Provides the interface for performing long-running database operations in incremental steps, allowing application programs to remain responsive to other events.

After an operation has begun, a standard interface is used to continue and complete all incremental operations. On successful return from one of the initiating functions, a step value is also returned. This gives the progress indication and is, initially, positive. This value should be passed into subsequent steps in the operation, each of which may decrement the value by some amount, although they are allowed to leave it unchanged. The value reaches zero, if, and only if the operation completes.

While an incremental operation is in progress, the database cannot be used for any other operations such as opening tables or preparing views.

Starting an incremental operation also requires that no rowsets are open on the database and that no commit is pending for data manipulation transactions.

If no explicit transaction has been started by the database, then an automatic transaction is begun when any incremental operation is started and is committed when complete or rolled back if the operation either fails or is abandoned prior to completion.