Variable Prefixing

Because variables can differ in scope and can overlap, you need to be aware that sometimes a variety of variables will be available to a ColdFusion application page and some may variables may share the same name.

To ensure ColdFusion evaluates the appropriate variable, reference a variable by prefixing a variable name with its type. The table below describes each variable by its prefix.


Variable Type	Prefix	Reference Syntax
Local	Variables.	Variables.VariableName
Query	*QueryName.	QueryName.VariableName
Form	Form.	Form.VariableName
URL	URL.	URL.VariableName
Cookie	Cookie.	Cookie.VariableName
CGI.	CGI.	CGI.VariableName
Application	Application.	Application.VariableName

* Where QueryName is the NAME attribute that you assigned in the CFQUERY tag. You will learn more about querying a database in the next chapter.

Variable prefixing example

The code below outputs the current value of the ProductName local variable:

<CFOUTPUT>
    #Variables.ProductName#
</CFOUTPUT>

Prefix variables with the variable type. (This is optional for local variables.)
Surround the variable reference with pound signs (#) so that ColdFusion knows to replace the variable name with the variable value.

The code below outputs the current value of the ProductName form variable:

<CFOUTPUT>
    #Form.ProductName#
</CFOUTPUT>

The code below outputs the current value of the ProductName query results:

<CFOUTPUT QUERY="ProductName" DATASOURCE="HRApp">
    #ProductName.ProductName#
</CFOUTPUT>

Note:

Allaire recommends that you prefix any variables other than local when referencing them.