DML Statements or Data Manipulation Language statements will not be committed unless they are committed explicitly, But if you use any data definition language (DDL) statement before or after , then Oracle Database issues an implicit COMMIT.
There is a provision in Oracle to commit every DML Transaction automatically once its run. This is called AUTOCOMMIT. We can also turn AUTOCOMMIT on and off based on our requirement.
When AUTOCOMMIT IMMEDIATE is activated all the DML statements executed afterward will be treated as a transaction and will be committed to the Database.