Difference between SET autocommit=1 and START TRANSACTION in mysql (Have I missed something?)

Question

I am reading up on transactions in MySQL and am not sure whether I have grasped something specific correctly, and I want to be sure I understood that correctly, so here goes

Answer 1

If you want to use rollback, then use start transaction and otherwise forget all those things,

By default, MySQL automatically commits the changes to the database.

To force MySQL not to commit these changes automatically, execute following:

SET autocommit = 0;
//OR    
SET autocommit = OFF

To enable the autocommit mode explicitly:

SET autocommit = 1;
//OR    
SET autocommit = ON;