INSERT Trigger not firing an update? - sql

Question

Ok so i have a fairly basic trigger :
In words, After Insert, Get IP information and update the Inserted row with the new data
CREATE TRIGGER [BasicData.IPInfo.Gather]
ON [BasicData]
AFTER INSERT
AS
BEGIN
DECLARE #City VARCHAR(1000),
#Country VARCHAR(1000),
#IP VARCHAR(1000),
#ROWID UNIQUEIDENTIFIER
SELECT #IP=[IP],#ROWID=[ID] FROM [inserted]
SELECT #Country = [Country], #City= [City]
FROM [IPInfo] WHERE [IP] = #IP
IF (#City IS NOT NULL) AND (#Country IS NOT NULL)
BEGIN -- Never seems to fire
UPDATE [BasicData]
SET [IPCountry]=#Country,[IPCity]=#City
WHERE [ID] = #ROWID
END
ELSE
BEGIN -- Fired correctly
INSERT INTO [IPInfo.Missing] VALUES (#IP)
END
END
Now the problem is, It adds the missing IP information correctly (Only when missing), however, it does not seem to ever update the table when it does, What am i missing?
Ive tweaked it in every possible way i could think of... (My trigger knowledge is rather bad)

Answer 1

There are a few problems:
INSERTED can contain many rows. Your trigger allows for only one.
The trigger is AFTER INSERT, and I guess this might exclude UPDATEs. Try AFTER INSERT, UPDATE
Your IF statement isn't checking for an UPDATE - what if the column is UPDATED to NULL? it won't catch it even though it was an update. What if something inserted NON NULL data? it will think it was an UPDATE.
As far as I know the only way to identify an UPDATE is to join INSERTED and `DELETED on the PK. If there is a match, it's been updated.
Perhaps you could rewrite it like this:
CREATE TRIGGER [BasicData.IPInfo.Gather]
ON [BasicData]
AFTER INSERT, UPDATE
AS
BEGIN
-- Save UPDATES to BasicData
UPDATE [BasicData]
SET [IPCountry]=I.Country,[IPCity]=I.City
FROM [BasicData] UT
INNER JOIN
[inserted] I
ON I.ID = UT.ID
INNER JOIN
Deleted D
ON D.ID = I.ID
INNER JOIN
[IPInfo] IP
ON I.ID = IP.ID
-- Save inserts to Missing
INSERT INTO [IPInfo.Missing] (IP)
SELECT IP FROM
INSERTED I
WHERE NOT EXISTS (SELECT 1 FROM DELETED D WHERE D.ID = I.ID)
END