In the previous 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.
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.