Custom Transformation

Custom transformations operate in conjunction with procedures you create outside of the Designer interface to extend PowerCenter functionality. You can create a Custom transformation and bind it to a procedure that you develop using the Custom transformation functions. Use the Custom transformation to create transformation applications, such as sorting and aggregation, which require all input rows to be processed before outputting any output rows. To support this process, the input and
output functions occur separately in Custom transformations compared to External Procedure transformations.

The Integration Service passes the input data to the procedure using an input function. The output function is a separate function that you must enter in the procedure code to pass output data to the Integration Service. In contrast, in the External Procedure transformation, an external procedure function does both input and output, and its parameters consist of all the ports of the transformation