Worst recovery case ... ever.
Oracle DMP files generated by 'exp' are not considered as a backup. In a sense that is correct.
If you run 'exp' on a live database, data in your dump file can be inconsistent. This can be an issue when you export for example tables with a parent-child relationship.
Or for example - while performing full exports and tables are using a surrogate primary key. Typically a sequence is used, but the sequences are exported at a different point of the export flow. This means that sequences can become out-of-sync with the table data. Anyway, some of these issues are handled by the CONSISTENT parameter.
The main reason DMP files became legacy is the fact that we live in a 24/7 world (or 25/8 for dba's & sysadmins) - and DMP files are just a snapshot of your data in time, and thus are basically useless from the moment the file hits your disk. They are only vaguely useful now when it comes to having a snapshot of your database object DDL.
I remember the days though, where we had databases that we could shut down during the night for a cold backup and a startup followed by an export ... those days are long gone.
However, somehow people are still very fond of the beloved exp/imp tools even as a backup.
Kurt Van Meerbeeck
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