Siebel Order Management Infrastructure Guide > PSP Engine > Components of the PSP Engine >
A PSP procedure is any workflow that uses methods from the Row Set Transformation Toolkit business service. These methods of the Row Set Transformation Toolkit business service are called PSP transforms. A transform, such as the Simple Look-Up method, processes an input row set. There are a number of transforms that process input row sets in different ways. For example, the Simple Look-Up transform uses a simple search expression to look up each input row in a business component, while the Split transform takes an input row set, evaluates a condition for each of its rows, then splits the input row set into two output row sets.
NOTE: In addition to invoking Row Set Transformation Toolkit business service methods, a PSP procedure can invoke methods from custom business services.
Each step in a PSP procedure is a parameterized call to a transform method. A PSP procedure can call another PSP procedure as a subprocess, to provide for modularization of logic.
The Siebel Business Process Designer interface is used to create both the PSP procedure and the controller workflow that invokes it. Like any workflow process, a PSP procedure can make use of any standard Siebel Workflow feature.
Figure 16 shows an example of a PSP procedure used in pricing. Each step is a parameterized call to a method in the Row Set Transformation Toolkit.
Notice that one of the steps splits the input row set into multiple temporary subsets. Later steps perform logic on these subsets. The last step merges these subsets, so they form a single row set again.
Figure 16. Example of a PSP Procedure