Explanation:
To perform a consistent whole database backup, you must first shut down the database with one of the following options: NORMAL, TRANSACTIONAL, or IMMEDIATE. The ABORT option shuts the database without finishing the checkpointing on all the data files. You will need to perform recovery after restoration to bring the database into a consistent state.
Reference:
Oracle 9i Net Services Administrator’s Guide
Oracle 9i Net Services Reference Guide
Oracle 9i Recovery Manager Reference
Oracle 9i Backup and Recovery Concepts

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