The numeric sequence entry combined with the number (position 19) and option (position 20) entries causes the program to check the sequence of input records within a file. If the sequence is not correct, control passes to the RPG IV exception/error handling routine. If AND or OR lines are specified, the sequence entry is made on the main record line of the group, not on the AND or OR lines.
Alphabetic and numeric entries can be made for different records (different record identification lines) in the same file, but records with alphabetic entries must be specified before records with numeric entries.