The Parameter Variables Section

When defining values for fields in certain control tables in the registry, you may reference substitution variables that point to the <ParameterVariables> section of the installation files. Substitution variables provide for dynamic substitution of values based on parameters provided at server startup.

To specify a substitution parameter in a string value you enter the name of the substitution parameter enclosed with @.

For example if you have a field in the XAI control tables that should contain the URL for the XAI HTTP servlet, you could enter the value in the following way: http://@HOST@:@PORT@/xaiserver.

In the parameters section, define the appropriate values for these parameters, for example:

	<ParameterVariables>
	<ParameterVariable name="HOST" value="localhost" />
	<ParameterVariable name="PORT" value="8001" />
	</ParameterVariables>

At run time, the system builds the URL as http://localhost:8001/xaiserver.

Every substitution parameter is defined using an <ParameterVariable> element with the following attributes:

Attribute Name	Description
Name	The name of the substitution parameter
Value	The value to replace an occurrence of the substitution parameter in an XAI control table field

Note: Substitution parameters can only be used for string fields, and not for fields that are foreign keys to other objects.