I have a DT called LoadValues, it has a parameter called code with default value 1234 and this data transform sets a property .code to Param.code value. When I call this DT from an activity and don't provide parameter (or don't pass parameters page) I would expect that the property value is set to the default value of the parameter, but it's not.
Never mind Rachit, I thought that default values does something else unfortunately.
Optional. You can enter a literal constant value that appears as the default parameter value when the system presents a parameter prompt form to a user invoking this data transform. For example, when this data transform is used in an Apply Data Transform action in another data transform, the user can bring up a window in which to specify the input parameter values. That window displays these default values.