--創建登錄賬號

create login username with password='password'

--創建數據庫用戶

create user username for login username

---授予該用戶對Student表的查詢權限，同時授予其進一步授權其他用戶的權利。

grant select

on student

to user_tom

with grant option

-----

create login marry with password='marry001'

create user user_marry for login marry

--創建角色

create role dbnormuser

---對角色授權

grant select

on student

to dbnormuser

--指定固定的服務器角色（登錄名）

sp_addsrvrolemember marry,sysadmin

刪除

 sp_dropsrvrolemember marry,sysadmin

--查看用戶

sp_helpuser

---新建外鍵約束

ALTER TABLE test_sub ADD CONSTRAINT main_id_cons FOREIGN KEY (main_id) REFERENCES test_main;

---刪除外鍵

ALTER TABLE test_sub drop CONSTRAINT main_id_cons

--創建級聯刪除外鍵

ALTER TABLE test_sub ADD CONSTRAINT main_id_cons FOREIGN KEY (main_id) REFERENCES test_main on delete

cascade

--創建級聯更新外鍵

ALTER TABLE test_sub ADD CONSTRAINT main_id_cons FOREIGN KEY (main_id) REFERENCES test_main on update

cascade

--創建刪除被參照主鍵是 鍵參照關系的外鍵設置為null

ALTER TABLE test_sub ADD CONSTRAINT main_id_cons FOREIGN KEY (main_id) REFERENCES test_main on update

set null

----參照完整性

不能刪除 帶有外鍵的記錄

關鍵字：sql server、數據庫、記錄