Function mappings

Federation component supplies default mappings between existing data source functions and counterpart functions. For most data sources, the default function mappings are in the wrappers. The default function mappings to functions are in the DRDA wrapper. The default function mappings to Sybase functions are in the CTLIB wrapper, and so forth.

For relational data sources, you can create a function mapping when you want to use a data source function that the federated server does not recognize. The mapping that you create is between the data source function and a counterpart function at the federated database. Function mappings are typically used when a new built-in function or a new user-defined function become available at the data source. Function mappings are also used when a counterpart function does not exist. In this case, you must also create a function template.