DIFROM

Order Entry and DIFROM

DIFROM for VA FileMan versions 18 and later has been customized to support Order Entry. Order Entry inits must export records from the PROTOCOL file (#101). This file contains pointers back to itself, similar to the OPTION file (#19). Since DIFROM does not currently resolve these pointers, a joint effort was made by Order Entry and FileMan developers to support Order Entry inits that correctly install the protocols. (See Order Entry documentation for details.)

Basically, the process involves the creation of a second set of routines, similar to init routines, to export the Order Entry protocols and to resolve the pointers in the PROTOCOL file. An Order Entry routine, ORVOM, is run to create these routines. The resulting routines are named nmspONI*, the ONIT routines. These routine are run at the target site after the init routines to install the protocols.

The following considerations pertain to the creation of Order Entry inits:

• Like regular inits, Order Entry inits can be created either based on an entry in the PACKAGE file (#9.4) or on the fly.
  
  
• Order Entry's file Order Parameters contains a multiple called PACKAGE PARAMETERS. This multiple controls the export and installation of entries from the PROTOCOL file. Thus, it is used like the PACKAGE file. To export entries from the PROTOCOL file in a sophisticated way, use the PACKAGE PARAMETERS instead of building the export on the fly.
  
  If the developer is going to use the PACKAGE PARAMETERS, there must be a PACKAGE file entry. Then, create an entry in the PACKAGE PARAMETERS multiple within the ORDER PARAMETERS file (#100.99). The .01 field of this multiple is a DINUMed pointer to the PACKAGE file entry. This implies that the namespace must be the same as that used for the init.
  
  
• Whether the Order Entry init is built from the PACKAGE PARAMETERS or on the fly, next run the ORVOM routine. The ORVOM routines look at the PACKAGE PARAMETERS (if they exist) or prompt the developer for the names of protocols to be sent. They build ONIT routines that are similar to inits but contain only PROTOCOL file entries. The code generated in these routines installs and resolves pointers on the PROTOCOL file entries. (The ORVOM routines are part of the Order Entry package and are maintained by the Order Entry developers. They were reviewed by the VA FileMan developers.)
  
  
• If the init is being built from an entry in the PACKAGE file, enter the namespaced ONIT routine into the POST-INITIALIZATION ROUTINE field in the PACKAGE file entry. It will be run automatically as a post-init.
  
  If the init is not being built from the PACKAGE file, the developer must tell the installers to run the ONIT routines manually AFTER they run the init routines.
  
  
• Now, build the actual init using DIFROM in a normal way as described above.

DIFROM has been modified for Order Entry to automatically pick up the entry from the PACKAGE PARAMETERS multiple of the ORDER PARAMETERS file. When the init is run any pointers back to the PROTOCOL file that are contained in this entry are resolved. See the documentation on "Running an Init" for more information about resolving pointers during package installation.

Reviewed/Updated: March 10, 2007