Bulk Update Email Trigger - sql

Question

I created a update trigger in Microsoft SQL Server that would email me if a date changed in a row.
Similar to this:
IF UPDATE(ColumnName)
BEGIN
DECLARE #columnVal AS DATETIME
SELECT
#columnVal = i.columnName
FROM
inserted i JOIN deleted d on i.RowId= d.RowId;
EXEC msdb.dbo.sp_send_dbmail
#profile_name = 'me',
#recipients = 'me#company.com',
#body = 'blah blah datechange',
#body_format = 'HTML',
#subject = 'subject';
END
it worked fine for a time.
Then I switched over to batch updates and only the first row email is sent out if the date changes on multiple rows. I tried to set up a cursor to roll through the changes but I cannot get it to work, Similar to below:
DECLARE #columnVal AS DATETIME
DECLARE cur CURSOR LOCAL READ_ONLY FAST_FORWARD FOR
SELECT
i.ColumnName
FROM
inserted i JOIN deleted d on i.RowId= d.RowId;
OPEN cur
FETCH NEXT FROM cur INTO #columnVal
WHILE ##FETCH_STATUS = 0
BEGIN
IF UPDATE(ColumnName)
BEGIN
EXEC msdb.dbo.sp_send_dbmail
#profile_name = 'me',
#recipients = 'me#company.com',
#body = 'blah blah datechange',
#body_format = 'HTML',
#subject = 'subject';
END
FETCH NEXT FROM cur INTO #columnVal
END
CLOSE cur
DEALLOCATE cur
Any ideas on how to accomplish this task? Would the Update(ColumnName) function even work properly nested inside a cursor (would it actually tell me if that column was updated for that row?)

Answer 1

A cursor inside a trigger is a very very bad idea.
A trigger should be very lean - it shouldn't do a lot of work! I would recommend to only "take a note" of who you have to send an e-mail to - but leave the actual sending of the e-mail to a separate e.g. SQL Server Agent Job which is not part of the trigger.
Triggers are fired often and often unexpectedly - don't put a log of processing burden into them! And especially not a performance killer like a cursor!
To find those rows that you're interested in, you can use a WHERE clause something like:
WHERE inserted.ColumnName <> deleted.ColumnName
In the context of an UPDATE trigger, this means the new value of ColumnName is different from the old value --> this column has been updated.