Database Reference
In-Depth Information
Chapter 4. Adding Power to Your
Database
In the last chapter, you created a custom database for storing lease documents. You learned
how to create fields of the appropriate type to store your data and then you customized two
layouts—one for viewing the data as a form and a second for viewing the data in a list.
If you never went any further than that, you'd still have a database that tracks documents.
But now that your business is more efficient, it's time to teach the database some new tricks.
You're already storing the signing date and lease duration data for each lease. In this chapter,
you'll create a field that lets you know when each lease is ending. Then you'll create a new
table and all the supporting mechanisms for recording monthly payments.
Creating a Simple Calculation
On
Managing Field Types
, you learned about field types as you created them. You chose a
field type based on the kind of data you wanted to enter into each field. But calculation fields
can create data under their own power. For instance, your database already stores monthly
Rental Fee and Lease Duration data. If you wanted to figure out the value of that lease over
its life, you could punch the numbers into a calculator and then manually enter the result into
your database. But a calculation field calculates and enters data automatically and can even
update if the data in either field changes. All you have to do is write a formula that tells the
calculation field how to get the answer you want.
NOTE
This tutorial picks up where
Chapter 3
left off. If you didn't complete those tutorials, or you want to
start with a clean file that's already got some data in it, download the samples from this topic's
Missing CD page at
www.missingmanuals.com/cds/fmp13mm
.
Creating Fields with Manage→Database
In the last chapter, you created fields with the Field Picker (
Creating Fields
)
. But for creating
fields with more control, call up the Manage Database window (
Figure 4-1
)
. That's how
you'll create your first calculation field:
