Function strings for functions can be automatically generated for function-string classes that come with Replication Server. Function strings must be customized for any function-string class that the user creates that does not inherit its functions strings from one of the provided classes. To customize a function string, you modify an existing function string with data-server-specific commands or by invoking a remote procedure call (RPC). A customized function string can also contain function string variables that represent the values of columns, procedure parameters, system-defined information, and user-defined variables. Replication Server replaces the variables with actual values before sending function strings to the data server.
See Chapter 2, “Customizing Database Operations” in the Replication Server Administration Guide Volume 2 for details.