You can override the system default values with user-defined default values for supported input, pass-through, and output ports within a connected transformation.
Use the following rules and guidelines to override the system default values for ports:
Input ports.
You can enter user-defined default values for input ports if you do not want the Integration Service to treat null values as NULL. If NULL is passed to the input port, the Integration Service replaces NULL with the default value.
Output ports.
You can enter user-defined default values for output ports if you do not want the Integration Service to skip the row or if you want the Integration Service to write a specific message with the skipped row to the log. If you define a default value in the output port, the Integration Service replaces the row with the default value when the output port has a transformation error.
Pass-through ports.
You can enter user-defined default values for pass-through ports if you do not want the Integration Service to treat null values as NULL. You cannot enter user-defined default values for output transformation errors in a pass-through port.
The Integration Service ignores user-defined default values for unconnected transformations. For example, if you call a Lookup or Stored Procedure transformation through an expression, the Integration Service ignores any user-defined default value and it applies the system default value.
Use the following options to enter user-defined default values:
Constant value.
Use any constant (numeric or text), including NULL.
Constant expression.
You can include a transformation function with constant parameters.
ERROR.
Generate a transformation error. Write the row and a message in the mapping log or row error log.