Database cloning is a procedure by which you can create an exact copy of an Oracle database without doing a full export/import. This method is used frequently by DBAs to update test or development environments from production.

As a rule, testing and development should not be done on your production database

Clone means an exact copy. That is, you will copy the very datafiles from your production database and use it to create your test database. So your test database will be a mirror image of the production in all respects, except of course, for the database name. We will be changing that.   The method used here is actually a backup/recovery of the production database on the test server