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address (cities) New York 1560 440
Chicago

Toronto
Vancouver 395
<Vancouver,
Q1 605 825 14 400 Q1, security>
time (quarters) Q2

Q3

Q4
computer security
home phone
entertainment
item (types)
(a)
Drill-down Roll-up
on time data for Q1 on address

address (cities) New York address (countries) USA 2000
Chicago
Canada
1000
Toronto
Vancouver 150 Q1
Q2
Jan
time (months) Feb 100 time (quarters) Q3

Q4
March
150
computer security computer security
home phone home phone
entertainment entertainment
item (types) item (types)
(b)

Figure 1.7 A multidimensional data cube, commonly used for data warehousing, (a) showing summa-
rized data for AllElectronics and (b) showing summarized data resulting from drill-down and
roll-up operations on the cube in (a). For improved readability, only some of the cube cell
values are shown.