Using User-Defined Functions

To include a user-defined function in an expression

  1. Develop your own function using Visual Studio or any other IDE.

    Note: It is recommended to provide a function name that is not the same as any built-in system function or existing user-defined function. To manage functions with the same name, the assembly name is prefixed to the user-defined function name. For example, the following are two assemblies within Data Exchange, both containing the same function named "StringConcat":

    • Asm1.dll

    • Asm2.dll

    While importing the functions into DDW, the functions are prefixed as follows:

    • Asm1.StringConcat

    • Asm2.StringConcat

  2. Copy the generated binary file to the following specified installation folders of Data Exchange.

    Note: Following are the paths to place the generated binary file, if you installed Data Exchange with the default settings:

    • C:\Program Files\Unisys\Data Exchange\Development Workbench\Functions\External

    • C:\Program Files\Unisys\Data Exchange\Runtime Service\Functions\External

    • C:\Program Files\Unisys\Data Exchange\Runtime Administration\Administrative Service\Functions\External

  3. To enable the functions you defined, close and re-launch DDW and restart the Runtime Service and the Administrative Service.

    You can view the functions in the Expression window under User-Defined Functions in DDW.

    An instance of the user-defined function is created when the Runtime Service starts and is not discarded until the service terminates.

Refer to Appendix A. Sample Implementation of a User-Defined Function for a sample example on how to create a user-defined function using Visual Studio.