There can be more than one index to an ISAM file. The index key for this file must be unique. Batch processing is usually used in accounting systems. Manual processing systems usually use batch processing. The general journal is an example of a manual tx file.
Batch processing leaves a clear audit trail.
Batch processing allows easier disaster recovery. Processing takes place during peak computer use periods. Audit trail is more difficult to establish. A mirrored site is needed for disaster recovery. Student details These files will have to be linked.