ENFORM User's Guide

Tasks Involved in Developing Your Data Base

Developing the Data Base

058058 Tandem Computers Incorporated 2–5

Figure 2-4. Record Occurrences With Normalized Data

partnum

244

2001

2403

4103

244

5103

6301

6402

Neworder Record Occurrences

ordate deldate

011078

012378

quantity custnum

• • • • • • • • • • • •• • •

ordernum

• • •

041078

061578

1234

7777

First normal form is a sufficient level of normalization for use with ENFORM;

however, further normalization might be desirable for other applications using the

data base. For example, neworder could be split into two records, order and odetail, as

shown in Appendix C.

Although normalization requires that some data values appear in more than one

record occurrence, normalization results in a considerable simplification of the data

structure. This simplification of the data structure allows ENFORM to operate

efficiently on the data base. It also makes the formation of ENFORM queries much

simplier.

Describing the Data Base Before using ENFORM to retrieve data, you must describe the data base fields,

records, and files. This description provides ENFORM with information about:

the name and length of each record.

the names, locations, lengths, and data categories (either alphanumeric or

numeric) of fields within each record.

the file structure and location of the physical file associated with each record.

the primary and alternate keys (if any) of each record.