Summary of a Data Dictionary Process
Components of the data dictionary are only processed when necessary. Refer to the Tracking Processing Requirements section later in this chapter for additional information.
For those domains, files, fields, and work fields that do need processing, the following actions occur:
Domains are processed before any fields in the dictionary.
Fields are converted (in sequence number order) to a format more directly executable by processes within APPX. Attributes defined at the domain level are incorporated into the new format, and all overrides are resolved. Storage lengths for fields are calculated. The resulting processed fields are called elements.
Files are processed to reflect changes to file specifications or to field specifications that affect a processed file, such as the various primary and alternate key specifications.
Default value specifications are converted to an internal format and stored in an initial value record for each file. A null value record for each file is also created.
Data is subjected to a limited validation. This validation is required because specifications may have been imported (either through the migration utility or a user-designed process), thus bypassing the error checks incorporated in APPX's data dictionary input processes.
If modifications result in structural changes, a date/time field is updated, indicating the point where the structure changed.
A list of all the errors APPX encounters is generated at the end.
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