触发器失败总是会导致事务回滚,因此它不能执行任何事务操作,例如调用sp_send_dbmail
. 一个技巧是利用自定义分析器跟踪事件,因为它们是在独立事务中发送的:
create queue q;
create service sq
on queue q
([http://schemas.microsoft.com/SQL/Notifications/PostEventNotification]);
go
create event notification trace_user_0
on server
for TRC_USER_CONFIGURABLE
to service N'sq', N'current database';
go
create procedure usp_sq
as
begin
declare @dh uniqueidentifier,
@mt sysname,
@mb varbinary(max),
@mx xml;
begin transaction
receive top(1)
@dh = conversation_handle,
@mt = message_type_name,
@mb = message_body
from q;
if @mt = N'http://schemas.microsoft.com/SQL/Notifications/EventNotification'
begin
set @mx = cast(@mb as xml);
declare @eventText nvarchar(4000);
select @eventText = @mx.value (N'(//EVENT_INSTANCE/TextData)[1]', N'nvarchar(4000)');
exec sp_send_dbmail @subject = 'Error in trigger', @body = @eventText;
end
else if @mt in (
N'http://schemas.microsoft.com/SQL/ServiceBroker/Error',
N'http://schemas.microsoft.com/SQL/ServiceBroker/EndDialog')
begin
end conversation @dh;
end
commit
end
go
alter queue q with activation (
status = on,
max_queue_readers = 1,
execute as = 'owner',
procedure_name = 'usp_sq');
go
create table MyTable (a int);
go
create trigger MyTrigger
on MyTable
after insert
as
begin try
if rand() > 0.5
raiserror (N'Something horrible happend in this trigger!', 16,1);
end try
begin catch
declare @error_message nvarchar(256) = cast(error_message() as nvarchar(256));
exec sp_trace_generateevent 82, @error_message;
end catch
go
insert into MyTable (a) values (1);
insert into MyTable (a) values (2);
insert into MyTable (a) values (3);
insert into MyTable (a) values (4);
insert into MyTable (a) values (5);
insert into MyTable (a) values (6);
go