sql server触发器

sql server触发器

1.DML触发器

//DML触发器
CREATE TRIGGER [ schema_name . ]trigger_name 
ON { table | view } 
[ WITH <dml_trigger_option> [ ,...n ] ]
{ FOR | AFTER | INSTEAD OF } 
{ [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } 
[ WITH APPEND ] 
[ NOT FOR REPLICATION ] 
AS { sql_statement  [ ; ] [ ,...n ] | EXTERNAL NAME <method specifier [ ; ] > }
 
<dml_trigger_option> ::=
    [ ENCRYPTION ]
    [ EXECUTE AS Clause ]
<method_specifier> ::=

   assembly_name.class_name.method_name

create trigger tri_update
on student
for update
as
if update(student_id)
begin
raiserror('学号不能修改!',16,8)
rollback tran
end
go

2.DDL触发器

CREATE TRIGGER trigger_name 
ON { ALL SERVER | DATABASE } 
[ WITH <ddl_trigger_option> [ ,...n ] ]
{ FOR | AFTER } { event_type | event_group } [ ,...n ]
AS { sql_statement  [ ; ] [ ,...n ] | EXTERNAL NAME < method specifier >  [ ; ] }
 
<ddl_trigger_option> ::=
    [ ENCRYPTION ]
    [ EXECUTE AS Clause ]
 
<method_specifier> ::=
    assembly_name.class_name.method_name

CREATE TRIGGER safety 
ON DATABASE 
FOR DROP_TABLE, ALTER_TABLE 
AS 
   PRINT 'You must disable Trigger "safety" to drop or alter tables!' 
   ROLLBACK;

3.登录触发器

//登录触发器
CREATE TRIGGER trigger_name 
ON ALL SERVER 
[ WITH <logon_trigger_option> [ ,...n ] ]
{ FOR| AFTER } LOGON  
AS { sql_statement  [ ; ] [ ,...n ] | EXTERNAL NAME < method specifier >  [ ; ] }
<logon_trigger_option> ::=
    [ ENCRYPTION ]
    [ EXECUTE AS Clause ]
 
<method_specifier> ::=
assembly_name.class_name.method_name

CREATE TRIGGER connection_limit_trigger
ON ALL SERVER WITH EXECUTE AS 'login_test'
FOR LOGON
AS
BEGIN
IF ORIGINAL_LOGIN()= 'login_test' AND
    (SELECT COUNT(*) FROM sys.dm_exec_sessions
            WHERE is_user_process = 1 AND
                original_login_name = 'login_test') > 3
    ROLLBACK;
END;