I want to avoid that people produce a record from a file twice!
You have two options Mark Done and X-Out. Both are real-time, that is they are performed on the file while producing, record for record.
Note: to protect the files from corruption because of power outages, please make sure you use an Uninterruptible Power Supply.
Description Mark Done
Mark Done uses one column from the original file. The data in the column must originally be blank or space. As the controller produces, it will put a “1” in the column for all records produced. If the supervisor allows to reproduce a record, you will find a “2”, that is that record was produced twice !.
In below example, you that the Mark Done column was set at position 12 and is of length 1 (see also X-out, length greater than 1). Below, you that records 100 to 103 were produced twice “2”. Records 104 to 115 were produced once “1”. Red stands for already produced.
Mark Done can be used to X-out part or the whole record from the original file. As the controller produces, it will put an “X” in the selected columns for all records produced. That means, if the operator goes back, it will print Xs and not anymore the original values because they do not exist anymore!
The only way to produce again the same record is to reload the file. Please implement procedures so that your operator can load a file only once into the controller!
In below example, you that the Mark Done column was set at position 14 and is of length 32 (see also Mark Done, length not 1 switches to Mark Done). Below, see you that records 32 to 45 were produced and Xed out.