10.
Execute the
query by clicking the Run Query button in the toolbar.
We
receive a message box, as shown in Illustration 5, stating that the Sample
Application is unable to display the opened cellset - essentially because
the dataset is empty.
Illustration 5: Message - Empty Cellset
The
message box closes, and we are confronted with the empty cellset (perhaps only
briefly), as expressed by the Sample Application (See Illustration 6.)
Illustration 6: Empty Cellset as Expressed by the Sample
Application
12.
Re-save the
file as MDX19-3.
And so
we see that a numerical expression less than 1 within the Head()
function elicits the return of an empty cellset. Now, let's examine one
last provision for oddball numeric input: what happens when we input a number that
is higher than the total number of tuples in the specified set?
13.
Within the
query we have saved as MDX19-3, replace the top comment line of the
query with the following:
-- MDX019-4, Use of Head() Function - Numeric Expression > Total Tuples in Set
14.
Save the query
as MDX19-4.
15.
Replace the
numeral -1 with the numeral 6, in the following line of the existing
query:
{Head([Time].[1998].Children, -1)} ON COLUMNS,The
Query pane
appears as shown in Illustration 7, with the inserted coding circled in
red.
Illustration 7: The Query with Numerical Expression Larger
than Set
16.
Execute the
query by clicking the Run Query button in the toolbar.
The
Results pane is
populated, and the dataset shown in Illustration 8 appears.
Illustration 8: Results of the Modified Numeric Expression
We see
that, even though the numerical expression that we input exceeds the number of
tuples in the specified set (only four Quarters exist in any single Year),
Head() returns the Full Set only.
17.
Re-save the
file as MDX19-4.
We
have explored examples of the behavior of the Head() function under
various scenarios of numeric expression input for a specified set. We
saw that the function manages potential input by providing a "default"
numeric expression to drive its behavior, with regard to the results it produces.
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