a. Modifications to national package data dictionaries should be restricted to the addition of new data elements and to the creation of input and output templates to meet specific needs of local sites. To ensure the capability of installing new releases of the application packages, it is important that any local additions to the data base be made in areas that will not conflict with elements contained in the nationally distributed data base.

b. When adding new data elements to the VA FileMan data dictionary, the numbering conventions used for creating new files should also be used for data elements.

(1) A data element number should be entered that is in the numbering range of the assigned numbering prefix multiplied by 1000.

(2) The same convention should be applied to global subscripts for local data add-ons to previously defined globals.

c. The VA FileMan subdictionary numbers should be assigned at the high end of the numbering sequence, following the numbering convention outlined. For example, a VA FileMan subdictionary number added to the Patient file (File 2) by station 368 should be 2.368001, a second subdictionary should be assigned 2.368002, and so forth.

d. The VA FileMan data dictionary may be modified only through tools provided by the VA FileMan or by tools specifically referenced in the VA FileMan Programmer's Manual.

e. To keep conflicts with cross-references to a minimum, field facilities creating custom cross-references must use the number range assigned to the site and prefix with "AZ" or "Z".

(1) National packages are not permitted to use these cross-references.

(2) Cross-reference numbers should be assigned based on the station number multiplied by 1000.

f. All other types of local data modifications to national packages are strongly discouraged. If local modifications are made to existing data elements in a national package data dictionary, it will then be the responsibility of the site to maintain those modifications as new versions of the package are installed.

g. When software components are incorporated into the package, the names associated with the new components (e.g., routines, options, templates) should be prefixed by the package namespace followed by the letter "Z".

(1) For example, a local option called "LOG" for the PSIV package would have the option name "PSIVZLOG".

(2) Prefixing allows the site to readily differentiate between components developed locally and those associated with the DHCP national packages.

(3) Namespaces of one, two, three, or four characters followed by "Z*" shall not be exported in nationally developed software, but shall be reserved for local use.