Table A.E.57.1 - Memorial Hospital

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

1) "a roll-up of the time dimension starting at weeks for each department independent of all other dimensions"

2) "a monthly report for each ward"

3) "a complete drill-down by the time dimension down to day for each combination of patient and nurse"

Select the corresponding cells in the APA and choose a cube to materialize, then highlight the derivatives of this cube.

Figure A.E.57.1 - The resulting APA with the redundancy free-set highlighted

Size of the redundancy-free set (including the base cube): 128

Required cubes, the materialization decision and derivatives

The blue area represents the end-user requirement 1 ("a roll-up of the time dimension starting at weeks for each department independent of all other dimensions"), the end-user requirement 2 ("a monthly report for each ward") and the end-user requirement 3 ("a complete drill-down by the time dimension down to day for each combination of patient and nurse").

Materializing cube v = (N_*, P_*, D_de, T_w) (dark blue cell "T_w", representing end-user requirement 1), cube w = (N_*, P_wa, D_*, T_m) (dark green cell "T_m", representing end-user requirement 2) and cube x = (N_nu, P_pa, D_*, T_d) (red cell "D_*", representing end-user requirement 3) offer us the following sets of derivatives.

Figure A.E.57.2 - Derivatives of cube v = (N_*, P_*, D_de, T_w)

Figure A.E.57.3 - Derivatives of cube w = (N_*, P_wa, D_*, T_m)

Figure A.E.57.4 - Derivatives of cube x = (N_nu, P_pa, D_*, T_d)

Figures A.E.57.2 to A.E.57.4 show that end-user requirement 2 is covered by the derivatives of the vector x (end-user requirement 3). To meet all end-user requirements we will only have to materialize two cubes, v and x.