Databases Reference
In-Depth Information
In the
Output
pane of the analytic view, you'll see a node named
Calculated Attributes
, as we
can see here:
Right-click on the
Calculated Attributes
node, then select
New
from the menu. You'll see the
Calculated Attribute
dialog window, which asks for a name and a description for the attribute
(we'll use
NEXT_YEAR
as both name and description). The data type for the calculated attribute
is
VARCHAR
with a length of
4
—this is the same type as the original
ORDER_YEAR
field.
Next, we need to enter the formula used to calculate the attribute. If you've used formulas in
Excel, then this will seem familiar; it works the same way.
Basically, what we need to do is to take the value of the
ORDER_YEAR
column, and add
1
.
However, we can't work on the
ORDER_YEAR
column directly; as we've just seen, its data type
is
VARCHAR
, which is a string of characters.
In order to do mathematical calculations on the value in the
ORDER_YEAR
column, we must
first obtain a numeric representation of the value. Next, we'll add
1
to this value, and then
retransform the result back into a string.
This can be summarized in the following points:
Ê
Obtain a numeric representation of the contents of the
ORDER_YEAR
column
Ê
Add
1
Ê
Transform the result of the calculation back into a string representation
