Work
with Categories, Levels, and Nodes
The top
node that has appeared in the new PivotDiagram
contains a summary total, based
upon a default measure selected from the Adventure Works cube (in this
case, the default measure is Internet Sales Amount). In effect, the top
node value represents an “All” amount; were we using the PivotDiagram
as a reporting mechanism (as we intimated earlier that many will do), we
would be able to present a visual “drilldown” of a given value (alone or in
combination with other values) by creating underlying levels and categories
(referred to in the Analysis Services arena as “members”),
based upon our dimensional hierarchy. (We will accomplish the same
effect in our practice example, too, for a slightly different reason.)
When we use a PivotDiagram as a design and documentation tool, we want to concentrate more on
employing it to present the physical structure of various cube objects; the
addition of measures is simple enough, and the use of the wizard has positioned
us to get a glance of how the PivotDiagram presents values in general, should
we need to do that for another reason at another time. Anytime we do not need
to analyze or present measure data, we can modify the PivotDiagram
to focus upon structure without measure values. For purposes of this
session, we will modify the default measure, substituting a count value
in its place that happens to serve as a quick visual check of member
completeness. Before we do this, we will save our rudimentary PivotDiagram as
it stands.
1.
Select File
-> Save As ... from the main menu.
2.
Navigate to a
location where it is convenient to save the new Visio file.
3.
Within the Save
As dialog that appears, type the following name into the File name
box:
DBJ_PivotDiagram_Initial_Foundation.vsd
The relevant portion of
the Save As dialog appears as shown in Illustration 11.
Illustration 11: Saving
the Initial PivotDiagram File ...
4.
Click Save to
save the file and close the dialog.
Now we can make a few
alterations to fit our immediate goals of design support and documentation.
First, we will change the measure value that appears by default, substituting
instead a measure that will coincidentally help to support easy verification of
completeness within the PivotDiagram we are creating for our practice session.
5.
In the PivotDiagram
task pane, within the Add Total selection list, uncheck the currently
selected measure, Internet Sales Amount.
We note that the PivotDiagram
updates, refreshing itself to reflect our removal of the default measure.
6.
Within the Add
Total selection list, once again, place a checkmark alongside the Customer
Count measure to select it.
The PivotDiagram updates
once again, and appears as depicted in Illustration 12.
Illustration 12: The
PivotDiagram Updates for the Newly Selected Measure ...
We will see that the Customer
Count “carries downward,” as we create lower levels, permitting us to
visually verify that rollup is occurring as expected.
Next, we will add a category
to the diagram. In this case, the category we add, Customer
Geography, will become a level under the top node. Categories
are typically non-numeric (but certainly not always), and, when acting as levels,
can be summarized upon.
7.
Click the top node on the canvas to select it.
We see an outline form
around the shape, indicating it selection with regard to the actions we are
about to take.
8.
In the PivotDiagram
task pane, within the Add Category selection list, click Customer:
Country, as shown in Illustration 13.
Illustration 13: Adding
a Category to the PivotDiagram ...
Customer Geography is a hierarchy within the
Customer dimension of the Adventure Works cube. Customer:
Country is a level within the Customer Geography hierarchy. Visio
exposes it as a category selection, and from the task pane, we can
select and use it as a level within the PivotDiagram.
The PivotDiagram updates
once again, and reflects the addition of the Country members, as
depicted in Illustration 14.
Illustration 14: The
PivotDiagram Updates for the Newly Selected Measure ...
We also note the appearance
of the Country level within the PivotDiagram. It is at this
point in the object that we will perform our next step, and filter our
newly added level.
9.
Right-click
the Country level, appearing between the top node and the newly
added Country sub nodes.
10.
Select Configure
Level ... from the context menu that appears, as shown in Illustration 15.
Illustration 15: Configuring
the New Level ...
The Configure Level dialog
opens.
11.
Within the Filter
section of the dialog, within the selector containing the placeholder expression
“(Select Operation),” just under, and to the right of, the label Show
data where: Country, select equals from among the available choices.
12.
Type the
following into the box to the immediate right of the selector now containing “equals:”
United States
The Configure Level dialog
appears, with our additions, as depicted in Illustration 16.
Illustration 16: Building
a Filter Expression for the Level ...
13.
Click OK
to accept the new filter definition, and to dismiss the Configure Level dialog.
Note: Anytime we are working within Visio,
and the import of external data will be brought about through an action
we have initiated, a Microsoft Office Visio Security Notice dialog may
appear, containing a warning message. The warning simply reminds us that
external data will be imported as a part of refreshment, and asks that we
indicate whether this is acceptable. We can turn off the message by clicking
the checkbox that appears, as desired.
14.
Click OK to
close the Microsoft Office Visio Security Notice dialog (an example of
which is shown in Illustration 17), as appropriate.
Illustration 17: Click
OK to Dismiss the Security Notice
The PivotDiagram updates
as usual, and reflects the effects of the filter upon the members of the
recently added Country level, as depicted in Illustration 18.
Illustration 18: The
PivotDiagram Updates for the Newly Added Filter ...
As we have seen, we can
employ filters to choose which nodes appear in a level that we
add to the PivotDiagram. The PivotDiagram affords us the
capability to narrow our presentation to specific nodes of interest, by
allowing us to conceal nodes that we do not wish to see for given purposes.
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