MySQL basic tutorial -- MySQL transaction and storage engine

One 、 What is business ？

--  An important concept and specific operation of transaction 
--  demonstration 
-- 1.  Create a test table 
CREATE TABLE t27
	( id INT,
	  `name` VARCHAR(32));
-- 2.  Start business 
START TRANSACTION 
-- 3.  Set the savepoint 
SAVEPOINT a
--  perform dml  operation 
INSERT INTO t27 VALUES(100, 'tom');
SELECT * FROM t27;

SAVEPOINT b
--  perform dml operation 
INSERT INTO t27 VALUES(200, 'jack');

--  Back to  b
ROLLBACK TO b
--  Keep going back  a
ROLLBACK TO a
--  If so ,  It means to directly back to the start of the transaction .
ROLLBACK 
COMMIT

Two 、 Business details

-- 1.  If you don't start a transaction , By default ,dml Operations are automatically submitted , Cannot be rolled back 
INSERT INTO t27 VALUES(300, 'milan'); --  Automatic submission  commit

SELECT * FROM t27

-- 2.  If you start a transaction , You didn't create a savepoint .  You can execute  rollback,
--  The default is to go back to the beginning of your transaction 
START TRANSACTION 
INSERT INTO t27 VALUES(400, 'king');
INSERT INTO t27 VALUES(500, 'scott');
ROLLBACK --  Indicates the state of directly backing back to the beginning of the transaction 
COMMIT;

-- 3.  You can also be in this business ( Before it's submitted ),  Create multiple savepoints . such as : savepoint aaa; 
--  perform  dml , savepoint bbb
-- 4.  You can do this before the transaction is committed , Choose which savepoint to go back to 
-- 5. InnoDB  Storage engine support transactions  , MyISAM  I won't support it 
-- 6.  Start a transaction  start transaction, set autocommit=off;

3、 ... and 、 Transaction isolation level

Four 、MySQL Business ACID

5、 ... and 、 Storage engine overview

Reference resources b Station hanshunping teacher video ：https://www.bilibili.com/video/BV1H64y1U7GJ