START TRANSACTION : Transaction « Procedure Function « MySQL Tutorial






mysql>
mysql> CREATE TABLE Employee(
    ->     id            int,
    ->     first_name    VARCHAR(15),
    ->     last_name     VARCHAR(15),
    ->     start_date    DATE,
    ->     end_date      DATE,
    ->     salary        FLOAT(8,2),
    ->     city          VARCHAR(10),
    ->     description   VARCHAR(15)
    -> );
Query OK, 0 rows affected (0.03 sec)

mysql>
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->              values (1,'Jason',    'Martin',  '19960725',  '20060725', 1234.56, 'Toronto',  'Programmer');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(2,'Alison',   'Mathews',  '19760321', '19860221', 6661.78, 'Vancouver','Tester');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(3,'James',    'Smith',    '19781212', '19900315', 6544.78, 'Vancouver','Tester');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(4,'Celia',    'Rice',     '19821024', '19990421', 2344.78, 'Vancouver','Manager');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(5,'Robert',   'Black',    '19840115', '19980808', 2334.78, 'Vancouver','Tester');
Query OK, 1 row affected (0.02 sec)

mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(6,'Linda',    'Green',    '19870730', '19960104', 4322.78,'New York',  'Tester');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(7,'David',    'Larry',    '19901231', '19980212', 7897.78,'New York',  'Manager');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(8,'James',    'Cat',     '19960917',  '20020415', 1232.78,'Vancouver', 'Tester');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> select * from Employee;
+------+------------+-----------+------------+------------+---------+-----------+-------------+
| id   | first_name | last_name | start_date | end_date   | salary  | city      | description |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
|    1 | Jason      | Martin    | 1996-07-25 | 2006-07-25 | 1234.56 | Toronto   | Programmer  |
|    2 | Alison     | Mathews   | 1976-03-21 | 1986-02-21 | 6661.78 | Vancouver | Tester      |
|    3 | James      | Smith     | 1978-12-12 | 1990-03-15 | 6544.78 | Vancouver | Tester      |
|    4 | Celia      | Rice      | 1982-10-24 | 1999-04-21 | 2344.78 | Vancouver | Manager     |
|    5 | Robert     | Black     | 1984-01-15 | 1998-08-08 | 2334.78 | Vancouver | Tester      |
|    6 | Linda      | Green     | 1987-07-30 | 1996-01-04 | 4322.78 | New York  | Tester      |
|    7 | David      | Larry     | 1990-12-31 | 1998-02-12 | 7897.78 | New York  | Manager     |
|    8 | James      | Cat       | 1996-09-17 | 2002-04-15 | 1232.78 | Vancouver | Tester      |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
8 rows in set (0.02 sec)

mysql>
mysql>
mysql>
mysql> delimiter $$
mysql>
mysql> create procedure myProc
    ->        (from_account int, to_account int,
    ->         tfer_amount numeric(10,2), OUT out_status INT,
    ->         OUT out_message VARCHAR(30))
    -> BEGIN
    ->
    ->      DECLARE deadlock INT DEFAULT 0;
    ->      DECLARE attempts INT DEFAULT 0;
    ->
    ->      tfer_loop:WHILE (attempts<3) DO
    ->           BEGIN
    ->                DECLARE deadlock_detected CONDITION FOR 1213;
    ->                DECLARE EXIT HANDLER FOR deadlock_detected
    ->                     BEGIN
    ->                          ROLLBACK;
    ->                          SET deadlock=1;
    ->                     END;
    ->                SET deadlock=0;
    ->
    ->                START TRANSACTION;
    ->
    ->                UPDATE employee
    ->                   SET salary=salary - tfer_amount
    ->                 WHERE id=from_account;
    ->
    ->                UPDATE employee
    ->                   SET salary=salary + tfer_amount
    ->                 WHERE id=to_account;
    ->
    ->                COMMIT;
    ->
    ->           END;
    ->           IF deadlock=0 THEN
    ->                LEAVE tfer_loop;
    ->           ELSE
    ->                SET attempts=attempts+1;
    ->           END IF;
    ->      END WHILE tfer_loop;
    ->
    ->      IF deadlock=1 THEN
    ->           SET out_status=-1;
    ->           SET out_message="Failed with deadlock for 3 attempts";
    ->
    ->      ELSE
    ->           SET out_status=0;
    ->           SET out_message=CONCAT("OK (",attempts," deadlocks)");
    ->      END IF;
    ->
    -> END$$
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> delimiter ;
mysql>
mysql> set @myMessage = '';
Query OK, 0 rows affected (0.00 sec)

mysql> set @myCode =0;
Query OK, 0 rows affected (0.00 sec)

mysql> call myProc(1,2,1000,@myCode, @myMessage);
Query OK, 0 rows affected (0.00 sec)

mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> select @myCode;
+---------+
| @myCode |
+---------+
| 0       |
+---------+
1 row in set (0.00 sec)

mysql> select @myMessage;
+------------------+
| @myMessage       |
+------------------+
| OK (0 deadlocks) |
+------------------+
1 row in set (0.00 sec)

mysql>
mysql> select * from Employee;
+------+------------+-----------+------------+------------+---------+-----------+-------------+
| id   | first_name | last_name | start_date | end_date   | salary  | city      | description |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
|    1 | Jason      | Martin    | 1996-07-25 | 2006-07-25 |  234.56 | Toronto   | Programmer  |
|    2 | Alison     | Mathews   | 1976-03-21 | 1986-02-21 | 7661.78 | Vancouver | Tester      |
|    3 | James      | Smith     | 1978-12-12 | 1990-03-15 | 6544.78 | Vancouver | Tester      |
|    4 | Celia      | Rice      | 1982-10-24 | 1999-04-21 | 2344.78 | Vancouver | Manager     |
|    5 | Robert     | Black     | 1984-01-15 | 1998-08-08 | 2334.78 | Vancouver | Tester      |
|    6 | Linda      | Green     | 1987-07-30 | 1996-01-04 | 4322.78 | New York  | Tester      |
|    7 | David      | Larry     | 1990-12-31 | 1998-02-12 | 7897.78 | New York  | Manager     |
|    8 | James      | Cat       | 1996-09-17 | 2002-04-15 | 1232.78 | Vancouver | Tester      |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
8 rows in set (0.00 sec)

mysql>
mysql> drop table Employee;
Query OK, 0 rows affected (0.00 sec)

mysql>








11.48.Transaction
11.48.1.START TRANSACTION
11.48.2.Start and commit a TRANSACTION
11.48.3.Commit an update in a procedure
11.48.4.savepoint example
11.48.5.ROLLBACK TO a save point in a procedure
11.48.6.Deal with cursor within a TRANSACTION
11.48.7.ROLLBACK in a procedure