Dataloader/MP Reference Manual

DataLoader/MP Components
DataLoader/MP Reference Manual—424148-003
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DataLoader/MP Structure
DataLoader/MP Structure
Internally, DataLoader/MP consists of three major components - the DataLoader/MP
main logic, user exits, and the DataLoader/MP library. Figure 2-1 shows the structure
of DataLoader/MP.
The main logic component performs the basic program control. It uses two other
components, the DataLoader/MP library and the user exits, to perform common
functions that might need to be extended by the user.
The user exits module contains the user exit procedures described in User Exit
Descriptions on page 5-4. The user exit procedures are called from specific points in
the main logic, allowing loading operations to be customized. The processing
flowcharts in Appendix B, Processing Flowcharts, describe places where the user exits
are called.
The DataLoader/MP library contains modules for common functions such as file
access, data conversion, and error handling, for use by both the main logic and user
exits. The library is described in DataLoader/MP Library
on page 5-14.
DataLoader/MP File System
To provide features important for loading that are not directly supplied by the Enscribe
file system, DataLoader/MP layers its own file system on top of the Guardian file
system. The DataLoader/MP file system is designed to support DataLoader/MP, so
some of the capabilities in the underlying Guardian file system are not used. For
example, DataLoader/MP processes files sequentially, so it does not use random I/O.
The DataLoader/MP file system includes these features for sequential file processing:
•
Concatenated files. DataLoader/MP enables you to point to data files that in turn
point to other data files. As a result, you can load from very large data files or to
Figure 2-1. Structure of DataLoader/MP
User Exits
Library
VST001
DataLoader/MP Main Logic