3: Creating the Demonstration System Files

3.3 RMSfile Requirements

An RMSfile is a grouping of logically related records. Each record contains the same information, e.g., name, address, city, etc. These elements are called fields. A collection of RMSfiles is called a database.

When you create a database, you should group information for efficiency and economy so that the same data does not have to be stored in more than one file. For example, names and addresses of subscribers used for mailing magazines are kept in one file, while the actual subscription records are identified by subscriber code in another file. When the subscription file is accessed and the subscriber name is required, the subscriber file is accessed with the subscriber code as a key.

The first step in developing the Demonstration Subscription System is to define the RMSfiles. To do this, data fields for the three files described above must be defined.

a. mag: - This file contains pertinent information for each magazine. It contains the following fields:

These data fields are defined as follows:

b. sub: - This is the file that contains information on all subscribers. Each record in this file has the following data fields:

These fields are defined as follows:

c. script: This is a file containing a single record entry for each magazine subscription made by a subscriber. The fields for the subscription file are as follows:

These fields are further defined as follows: