Beginning with Oracle Database 10g, executed DROP USER CASCADE command will not only remove the user but also all associated objects and datafiles. This functionality can simplify the process of dropping users, especially when you are unsure about what objects the user owns. Nevertheless, it should be used with caution, as data loss is irreversible.
The necessity of deleting users arises for many reasons such as essential database housekeeping, removing unwanted and unused users, or maybe the user belongs to an employee that has left the company. So, handling this process becomes important.
Let’s first step into the solution we offer for dropping a user in Oracle SQL.
Oracle SQL provides a simple and straightforward command which is DROP USER. We can enhance it to DROP USER CASCADE to remove all associated elements with the user.
The syntax of the DROP USER command is simple: DROP USER username CASCADE;
Step-by-step Explaination of the Code
The “DROP USER” is an Oracle SQL command, and “username” should be the name of the user account that you intend to delete. The “CASCADE” keyword signifies that you not only want to drop this user, but also want to remove any database objects owned by this user.
Let’s say we have a user called “test_user” , and we want to remove this user, including all objects that belong to him. We would simply run the following command:
DROP USER test_user CASCADE;
After running the above command, “test_user” and all objects associated with it would be completely removed from your Oracle database.
Error Handling and Additional Considerations
While it is simple to drop users with the DROP USER CASCADE command, there are a few caveats you should bear in mind. The user needs to be disconnected from the database. An active session will cause an error. You also should be sure that no other users are referencing objects of the user being dropped, as these references will be left hanging.
The DROP USER CASCADE command is irreversible and you will permanently lose all the user’s objects and associated datafiles. So it is always advisable to keep a good recent backup of the database.
Related Functions and Procedures
There are other related SQL commands to DROP USER CASCADE. One of them is ALTER USER. It allows you to modify an existing user. Another is CREATE USER, which you might need after dropping a user if you’re planning to create a new user with the same name or maybe you accidently dropped the wrong user.
It is always a best practice to control and keep track of user accounts within your databases. Careful management and cleaning of these accounts should become part of your routine as a database administrator.