The Field Length value is the size in bytes of the internal representation of a field as shown below:
character The total number of character positions required for the longest entry.
string The total number of character positions required for the longest entry plus one character position for the terminator character required by string fields.
money/real The allowed Field Length is determined by the machine. Most machines accept 8 or 4. You should enter the default Field Length by leaving the Field Length blank and pressing RETURN.
integer The allowed Field Length is determined by the machine. Most machines accept 4 or 2. You should enter the default Field Length by leaving the Field Length blank and pressing RETURN.
boolean The allowed Field Length is determined by the machine. Most machines accept 1. You should enter the default Field Length by leaving the Field Length blank and pressing RETURN.
date/time The allowed Field Length is determined by the machine. Most machines accept 4. You should enter the default Field Length by leaving the Field Length blank and pressing RETURN.