Macromedia colfusion mx 7-getting started building coldfusion mx applications User Manual

Exercise 4: Providing server-side validation

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Exercise 4: Providing server-side validation

In this exercise, you will learn about the following tasks:

•

Creating a local variable to indicate whether data entered in the form conforms to the 
Compass Travel business rules

•

Ensuring that a value was entered

•

Evaluating check box and radio button variables

•

Adding validation for all Compass Travel business rules

Creating a local variable

The purpose of the tripeditaction.cfm action page is to update the Compass Travel database, so it 
is important to make certain that any values entered conform to all the business rules before 
modifying the database. Failure of any one of the rules prevents modification of the database. 

One approach to ensuring that the action page considers each business rule is to create a local 
variable with a 

cfset

 tag within the action page that tests whether any of the business rules failed. 

The 

cfset

 tag lets you manipulate the value of a variable. For example, the following pseudocode 

initializes a variable to a specific value and checks the value using the 

cfif

 statement:

<cfset isOk = "Yes">
if rule 1 fails then
<cfset isOK = "No"
...
if Rule n fails then
<cfset isOk = "No">
...
<cfif isOk = "Yes">

update the database

</cfif>

In this example, the 

cfset

 tag initializes the local variable 

isOk

 to Yes

.

 If any rule fails, the 

variable 

isOK

 is set to No. The code then tests if 

isOk

 equals Yes, before executing the SQL insert 

logic. 

To create the local variable:

1.

Open the tripeditaction.cfm file in an editor.

2.

Add the following code at the top of the file:

<cfset isOk = "Yes">

3.

Modify the file by adding the following highlighted code:

<h1>Trip Added</h1>
<!--- Database insert logic goes here. --->
<cfoutput>

You have added #Form.TripName# to the trips database.

</cfoutput>

4.

Save the file.