MSSQL Trigger - Updating newly inserted record on INSERT

Question

I wish to make a modification (Set Deleted = 1) to rows being inserted into my table CustomerContact if the SELECT statement returns more than 0.

I have the following, but it remains untested:

CREATE TRIGGER mark_cust_contact_deleted ON CustomerContact
AFTER INSERT AS
BEGIN
DECLARE @numrows INT;

    /* Determine if order matches criteria for marking customer contact as DELETED immediately */
    SELECT @numrows = COUNT(*)
    FROM [Order] o
    JOIN OrderMeterDetail om
          ON o.OrderID = om.OrderID
    WHERE o.WorkTypeID = 3 AND o.WorkActionID = 26 AND o.WorkStageID IN (109, 309, 409)
    AND om.MeterDetailTypeID = 1 AND om.MeterLocationID IN (2, 4)
    AND o.orderid IN (SELECT OrderID FROM INSERTED);

    /* If the order matches the criteria, mark the customer contact as deleted */
    IF (@numrows >= 1)

        UPDATE CustomerContact
        SET Deleted = 1
        WHERE CustomerContactID IN (SELECT CustomerContactID FROM INSERTED);

END

Within my IF statement, I am using FROM INSERTED, assuming that this will return the newly inserted id for the record that was created by the insert.

I have two questions about this statement:

• Will this part of the statement perform an UPDATE just the record that was just inserted into CustomerContact?

  UPDATE CustomerContact SET Deleted = 1 WHERE CustomerContactID IN (SELECT CustomerContactID FROM INSERTED);

• Is this the way that would be deemed correct to make a change to a row that has just been inserted based on the result of a SELECT statement?

CustomerContactID is an auto-incrementing primary key column.

Answer 1

You say "Just the record that was inserted". Inserted can contain more than one record. If there is only one, then your trigger will function as you expect. But if there is more than one, it won't.

I would rewrite your logic into a single update statement along the lines of...

 Update CustomerContact
 Set Deleted = 1
 From CustomerContact
       inner join inserted on CustomerContact.CustomerContactID = inserted.CustomerContactID
       inner join orders on inserted.OrderID = orders.OrderID
 where
     -- some criteria.

Answer 2

CREATE TRIGGER mark_cust_contact_deleted ON CustomerContact
AFTER INSERT AS
BEGIN
DECLARE @numrows INT;

    /* Determine if order matches criteria for marking customer contact as DELETED immediately */
    -- Get all the records into a temp table 
    SELECT * INTO #Temp
    FROM inserted
    Declare @ID int;

    SELECT @numrows = COUNT(*)
    FROM [Order] o
    JOIN OrderMeterDetail om
          ON o.OrderID = om.OrderID
    WHERE o.WorkTypeID = 3 AND o.WorkActionID = 26 AND o.WorkStageID IN (109, 309, 409)
    AND om.MeterDetailTypeID = 1 AND om.MeterLocationID IN (2, 4)
    AND o.orderid IN (SELECT OrderID FROM #Temp);
 IF (@numrows >= 1)
  BEGIN
    WHILE EXISTS (SELECT TOP 1 * FROM #Temp)
    BEGIN

    SELECT TOP 1 @ID = ID FROM #Temp


    /* If the order matches the criteria, mark the customer contact as deleted */


        UPDATE CustomerContact
        SET Deleted = 1
        WHERE CustomerContactID IN (SELECT CustomerContactID FROM #Temp WHERE ID = @ID);

        DELETE FROM #Temp WHERE ID = @ID
    END
  END   
     DROP TABLE #Temp
END

I think you can do something like this, tweak the code to futher suit for needs, hope this will help.

Answer 3

Here is the final solution that I used to solve this issue:

CREATE TRIGGER mark_cust_contact_deleted ON CustomerContact
AFTER INSERT AS
BEGIN

    UPDATE CustomerContact
    SET Deleted = 1
    FROM CustomerContact cc
        JOIN inserted i
            ON cc.CustomerContactID = i.CustomerContactID
        JOIN [Order] o
            ON i.OrderID = o.OrderID
        JOIN OrderMeterDetail om
            ON i.OrderID = om.OrderID
    WHERE o.WorkTypeID = 3 AND o.WorkActionID = 26 AND o.WorkStageID IN (109, 309, 409)
    AND om.MeterDetailTypeID = 1 AND om.MeterLocationID IN (2, 4)

END