System information

122 Chapter 10: Lesson 7: Validating Data to Enforce Business Rules

Reviewing the code

The following table describes the code used to verify whether the photo file exists:

Summary

As described in this lesson, ColdFusion offers a number of alternatives to validating data. If you

are familiar with standard page validation code, ColdFusion supports these development

approaches. However, ColdFusion form tags simplify data validation. In this lesson, you also

dynamically populated a list.

In the next lesson

Now that you are sure that your application can save valid data, in the next lesson, you will write

code to add trips to the database. Additionally, you will add logic to update existing trip data in

the Trips table.

Code Explanation

<cfset PhotoLocation =

"C:\CFusionMX7\wwwroot\cfdocs\

getting_started\photos\">

The cfset tag sets the value of the PhotoLocation path to

the appropriate directory.

Note: The code snippet shows one value for Windows

systems.

<cfset PhotoLocation =

PhotoLocation & FORM.photo>

The ColdFusion & operator in the cfset tag combines the

directory name with the name of the photo file entered in the

form.

<cfif not

FileExists(PhotoLocation)>

Trip Photo does not exist.

</cfoutput>

</cfif>

FileExists

checks to see if the file indicated by the

fileLocation variable exists at the specified disk location. If

it doesn’t, an error message appears.