Describe the four common OLAP operations for querying data. Provide an example of each operation using the OLAP cube in Figure 33.2.
Common OLAP operations include:
(1) Roll-up, (2) drill-down, (3) slice and dice, and (4) pivoting.
Roll-up performs aggregations on the data by moving up the dimensional hierarchy or by dimensional
reduction e.g. 3-D to 2-D.
For example, {country, media and time} analysis of media streaming to {country, media} analysis of
streaming.
For example, analysis of weekly media streaming to analysis of monthly streaming.
Drill-down is the reverse of roll-up and involves revealing the detailed data that forms the aggregated
data. Drill-down can be performed by moving down the dimensional hierarchy or by dimensional
introduction e.g. 2-D to 3-D.
For example, {country, media} analysis of media streaming to {country, media and time} analysis of
streaming.
For example, analysis of monthly of media streaming to analysis of weekly streaming.
Slice and dice - ability to look at data from different viewpoints. The slice operation performs a
selection on one dimension of the data whereas dice uses two or more dimensions.
For example, a slice is analysis of media streaming according to {time = ‘2014’} OR {media = ‘film’}
OR {location = ‘London’}
For example, a dice is analysis of media streaming according to {time = ‘2014’} and {media = ‘film’}
OR {time = ‘2014’} and {media = ‘film’} and {location = ‘London’}
Pivot - ability to rotate the data to provide an alternative view of the same data.
For example, analysis of media streaming using the location (city) as x-axis against time (year) as the
y-axis can be rotated so that time (year) is the x-axis against location (city) is the y-axis.
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Match each of the following ethical systems with one of its basic tenets:
I. relativism II. divine command theory III. utilitarianism IV. virtue ethics V. deontology A. actions are judged solely by consequences B. morals are internal C. God is all-knowing and sets moral standards D. morals should apply to everyone equally E. no universal moral truth
The scope of a variable or constant is ____ to the method or program in which it is declared.
A. global B. local C. public D. private
You can add more components by downloading them from Web resources such as Flash ____, which is an Adobe Web site with resources for Flash developers.
A. Matrix B. Portal C. Exchange D. Mash
One assertion that locality is based on is that as a function of time, the probability that a given unit of memory is referenced tends to change __________.
A. slowly B. rapidly C. dramatically D. not at all