How to delete all tables and data belonging to a user in Oracle?

To delete all tables and data under a user, you can follow these steps:

1. Firstly, log in to the Oracle database using an administrator account, such as sys or system.
2. Identify the users to be cleared. You can use the following command to query the list of users in the database:
3. Show the usernames from the database for all users.
4. Find the user to be cleared.
5. Switch to the user you want to delete using the following command:
6. Change the current schema to the specified username.
7. Query the list of tables under a user using the following command:
8. Show the names of all tables from the user_tables.
9. Confirm the table you want to clear.
10. Delete tables one by one using the following command:
11. Delete the table named 表名.
12. Repeat the above steps to delete all tables that need to be cleared.
13. Before deleting the table, if you need to backup the table data, you can use the following command to export the table data to a backup file:
14. User name/password FILE=table_data_backup.dmp TABLES=(table_name1, table_name2, …);
15. This will create a backup file with a .dmp extension.
16. If you need to backup table data before deleting a table, you can use the following command to export the table data to a backup file:
17. Username/password FILE=backup_data_file.dmp TABLES=(table_name1, table_name2, …);
18. This will create a backup file with the extension .dmp.
19. Finally, delete the user using the following command:
20. Remove the user with specified username and all associated objects.
21. This will remove the user and all objects owned by them, including tables, views, indexes, etc.

Please note that removing all tables and data under a user is a risky operation, handle with caution and make sure to backup important data.