) / (Duration, Interval, Computed) /