I think logical backup and recovery using the exp and imp utilities are also very useful and important as it allows to take backup of selected objets in the schema (with or without data).
-----------------------------------------------------------[font=Arial Black]Time Is Money[/font][font=Arial Narrow]Calculating the Number of Business Hours Passed since a Point of Time[/url][/font][font=Arial Narrow]Calculating the Number of Business Hours Passed Between Two Points of Time[/font]