Database Reference
In-Depth Information
When you define a container field, “maximum number of characters” changes to “maximum
number of kilobytes.” Set the value to, say, 1024, and FileMaker won't let you put any file
larger than a megabyte in the field.
Storage Options
It's time to get a little technical. In the Field Options dialog box, the Storage tab (see
Fig-
ure 6-8
) lets you control aspects of a field related to the nebulous concept of
storage
. Like a
highly organized attic, FileMaker both holds onto your information
and
makes it easy to take
out again. Lots of things determine how FileMaker compartmentalizes and maintains that in-
formation.
You can actually tell FileMaker to store only one value in a field that is the same in every re-
cord, no matter how many records you have, or to allow one field to hold more than one
value in each record. Strange, but true. Also, you get control over indexing, as described in
the next section.
WORKAROUND WORKSHOP: MINIMUM NUMBER OF CHARACTERS
For some strange reason, FileMaker doesn't provide a simple validation option to enforce a minim-
um number of characters in a field. If you need this sort of thing, then you have to dip into valida-
tion calculations. Luckily, the calculation to do it is really simple. Here's a validation calculation for
requiring at
least
five characters in the field:
Length(My Field) ≥ 5
To use this calculation, in the Validation tab, turn on the “Validated by calculation” option. In the
window that appears, type the calculation.
You have to change “My Field” to the name of your field. If you want a number other than 5, simply
change it in the calculation. When you're done, click OK.
If you want
more than
five characters, change ≥ to >. If you want
exactly
five characters (no more,
no less) then change ≥ to =. You don't need a lot of expertise for this calculation. If FileMaker gives
you an error and you can't figure it out, just click Cancel and then try again. (See
Chapter 9
for
much more on using calculations.)
Global Storage
“A field that uses global storage contains only one value that is shared across all records.” So
says the explanatory text in the dialog box, but what's that in English? When you use the
“Use global storage” option, everything you learned about tables goes out the window. A
global field
isn't like a column in the table at all. Rather, it's a single bit of storage that can
