数据库角色管理，已经可以使用alter role，create role和drop role。
2012增加了几个ddl语句，可以操作服务级别的角色管理，
CREATE SERVER ROLE
用来创建服务级别的role。
CREATE SERVER ROLE DBA
SELECT name, type_desc FROM sys .server_principals WHERE type = 'R' AND name ='DBA'
name type_desc
-------------------------------------- ------------------------------------------------------------
DBA SERVER_ROLE
ALTER SERVER ROLE
用来修改服务级别的角色
ALTER SERVER ROLE DBA ADD MEMBER fanr
SELECT b. name, c. name FROM sys . server_role_members a
INNER JOIN sys .server_principals b ON a. role_principal_id = b .principal_id
INNER JOIN sys .server_principals c ON a. member_principal_id =c .principal_id
WHERE b. name= 'DBA'
name name
---------------------------------------
DBA fanr
ALTER SERVER ROLE dba DROP MEMBER fanr
SELECT b. name, c. name FROM sys . server_role_members a
INNER JOIN sys .server_principals b ON a. role_principal_id = b .principal_id
INNER JOIN sys .server_principals c ON a. member_principal_id =c .principal_id
WHERE b. name= 'DBA'
name name
-------------------------- ---------------------
( 0 row (s ) affected )
DROP SERVER ROLE
删除服务级别角色
DROP SERVER ROLE dba
