User Guide

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CHAPTER 8
Lesson 4: Validating Data to Enforce
Business Rules
In this lesson, you will enhance the Compass Travel Trip Maintenance application. The exercises
in this lesson will guide you through the steps of enhancing the application to provide a page for
the trip coordinator to add new trip offerings and update existing trips. Further, you will add
logic to validate that data entered against Compass Travel business rules.
This lesson explains how to do the following tasks:
• Create a data entry form to capture user input information.
• Develop an action page to process posted form variables.
• Validate captured data in three ways.
ColdFusion tags and functions introduced in this lesson
The following table identifies the ColdFusion tags and functions that you use in this lesson to
enhance the ColdFusion application:
Element Type Description
cfform
Tag Builds a form with CFML custom control tags that provide more
functionality than standard HTML form input elements.
cfinput
Tag Use inside cfform to place radio buttons, checkboxes, or text boxes.
Provides input validation for the specified control type.
cfselect
Tag Used inside cfform, cfselect lets you construct a drop-down list box form
control. You can populate the drop-down list box from a query, or use the
option tag. You further use
option elements to populate lists. The syntax for
the option tag is the same as for its HTML counterpart.
FileExists
Function Returns True if the file specified in the argument exists; otherwise it returns
False.