Database Reference
In-Depth Information
UP TO SPEED: EVALUATING CALCULATIONS: NOW OR LATER
When you use a calculation, you're asking FileMaker to do something with your fields, constants,
and operators and come up with a result. In technical lingo, FileMaker
evaluates
the calculation.
When
the evaluation takes place depends on
where
in your database FileMaker encounters the calcu-
lation. Sometimes FileMaker evaluates it right away, as when you're calculating an Extended Price.
As soon as you type either a price or a quantity, FileMaker tries to multiply the value. But since one
of the fields is empty, the Extended Price calculation has a result of zero. When you provide the
second value, FileMaker immediately does the math and shows you your result:
▪ If you create a new calculation field after you already have data in your database, then
FileMaker updates the data for all records as soon as you close the Manage Database dialog
box. You may see a progress bar if you have a lot of records.
▪ When you run the Records→Replace Field Contents command, FileMaker evaluates the calcu-
lation you specify once for every record as soon as you click OK. As above, this may take a
couple of seconds, but it's happening just as soon as FileMaker can plow through your found
set.
▪ Validation calculations evaluate whenever you change the field or exit the record (you get to de-
cide). See
Validate Data Entry with a Calculation
for more on these.
▪ Calculations used in scripts are evaluated when the script runs.
NOTE
Sometimes people call a Boolean value “True or False” or “One or Zero” instead. Which term you
use doesn't matter much if you just remember that there's a yes-like value and a no-like value.
Using Fields in Calculations
It's very common to reference fields in calculations. For example, let's say a field has this
calculation:
First Name & " " & Last Name
NOTE
See
Adding a Field Control Style and a Value List
to learn how to use this calculation to show data
from more than one field in a value list.
