Expression Transformation Ports
An Expression transformation has different port types that you can reference when you define expressions.
An Expression transformation has the following port types:
- Input
- Receives data from upstream transformations. If the Expression transformation does not change the port value, you can define a pass-through port instead of an input port.
- Output
- Contains the return value of the expression. You enter the expression as a configuration option for the output port. You can also configure a default value for each port.
- Pass-Through
- Define a pass-through port to pass the data through the transformation without changing the value. You can reference a pass-through port in a calculation, but you cannot change the data value in the pass-through port.
- Variable
- Temporarily stores data to use in expressions. You can store data across multiple rows. You can define an expression to return a value to a variable port.
- Dynamic Port
- Receives or returns ports in a dynamic mapping. A dynamic port can receive one or more columns from an upstream transformation and create a generated port for each column. A dynamic output port can return one or more generated ports. You can define input rules to determine which columns a dynamic port receives. A dynamic output port can contain an expression that generates multiple output ports.
- Generated Port
- A port that represents a single column within a dynamic port. The generated ports in the Expression transformation might change based on the columns that the Expression transformation receives from an upstream transformation.