Once AUTOCOMMIT is set on, changes will be made automatically at the end of every SQL statement.

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:

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.

UPDATE employee SET salary = 50000 WHERE employee_id = 1;

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:

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!

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