Assistance creating my first trigger

I hope you guys can help. I am looking to create a trigger that watches for
updates to the sch_status column and fires when the update changes the value
to 4. The code that will be executed is below with addition of some code to
e-mail the results. It is the actual code to create the update trigger on the
schedule table I need some help with.
select s.sch_id,
'Date Scheduled'=convert(varchar(17),s.sch_date,113),
s.e_subject,
'Number Processed'=(select count(dl.sch_id) from distribution_list dl where
dl.sch_id = s.sch_id and dl.delivery_status=2),
'Total Number'=(select count(dl.sch_id) from distribution_list dl where
dl.sch_id = s.sch_id),
'Log file'= '\\Renown\eNewsletters\Logs\SE\'+
convert(varchar(12),getdate(),112) +'.log'
from schedule s
where s.sch_status = 4
order by s.sch_id
Hi
All what you have to do it join the virtual table INSERTED in your query on
the primary key.
It is not recommended that you send e-mails from within a trigger, as it
hurts performance, has horrible consequences with locking and blocking, and
if the e-mail sending fails, your update will get rolled back (and you might
have sent e-mails to 1/2 your customer base). Rather write a record into a
queue type table where another process comes along a sends the e-mails.
Books On Line has some good examples on CREATE TRIGGER and how to use the
virtual tables INSERTED and DELETED.
Regards
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"Russell" <Russell@.discussions.microsoft.com> wrote in message
news:746A52BB-B25C-4EA7-99B9-65574C6171C3@.microsoft.com...
> I hope you guys can help. I am looking to create a trigger that watches
for
> updates to the sch_status column and fires when the update changes the
value
> to 4. The code that will be executed is below with addition of some code
to
> e-mail the results. It is the actual code to create the update trigger on
the
> schedule table I need some help with.
> select s.sch_id,
> 'Date Scheduled'=convert(varchar(17),s.sch_date,113),
> s.e_subject,
> 'Number Processed'=(select count(dl.sch_id) from distribution_list dl
where
> dl.sch_id = s.sch_id and dl.delivery_status=2),
> 'Total Number'=(select count(dl.sch_id) from distribution_list dl where
> dl.sch_id = s.sch_id),
> 'Log file'= '\\Renown\eNewsletters\Logs\SE\'+
> convert(varchar(12),getdate(),112) +'.log'
> from schedule s
> where s.sch_status = 4
> order by s.sch_id
|||In case it leads to a different outcome I plan to have the select statement
and the e-mail (not sql mail) in a stored procedure and have it called by the
trigger.
"Mike Epprecht (SQL MVP)" wrote:

> Hi
> All what you have to do it join the virtual table INSERTED in your query on
> the primary key.
> It is not recommended that you send e-mails from within a trigger, as it
> hurts performance, has horrible consequences with locking and blocking, and
> if the e-mail sending fails, your update will get rolled back (and you might
> have sent e-mails to 1/2 your customer base). Rather write a record into a
> queue type table where another process comes along a sends the e-mails.
> Books On Line has some good examples on CREATE TRIGGER and how to use the
> virtual tables INSERTED and DELETED.
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "Russell" <Russell@.discussions.microsoft.com> wrote in message
> news:746A52BB-B25C-4EA7-99B9-65574C6171C3@.microsoft.com...
> for
> value
> to
> the
> where
>
>
|||You still have the same issues (concurrency/performance), even if you
execute a proc in order to send email from the trigger. I suggest you heed
Mike's suggestion and employ a queue-type table so that you can send the
actual email asynchronously. It's fairly simple to implement.
Hope this helps.
Dan Guzman
SQL Server MVP
"Russell" <Russell@.discussions.microsoft.com> wrote in message
news:47D97573-D64B-4E22-90D7-7B7F1F70404C@.microsoft.com...[vbcol=seagreen]
> In case it leads to a different outcome I plan to have the select
> statement
> and the e-mail (not sql mail) in a stored procedure and have it called by
> the
> trigger.
> "Mike Epprecht (SQL MVP)" wrote:
|||Another possibility is to have a SQL Agent job set up to execute your stored
procedure. This does not mean you need to use SQL Agent mail--the stored
procedure can still call xp_sendmail directly--however, you can have the
trigger fire off msdb.sp_startjob. The execution of this stored procedure
circumvents some of the concurrency/consistency issues in that it makes the
call to launch the process but runs the job synchronously.
If there is a problem with starting the job execution, you will get a
failure notice and your transaction will rollback but you would not have
emailed anyone yet.
Sincerely,
Anthony Thomas
"Dan Guzman" wrote:

> You still have the same issues (concurrency/performance), even if you
> execute a proc in order to send email from the trigger. I suggest you heed
> Mike's suggestion and employ a queue-type table so that you can send the
> actual email asynchronously. It's fairly simple to implement.
> --
> Hope this helps.
> Dan Guzman
> SQL Server MVP
> "Russell" <Russell@.discussions.microsoft.com> wrote in message
> news:47D97573-D64B-4E22-90D7-7B7F1F70404C@.microsoft.com...
>
>
|||In reviewing this thread, I see we forgot to mention that the proc/script to
actually send the email can be asynchronously scheduled with a SQL Agent
job. Thanks for pointing that out.

> If there is a problem with starting the job execution, you will get a
> failure notice and your transaction will rollback but you would not have
> emailed anyone yet.
If Russel doesn't want a sp_startjob failure to rollback the insertion, the
job can be scheduled to run periodically rather than on demand.
Another method is to create a startup proc that runs continuously with a
WAITFOR DELAY loop.
Hope this helps.
Dan Guzman
SQL Server MVP
"AnthonyThomas" <AnthonyThomas@.discussions.microsoft.com> wrote in message
news:948EC3BF-AB7C-4669-BC74-AD81E2E0C71C@.microsoft.com...[vbcol=seagreen]
> Another possibility is to have a SQL Agent job set up to execute your
> stored
> procedure. This does not mean you need to use SQL Agent mail--the stored
> procedure can still call xp_sendmail directly--however, you can have the
> trigger fire off msdb.sp_startjob. The execution of this stored procedure
> circumvents some of the concurrency/consistency issues in that it makes
> the
> call to launch the process but runs the job synchronously.
> If there is a problem with starting the job execution, you will get a
> failure notice and your transaction will rollback but you would not have
> emailed anyone yet.
> Sincerely,
>
> Anthony Thomas
>
> "Dan Guzman" wrote: