Table A.E.25.1 - writing tests

Please build the Aggregation Path Array and assume the following end-user requirements:

1) "a report for each semester on student type, independent of the professor and assistant"

2) "an annual report for each combination of assistant and student, irrespective of the professor"

Select the corresponding cells in the APA and choose the cubes to materialize, then highlight the derivatives of those cubes.

Figure A.E.25.1 - The resulting APA with the redundancy free-set highlighted

Size of the redundancy-free set (including the base cube): 36

Required cubes, the materialization decision and derivatives

The blue area represents the end-user requirement 1 ( "a report for each semester on student type, independent of the professor and assistant") and requirement 2 ("an annual report for each combination of assistant and student, irrespective of the professor").

Materializing cube v = (P_*,A_*,S_ty,T_s) (dark blue cell "S_ty", representing end-user requirement 1) and cube w = (P_*,A_as,S_st, T_y) (dark green cell "T_y", representing end-user requirement 2) offer us the following sets of derivatives.

Figure A.E.25.2 - Derivatives of cube v = (P_*,A_*,S_ty,T_s)

Figure A.E.25.3 - Derivatives of cube w = (P_*,A_as,S_st, T_y)

Figures A.E.25.2 and A.E.25.3 show that end-user requirement 2 is not covered by the derivatives of v. To meet all end-user requirements we will have to materialize both cubes, v and w.