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DEVELOPING
COLDFUSION 9 APPLICATIONS
Requesting and Presenting Information
Las
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d 8/5/2010
On the action page, the form variables are in the Form scope, prefix them with “Form.” to explicitly tell ColdFusion
that you are referring to a form variable. For example, the following code references the LastName form variable for
output on an action page:
<cfoutput>
#Form.LastName#
</cfoutput>
The Form scope also contains a list variable called
Form.fieldnames
. It contains a list of all form variables submitted
to the action page. If no form variables are passed to the action page, ColdFusion does not create the
Form.fieldnames
list.
Using form data to generate SQL statements
As described in previous chapters, you can retrieve a record for every employee in a database table by composing a
query like the following:
<cfquery name="GetEmployees" datasource="cfdocexamples">
SELECTFirstName, LastName, Contract
FROM Employee
</cfquery>
When you want to return information about employees that matches user search criteria, you use the SQL WHERE
clause with a SQL SELECT statement. When the WHERE clause is processed, it filters the query data based on the
results of the comparison.
For example, to return employee data for only employees with the last name of Smith, you build a query that looks like
the following:
<cfquery name="GetEmployees" datasource="cfdocexamples">
SELECT FirstName, LastName, Contract
FROM Employee
WHERE LastName = 'Smith'
</cfquery>
However, instead of placing the LastName directly in the SQL WHERE clause, you can use the text that the user
entered in the form for comparison:
<cfquery name="GetEmployees" datasource="cfdocexamples">
SELECT FirstName, LastName, Salary
FROM Employee
WHERE LastName=<cfqueryparam value="#Form.LastName#"
CFSQLType="CF_SQL_VARCHAR">
</cfquery>
For security, this example encapsulates the form variable within the
cfqueryparam
tag to ensure that the user passed
a valid string value for the LastName. For more information on using the
cfqueryparam
tag with queries and on
dynamic SQL, see “
Accessing and Retrieving Data
” on page 410.
Creating action pages
Use the following procedure to create an action page for the formpage.cfm page that you created in the previous
example.
Create an action page for the form
1
Create a ColdFusion page with the following content: