Using Functions and Transforms

The Designer provides both internal functions and transforms to act on COBOL data items. In determining when to use an internal function and when to use a transform, consider the following points:

• Internal functions are used to synthesize a COBOL data item using the value or values of one or more other COBOL data items within the same FD. These synthesized COBOL data items may be used as any other COBOL data item. Transforms are used to "transform", or convert, existing COBOL data items.
• An internal function can operate on more than one COBOL data item. A transform can operate only on a single COBOL data item.
• An internal function must be applied to the COBOL data item in the FD. A transform can be applied to the COBOL data item in the FD or at the column level. If the transform is applied at the FD level, all the columns that use that COBOL data item will use the transformed item. If the transform is applied at the column level, only those columns with the transforms will be affected. In the case of a data item that will always be transformed, such as a date data item, it is better to apply the transform at the FD level. If the data item sometimes needs to be transformed, and other times not, it is better to apply the transform at the column level.
• An internal function may have another function as an argument.