When you creating RMSfiles, each of the following must be defined:
1) File Access Method
2) Primary Key Ordering
3) Duplicate Key Handling
4) Field Descriptions
5) Primary Key Field Names
6) Secondary Key Field Names
Each of these is discussed in detail in C/Base Reference Manual Chapter 4, Creating RMSfiles. In this chapter, however, we will only concern ourselves with items 4-6 and simply use the default values for items 1-3.
As we continue with the next exercise in this chapter, youll discover that there are four different forms which together define the structure of a RMSfile. The first form is used to define items 1-3. The values entered in the fields of this form determine how records are stored in and retrieved from the RMSfile. The next form defines the individual field descriptions. This form repeats once for each field to be defined in the RMSfile. The third form is used to enter the primary key field names. The primary key of a RMSfile determines where a record is physicallystored within the RMSfile. This form does not repeat, since only one primary key set is allowed. The last form defines the secondary key field names. Secondary keys allow quick access to records by fields other than those that uniquely identify the record, i.e., the primarykey field(s). This form repeats once for each secondary key field 'set' defined.