IDENTITY_INSERT

设定　SET IDENTITY_INSERT

建立一个有标识列的表：
CREATE TABLE products (id int IDENTITY PRIMARY KEY, product varchar(40))

尝试在表中做以下操作：
INSERT INTO products (id, product) VALUES(3, 'garden shovel')

结果会导致错误

改用：
SET IDENTITY_INSERT products ON
INSERT INTO products (id, product) VALUES(1, 'garden shovel')

返回正确。