The decode feature reassures operators learning new codings that they have indeed learned correctly, and is very useful in query mode to elucidate the data for people less familiar with the codes. They easily become a part of the entry sequence. Nothing happens to the record until a command and the escape key are entered. The whole record is validated again before it is written. Messages appear on the bottom three lines to ack- nowledge correct seeks and writes, explain errors, etc.
Data validation is very extensive.
There are over twenty validation types including two which are used to specify arbitrary lists or ranges of values. A decode table may also be specified as the valid value list. Then operators can be trained on line and sample reports run. It is a simple process to expand the database later to include new fields, add decode tables, add titles and foot- notes to reports, and have the system grow and change to meet your needs. Many options may be specified by the database administrator.