实例理解SQL中truncate和delete的区别

---创建表Table1
IF OBJECT_ID('Table1','U') IS NOT NULL
DROP TABLE Table1
GO
CREATE TABLE Table1
(ID INT NOT NULL,
FOID INT NOT NULL)
GO
--插入测试数据
INSERT INTO Table1
VALUES(1,101),(2,102),(3,103),(4,104)
GO
---创建表Table2
IF OBJECT_ID('Table2','U') IS NOT NULL
DROP TABLE Table2
GO
CREATE TABLE Table2
(
FOID INT NOT NULL)
GO
--插入测试数据
INSERT INTO Table2 VALUES(101),(102),(103),(104)
GO 
SELECT * FROM Table1
GO 
SELECT * FROM Table2
GO

CREATE TRIGGER TG_Table1 ON Table1
AFTER DELETE
AS
BEGIN
 DELETE FROM TA FROM Table2 TA INNER JOIN deleted TB ON TA.FOID=TB.FOID 
END
GO

---测试DELETE删除操作
DELETE FROM Table1 WHERE ID=1
GO
---执行触发器成功,Table2表中的FOID=101的数据也被删除
SELECT * FROM Table1
GO
SELECT * FROM Table2

---测试TRUNCATE删除操作
TRUNCATE TABLE Table1
GO
---Table2中的数据没有被删除
SELECT * FROM Table1
GO
SELECT * FROM Table2

---查看TRUNCATE和DELETE的日志记录情况
CHECKPOINT
GO
SELECT * FROM fn_dblog(NULL,NULL)
GO
DELETE FROM Table2
WHERE FOID=102
GO
SELECT * FROM fn_dblog(NULL,NULL)

----TRUNCATE日志记录
CHECKPOINT
GO
SELECT * FROM fn_dblog(NULL,NULL)
GO
TRUNCATE TABLE Table2
GO
SELECT * FROM fn_dblog(NULL,NULL)
GO