Postalsoft Business Edition User's Guide 8.00c ... - SAP Help Portal

Three file types
Mailing description
file (.mdf)
The file you create and work in is called the mailing description file. It has the
extension of .mdf (for example, customer.mdf). Think of the mailing description
file as a tool you use to view and manipulate the information in the database. In
the mailing description file, you can perform certain tasks with the information
stored in the database file (such as correcting addresses).
The mailing description file contains many of your settings. These settings stay
with your mailing description file and will not change until you change them.
Two or more users cannot access the same mailing description file
simultaneously. For example, if Mary is working in the customer.mdf file on her
computer, John cannot open and work in the customer.mdf file on his computer
at the same time.
Database file (.dbf)
The database file (.dbf) contains data for every field in every record and is dBasecompatible.
Typically the data includes name and address information. However,
you can create your own non-address fields.
Data that you add is placed into the database file. When you add a new record,
other users sharing the same database file will then have access to that new
record.
The database file doesn’t have to be named with the same root name as your
mailing description file. And you can have more than one .mdf file associated
with a .dbf file. For example, you could have a database file called main.dbf, and
it could be associated with customer.mdf, fallsale.mdf, and select.mdf.
Index file (.cdx)
The index file keeps track of which fields are indexed—that is, which fields you
can sort by (last name, ZIP Code, and so on). The index file is connected to the
database file and is updated each time you add or change data. It has the extension
of .cdx (for example, main.cdx).
The index file’s root name will always be the same as the database (.dbf) file’s
root name.
26 Business Edition User’s Guide