Question

sqlserver中SET identity_insert on的问题！

/* Data for table DM_abhyasaDay */
SET identity_insert [dsc070763].[DM_abhyasaDay] on

SET identity_insert [dsc070763].[DM_abhyasaDay] off
GO
/* Data for table DM_abhyasaLong */
SET identity_insert [dsc070763].[DM_abhyasaLong] on

SET identity_insert [dsc070763].[DM_abhyasaLong] off
GO
/* Data for table DM_abhyasaWeek */
SET identity_insert [dsc070763].[DM_abhyasaWeek] on

SET identity_insert [dsc070763].[DM_abhyasaWeek] off
GO
/* Data for table DM_abhyasaYear */
SET identity_insert [dsc070763].[DM_abhyasaYear] on

SET identity_insert [dsc070763].[DM_abhyasaYear] off
GO
/* Data for table DM_book */
SET identity_insert [dsc070763].[DM_book] on

SET identity_insert [dsc070763].[DM_book] off
GO
这段代码什么意思？

Answer 1

一般字段如果是identity的，比如定义的时候nameid identity（1，1)就是说从1开始增长，每次加1，那么插入一条记录nameid字段是不需要赋值(一般也不允许）。那么有时候想自己插入nameid字段值，就用set identity_insert on就可以手动插入了。

Answer 2

SET identity_insert on使表中的identity字段可以插入自定的数据，否则只能系统自增