Question

So it’s my understanding that looping and cursors should be avoided unless absolutely necessary. In my situation it seems to me that if I have to rely on them I am doing it wrong so I’d like the communities input.

I am writing a stored procedure to add items to a queue, the number of items added are dependent on the intervals setup for the item type. Once the data is inserted into the queue I need to add the ID’s of the queue items to other tables. I am running into an issue here as I generally rely on SCOPE_IDENTITY() to pull the ID for return.

Below is my table structure:

CREATE TABLE QueueItem (
    QueueItemID [int] IDENTITY NOT NULL,
    ReferenceID [int] NOT NULL,
    StartDate [datetime] NOT NULL
);

CREATE TABLE CatalogDate (
    ReferenceID [int] NOT NULL,
    CatalogID [int] NOT NULL,
    DayCount [int] NOT NULL
);

CREATE TABLE ItemInterval (
    ReferenceID [int] NOT NULL,
    Interval [int] NOT NULL
);


CREATE PROCEDURE SetQueueItem
    @ReferenceID [int],
    @UserID [int]
AS
BEGIN

    DECLARE @DayCount [int]
    DECLARE @CatalogID [int]
    DECLARE @QueueItemID [int]

    SELECT @DayCount = DayCount, @CatalogID = CatalogID
    FROM CatalogDate
    WHERE ReferenceID = @ReferenceID

    DECLARE @Date [datetime] = --SELECT Date from another table using @UserID and @CatalogID

    DECLARE @StartDate [datetime] = (SELECT DATEADD(dd, @DayCount, @Date))

    INSERT INTO QueueItem(ReferenceID, StartDate)
    SELECT @ReferenceID, DATEADD(@DateCount-Interval), @Date)
    FROM ItemInterval
    WHERE ReferenceID = @ReferenceID --SELECT RETURNS MULTIPLE ROWS

Now once the insert of multiple records has been done I need to take the QueueItemID‘s that were generated from the inserts and insert them along with some additional data in two other tables.

The only ways I can see of accomplishing this is by either breaking up the INSERT to loop through each record in ItemInterval and insert them one at a time, or to query the MAX records from the QueueItem table before and after the insert and then loop through the difference assuming the ID’s are perfectly sequential.

Thoughts?

Answer 1

Thanks to @StarShip3000 for the references on OUTPUT

To solve this problem I dumped the results into a variable table using OUTPUT and then use that table to insert the results in the other tables.

DECLARE @QueueItemTable TABLE
(
    ItemID [int]
)

INSERT QueueItem(ReferenceID, StartDate)
OUTPUT inserted.QueueItemID INTO @QueueItemTable(ItemID)
SELECT @ReferenceID, DATEADD(@DateCount-Interval), @Date)
FROM ItemInterval
WHERE ReferenceID = @ReferenceID --INSERTS IDENTITIES into @QueueItemTable variable

--Insert into other tables

INSERT QueueRelationship(QueueItemID)
SELECT ItemID
FROM @QueueItemTable

Viola!