What is the difference between INSERT/UPDATE DML and Database.insert/Database.update?

DML statements (insert records;): If any record in the batch fails, the entire operation is rolled back and an exception is thrown. All or nothing. Database methods (Database.insert(records, false);): The second parameter allOrNone — when set to false, allows partial success. Records that pass validation are committed; failed records are captured in Database.SaveResult. Returns a list of SaveResult objects, each with isSuccess(), getErrors(), and the record Id. Use partial DML when processing a batch where some records may legitimately fail and you want to continue processing the rest. Use allOrNone DML when data integrity requires all records to succeed together (transactional requirement).