SQL Server trigger interfering with select statement - sql

Question

We have a trigger on a table that fires during an update. We use Entity Framework on the front end. So, we don't want to see the intermediate results (the results from the trigger) when we do an update. I have SET NOCOUNT ON in my trigger:
ALTER TRIGGER [dbo].[trgForMedCMDWorkItemsUpdate]
ON [dbo].[MedCMDWorkItems]
AFTER UPDATE
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
But when we execute the update, we see the intermediate results first and that throws Entity Framework.
Here is the sql command:
Declare #UserID int
set #UserID = 26
declare #WorkItemID int
Declare #UserRoles TABLE ( roleid INT ,parentroleid INT ,rolename VARCHAR(100) )
INSERT INTO #UserRoles SELECT R.id,R.parentroleid,R.ROLE FROM userroles UR
INNER JOIN roles R ON UR.roleid = R.id WHERE UR.userid = #UserID
Update MedCMDWorkItems with (UPDLOCK) Set AssignedTo = #UserID, AssignedAt =
getdate(), LastUpdatedAt = getdate(), LastUpdatedBy = #UserID, #WorkItemID =
ID
where ID = (SELECT TOP 1 PR.ID FROM MedCMDWorkItems PR --with (UPDLOCK)
JOIN TaskTypes TT on PR.TaskTypeID = TT.ID WHERE PR.AssignedTo IS NULL AND
PR.ClosedAt IS NULL
AND Exists (SELECT 1 FROM #UserRoles WHERE roleid in (852,772)) AND
((PR.WorkItemTypeID = (select 29 FROM #UserRoles UR WHERE UR.RoleID = 852)
AND TT.Task in (SELECT Substring(UR1.rolename, Charindex('|', UR1.rolename)
+ 1, Len(UR1.rolename)) FROM #UserRoles UR1 WHERE UR1.parentroleid in (852))
) OR
(PR.WorkItemTypeID = (select 28 FROM #UserRoles UR WHERE UR.RoleID = 772)
AND TT.Task in (SELECT Substring(UR1.rolename, Charindex('|', UR1.rolename)
+ 1, Len(UR1.rolename)) FROM #UserRoles UR1 WHERE UR1.parentroleid in (772))
) )
ORDER BY (CASE WHEN PR.IsUrgent IS NULL THEN 'False' ELSE PR.IsUrgent END)
DESC, ( CASE WHEN PR.Priority IS NULL THEN 9999 ELSE PR.Priority END ),
PR.CreatedAt)
Select * From MedCMDWorkItems PRI Where ID = #WorkItemID
Here is the trigger:
USE [CombinedWorkflow]
GO
/****** Object: Trigger [dbo].[trgForMedCMDWorkItemsUpdate] Script Date:
4/3/2018 5:20:22 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER TRIGGER [dbo].[trgForMedCMDWorkItemsUpdate]
ON [dbo].[MedCMDWorkItems]
AFTER UPDATE
AS
BEGIN
SET NOCOUNT ON;
declare #NewAssignedAt DateTime;
declare #OldAssignedAt DateTime;
declare #NewPulledAt DateTime;
declare #ID int;
select #NewPulledAt = i.PulledAt from inserted i;
select #NewAssignedAt = i.AssignedAt from inserted i;
select #OldAssignedAt = d.AssignedAt from deleted d;
select #ID = i.ID from inserted i;
--If work item is being un-assigned
if(#OldAssignedAt is NOT NULL and #NewAssignedAt is NULL)
BEGIN
SET NOCOUNT ON;
Update MedCMDWorkItems
Set PulledAt = NULL
Where ID = #ID
END
--if work item is being assinged
ELSE if(#NewAssignedAt IS NOT NULL)
BEGIN
SET NOCOUNT ON;
Update MedCMDWorkItems
Set FirstAssignedAt = #NewAssignedAt
Where FirstAssignedAt is NULL and ID = #ID
END
-- if work item is being pulled
ELSE if(#NewPulledAt IS NOT NULL)
BEGIN
SET NOCOUNT ON;
Update MedCMDWorkItems
Set AssignedAt = #NewPulledAt
Where AssignedAt is NULL and ID = #ID
SET NOCOUNT ON;
Update MedCMDWorkItems
Set FirstAssignedAt = #NewPulledAt
Where FirstAssignedAt is NULL and ID = #ID
END
Select 1
END
When I execute in SSMS with the trigger on under results, I get 2 results, first indicating 1 row was updated, then a second indicating the results of the query.
If I disable the trigger and execute the command I don't get the first result, and that is my desired behavior with the trigger enabled.
How do I set this trigger up so it fires but does not cause the additional results?
Thanks,
Sammer

Answer 1

you need to use inserted and deleted as tables, they can hold more than one row so you never can fill a variable from it.
In stead you have to build it like this example :
your code (first part of it)
ALTER TRIGGER [dbo].[trgForMedCMDWorkItemsUpdate]
ON [dbo].[MedCMDWorkItems]
AFTER UPDATE AS
BEGIN
SET NOCOUNT ON;
declare #NewAssignedAt DateTime;
declare #OldAssignedAt DateTime;
declare #NewPulledAt DateTime;
declare #ID int;
select #NewPulledAt = i.PulledAt from inserted i;
select #NewAssignedAt = i.AssignedAt from inserted i;
select #OldAssignedAt = d.AssignedAt from deleted d;
select #ID = i.ID from inserted i;
--If work item is being un-assigned
if(#OldAssignedAt is NOT NULL and #NewAssignedAt is NULL)
BEGIN
SET NOCOUNT ON;
Update MedCMDWorkItems
Set PulledAt = NULL
Where ID = #ID
END
can be replaced by something like this (not tested because i dont have your database)
ALTER TRIGGER [dbo].[trgForMedCMDWorkItemsUpdate]
ON [dbo].[MedCMDWorkItems]
AFTER UPDATE AS
BEGIN
SET NOCOUNT ON;
update MedCMDWorkItems
Set PulledAt = NULL
where ID in ( select i.Id
from Inserted i
left join deleted d on i.Id = d.Id
where d.AssignedAt is not null
and i.AssignedAt is null
)
Once you get this it will not be so hard to figure out how to adjust the rest of your trigger

Answer 2

Thanks everyone for the input. I figured out the issue. The trigger had this at the end:
...
END
-- if work item is being pulled
ELSE if(#NewPulledAt IS NOT NULL)
BEGIN
SET NOCOUNT ON;
Update MedCMDWorkItems
Set AssignedAt = #NewPulledAt
Where AssignedAt is NULL and ID = #ID
SET NOCOUNT ON;
Update MedCMDWorkItems
Set FirstAssignedAt = #NewPulledAt
Where FirstAssignedAt is NULL and ID = #ID
END
Select 1
END
No idea what that last line (Select 1) is supposed to be for (I didn't write the trigger :)), but it was causing the unwanted results being displayed.
Sammer