ENFORM User's Guide

2 Developing the Data Base
058058 Tandem Computers Incorporated 2–1
ENFORM enables you to retrieve data from a data base. This section discusses some
of the tasks involved in developing or producing a data base. It does not recommend
a method of data base design. Data base design is a complex task, one that is beyond
the scope of this guide.
Before performing the tasks described in this section, it is important to understand the
characteristics of the data that comprise a data base.
What is a Data Base? A data base is a collection of data that is stored and used for multiple purposes.
Usually many different kinds of applications access a data base that contains many
different types of data. Thus, a data base serves as a repository for the data needed to
perform certain functions in a commercial, scientific, or business enterprise.
Fields The smallest named unit of data in a data base is a field. Each field has a name and
occupies a specific location in relation to other fields.
Fields can contain data that belongs to one of two data categories: either alphanumeric
or numeric. Alphanumeric fields contain data composed of letters of the alphabet,
spaces, digits, and special symbols like the hyphen. Numeric fields contain digits,
minus or plus signs, and decimal points.
The characters that are stored in a field are called the field value. When more than one
value is associated with a field, the field is said to contain repeating field values. The
field itself is called a repeating group.
Records A record (sometimes called a record-type) is a collection of associated fields. Each
record has a name. Consider Figure 2-1 which shows the records named parts and
odetail.
Figure 2-1. Sample Records
partnum
parts
partname inventory location price
ordernum
odetail
partnum quantity
The record parts consists of the fields: partnum, partname, inventory, location, and price.
The record odetail consists of the fields ordernum, partnum, and quantity.
No field values are associated with a record; instead a record acts as a framework into
which specific field values can be fitted. Usually many different types of records exist
within a data base, with each different type of record having its own set of record
occurrences.