They utilize the infrastructureresources and processes to avoid duplication of effort. Applications should be insulated from the details of each other's internal mechanisms. For example, internal changes in a new release of a purchased application should not force coordinated changes in other applications that share data. The intent is to be able to alter any one of the tiers, with minimal effect on the others. For example, a single business process should be invocable from a web form for individual actions, and from a batch process to deal with multiple actions.
Online processes provide immediate feedback to the user.
They typically address a single business transaction, although this is not a requirement, and are triggered by a business event. Batch processes are designed to process multiple records, are usually scheduled, and often perform maintenance functions on databases. As batch processing is often much cheaper to both develop and execute, it may still be preferable in many instances, though often considered passe. The building blocks of workflow. Often the building blocks of transactions.