Facing some problem in Instead of Trigger for MultiRow Insert

[santoshborfalkar]

This is the Trigger which is not working properly during Update, no any
record is going to be updated so pls help.

I am updating the requisition table when any update in quantity in
podetails table

CREATE TRIGGER trig_updateRequistion ON ERP.DBO.TranPurchaseOrderDetail
INSTEAD OF UPDATE

AS

IF UPDATE(Quantity)

BEGIN

Update RequisitionSlipDetail
set RequisitionSlipDetail.PoQuantity =

(Select PoQuantity from RequisitionSlipDetail where
ItemCode=(Select CAST(i.ItemCode as nvarchar(20)) from inserted as i)
and
RSlip_No=(Select CAST(i.RSlip_No as int) from inserted as i)
)
-

((Select Quantity from TranPurchaseOrderDetail where Purchase_OrderNo
=
(Select CAST(i.Purchase_OrderNo as nvarchar(20)) from inserted as i))

- (Select CAST(i.Quantity as int) from inserted as i))

where RequisitionSlipDetail.ItemCode = (Select CAST(i.ItemCode as
nvarchar(20)) from inserted as i) and RequisitionSlipDetail.RSlip_No =
(Select CAST(i.RSlip_No as int) from inserted as i)

Update TranPurchaseOrderDetail set
TranPurchaseOrderDetail.Quantity =
(Select CAST(i.Quantity as int) from inserted as i)
where TranPurchaseOrderDetail.Purchase_OrderNo = (Select
CAST(i.Purchase_OrderNo as nvarchar(20)) from inserted as i)
and
TranPurchaseOrderDetail.ItemCode = (Select CAST(i.ItemCode as
nvarchar(20)) from inserted as i)
and
TranPurchaseOrderDetail.PurchaseDetailId =
(Select PurchaseDetailId from TranPurchaseOrderDetail where
Purchase_OrderNo = (Select CAST(i.Purchase_OrderNo as nvarchar(20))
from inserted as i))

END

[Erland Sommarskog]

santoshborfalkar (sa***************@gmail.com) writes:

This is the Trigger which is not working properly during Update, no any
record is going to be updated so pls help.

I am updating the requisition table when any update in quantity in
podetails table

It's very difficult to tell what might be wrong without any knowledge of
your tables or the business rules.

But I noted a few things that appears ood.

CREATE TRIGGER trig_updateRequistion ON ERP.DBO.TranPurchaseOrderDetail
INSTEAD OF UPDATE
AS
IF UPDATE(Quantity)

So if the Quantity columns is not mentioned in the SET clause, then you
will not perform any update at all?

Update RequisitionSlipDetail
set RequisitionSlipDetail.PoQuantity =

(Select PoQuantity from RequisitionSlipDetail where
ItemCode=(Select CAST(i.ItemCode as nvarchar(20)) from inserted as i)

This may work, if only one row at a time is updated, but it will fail
with an error if many rows are updated. Recall that triggers fire once
per statement, not once per row.

Update TranPurchaseOrderDetail set
TranPurchaseOrderDetail.Quantity =
(Select CAST(i.Quantity as int) from inserted as i)
where TranPurchaseOrderDetail.Purchase_OrderNo = (Select
CAST(i.Purchase_OrderNo as nvarchar(20)) from inserted as i)
and
TranPurchaseOrderDetail.ItemCode = (Select CAST(i.ItemCode
as
nvarchar(20)) from inserted as i)
and
TranPurchaseOrderDetail.PurchaseDetailId =
(Select PurchaseDetailId from TranPurchaseOrderDetail where
Purchase_OrderNo = (Select CAST(i.Purchase_OrderNo as nvarchar(20))
from inserted as i))

I don't understand this casting business. Why cast the columns of "inserted"
when they are the same as in the target table? A simplified version of
the above could be:

Update TranPurchaseOrderDetail
set Quantity = i.Quantity
FROM TranPurchaseOrderDetail T
JOIN inserted i ON T.Purchase_OrderNo = i.Purchase_OrderNo
AND T.ItemCode = i.ItemCode
and T.PurchaseDetailId =

(Select PurchaseDetailId from TranPurchaseOrderDetail where
Purchase_OrderNo = (Select CAST(i.Purchase_OrderNo as nvarchar(20))
from inserted as i))

I did not rewrite the last bit, because, frankly, I don't understand what
it's supposed to mean. It just looks strange.

--
Erland Sommarskog, SQL Server MVP, es****@sommarskog.se

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