About the Multiple Files Concept
Mail.dat® is presented as a database consisting of files linked by Key Fields. There are 21 files, each with its own record type, from which recipients can extract any set of data serving their purpose. Mail.dat’s potential: serving recipient’s information needs efficiently and effectively while providing for all possible requests. Yet, only a limited number of the files will be used regularly.
Key Fields are those records within each file type that generate an additional record if any one of these fields, or combination thereof, has a change. For example, within the Container Summary file, the Job Id and Container ID fields are unique for a specific container; however, the remaining fields may be the same for two or more consecutive containers going to the same destination.
Key Fields provide linkage from one file to another. Deeper file levels require more Key Fields to insure corresponding specificity. Example: two fields define the records in the Container Summary file that belong to a Segment; however, four fields are necessary to define records in the Seed Name file belonging to a given Package Quantity record. Within each record layout, a Key field is identified with a “k”
Recognizing interacting criteria is fundamental to Mail.dat. For example, if within a single package multiple criteria vary simultaneously, then Mail.dat® may require as many Package Quantity records as there are pieces in the package. Consider 12 pieces in a package:
- 3 different Mail Piece Unit codes
- 6 subscription, 6 non-subscription
- 2 different 3-Digits (zoned).
These three interacting criteria could produce twelve combinations, each requiring a separate Package Quantity record. Understanding Key Fields is crucial to the successful linkage and implementation of Mail.dat; therefore, any element within the data can then be retrieved and output in the most convenient format. There are several inexpensive and powerful database software programs readily available that can easily process files presented in this manner.
