回復到儲存點

PostgreSQL 的交易與錯誤處理

Jason Myers

Principal Engineer

未使用儲存點

BEGIN TRANSACTION;

UPDATE cost = 2.33 WHERE name = 'Linga';

UPDATE cost = 500 WHERE name = 'Macaron';

ROLLBACK;

使用儲存點與指定回復

BEGIN TRANSACTION;

UPDATE cost = 2.33 WHERE name = 'Linga';


SAVEPOINT oops;


UPDATE cost = 500 WHERE name = 'Macaron';


ROLLBACK TO oops;

用完後釋放儲存點

BEGIN TRANSACTION;

UPDATE cost = 2.33 WHERE name = 'Linga';
UPDATE cost = 2.33 WHERE name = 'Petit-Beurre';
UPDATE cost = 2.33 WHERE name = 'Rosette';

SAVEPOINT oops;

UPDATE cost = 5.00 WHERE name = 'Macaron';
UPDATE cost = 3.50 WHERE name = 'Panellets';

RELEASE SAVEPOINT oops;

回復與儲存點的兩個重點

不帶 TO 的 ROLLBACK 會回復整個交易
ROLLBACK TO ___ 若 ___ 不是有效的儲存點名稱，會發生錯誤

一起來練習吧！

PostgreSQL 的交易與錯誤處理