Programming instructions

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.