Once AUTOCOMMIT is set on, changes will be made automatically at the end of every SQL statement.
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# Understanding AUTOCOMMIT in SQL
In SQL, the term 'AUTOCOMMIT' might appear complex but it is rather straightforward. The statement in the quiz is indeed correct, once AUTOCOMMIT is set on, changes will be made automatically at the end of each SQL statement.
Essentially, AUTOCOMMIT is a session variable that determines whether changes to the database are automatically committed after every individual SQL statement. If AUTOCOMMIT is set to `ON`, it means that the modifications made by the SQL statements (like `INSERT`, `DELETE`, `UPDATE`, `REPLACE`, etc.) will automatically be permanent.
Below is an example:
```sql
SET AUTOCOMMIT=1;
DELETE FROM employees WHERE employee_id = 5;
```
In the above example, the `DELETE` statement will be committed automatically without having to explicitly use the `COMMIT` command because `AUTOCOMMIT` has been turned `ON`.
On the contrary, if AUTOCOMMIT is set to `OFF`, you will have to use `COMMIT` statement manually in order to save the changes to the database. Not doing so can lead to loss of changes made in that particular session in the event of an unexpected termination or failure.
```sql
SET AUTOCOMMIT=0;
UPDATE employee SET salary = 50000 WHERE employee_id = 1;
COMMIT;
```
In this case, the `UPDATE` command will not take effect until the `COMMIT` statement is carried out. This is useful because it allows for the ability to `ROLLBACK` or undo changes before the `COMMIT` statement is executed.
To sum up, enabling `AUTOCOMMIT` promotes convenience by automatically saving changes after every SQL statement, hence minimizing the risk of losing data during a session. On the flip side, this removes the flexibility of validating or undoing changes before they are permanently saved to the database. Therefore, it's imperative to cautiously use `AUTOCOMMIT` considering the trade-off between convenience and flexibility.
Bear in mind that the default setting of `AUTOCOMMIT` may vary depending on the SQL-dialect or the Database Management System (DBMS) you're using. Thus, it's always good practice to check the `AUTOCOMMIT` status before initiating a session. You can check it with:
```sql
SELECT @@autocommit;
```
This command will return the status of `autocommit` mode from your current SQL session, with `1` indicating `ON` and `0` indicating `OFF`.
Moderation in everything is key and database operations are no exception. Leverage `AUTOCOMMIT` judiciously for effective and efficient database operations. Happy coding!