How database files are described
Records in database files can be described to the field or record level.
- Field-level description. The fields in the record are described to the system. For each field you can describe the name, length, data type, and validity checks. You can also add a text description. Database files that are created with field-level descriptions are referred to as externally described files.
- Record-level description. Only the length of the record in the file is described to the system. The system does not know about fields in the file. These database files are referred to as program-described files.
Whether a file is described to the field or record level, you must describe and create the file before you can compile a program that uses that file. That is, the file must exist on the system before you use it.