Studierende stehen vor dem LC und blicken lächelnd einer Kollegin mit einer Mappe in der Hand nach.

Exercise No. 45: Pizza Service (apa)

As the re­sult of DFM Case "pizza ser­vice" this cube stores data about or­de­ring a pizza at a pizza ser­vice.

We have five di­men­si­ons with the fol­lo­wing hier­ar­chi­cal struc­tu­re:

Table A.E.26.1 - pizza ser­vice

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

1) "a daily re­port for each com­bi­na­ti­on of cook and em­ployee in­de­pen­dent of all other di­men­si­ons"

2) "a weekly re­port on cus­to­mer groups and the branch of pizza ser­vice in­de­pen­dent of all other di­men­si­ons"

3) "a weekly re­port for each com­bi­na­ti­on of cus­to­mer group and city district, ir­re­spec­ti­ve of the other di­men­si­ons"

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

So­lu­ti­on

Fi­gu­re A.E.26.1 - The re­sul­ting APA with the red­un­dan­cy free-​set high­ligh­ted

Size of the redundancy-​free set (in­clu­ding the base cube): 216

Re­qui­red cubes, the ma­te­ria­liza­ti­on de­cis­i­on and de­ri­va­ti­ves

The blue area re­p­res­ents the end-​user re­qui­re­ment 1 ("a daily re­port for each com­bi­na­ti­on of cook and em­ployee in­de­pen­dent of all other di­men­si­ons"), re­qui­re­ment 2 ("a weekly re­port on cus­to­mer groups and the branch of pizza ser­vice in­de­pen­dent of all other di­men­si­ons") and re­qui­re­ment 3 ("a weekly re­port for each com­bi­na­ti­on of cus­to­mer group and city district, ir­re­spec­ti­ve of the other di­men­si­ons").

Ma­te­ria­li­zing cube v = (CO_co,B_*,C_*,T_d,E_em) (dark blue cell "C_*", re­p­re­sen­ting end-​user re­qui­re­ment 1), cube w = (CO_*,B_bp,C_gr,T_w,E_*) (dark green cell "T_w", re­p­re­sen­ting end-​user re­qui­re­ment 2) and cube x = (CO_*,B_*, C_gr,T_w,E_cd) (red cell "E_cd", re­p­re­sen­ting end-​user re­qui­re­ment 3) offer us the fol­lo­wing sets of de­ri­va­ti­ves.

Fi­gu­re A.E.26.2 - De­ri­va­ti­ves of cube v = (CO_co,B_*,C_*,T_d,E_em)

Fi­gu­re A.E.26.3 - De­ri­va­ti­ves of cube w = (CO_*,B_bp,C_gr,T_w,E_*)

Fi­gu­re A.E.26.4 - De­ri­va­ti­ves of cube x = (CO_*,B_*, C_gr,T_w,E_cd)

Fi­gu­res A.E.26.2, A.E.26.3 and A.E.26.4 show that no end-​user re­qui­re­ment is co­ver­ed by the de­ri­va­ti­ves of ano­ther. To meet all end-​user re­qui­re­ments we will have to ma­te­ria­li­ze all three cubes, v, w and x.

This ex­er­ci­se is part of a case study: dfm - apa - log

Ex­er­ci­s­es List