For example, configure a filter condition in the Filter transformation. Choose the ports and the parameters to include in the condition. Select the system parameters or the user-defined parameters to include in the filter condition.

The following image shows a Filter condition that includes the Employee port and the Employee_Filter parameter:

You can use parameters in expressions in the same arguments that accept port names as arguments. You cannot use a parameter to replace a constant argument in an expression.

For example, consider the TO_DECIMAL expression that converts a string to a decimal value:

TO_DECIMAL( value [, scale] )

The scale argument must be a constant value in the expression.

The following valid expression contains a constant argument for scale:

TO_DECIMAL( Input_Port,10 )

The following expression is not valid because it contains a user-defined parameter for the scale argument :

TO_DECIMAL( Input_Port,$Scale_Param )

A parameter cannot contain another parameter. For example, if you configure Parameter1 and Parameter2 in a transformation, you cannot set the default value of Parameter1 to $Parameter2. If you nest the parameters, the mapping fails with a validation error at runtime.