Insert Trigger Question

Can someone help me with this scenario:
I have 2 tables one detail and one summary. The key fields for betwen the the detail and summary tables are the date field na the part # field.
I need to create a trigger that will insert records when they do not exist in the summary table and also only update the records that are needing to be modified. Any Ideas?

ThanksReal time warehousing?

Can't you run a scheduled process instead?|||Originally posted by Brett Kaiser
Real time warehousing?

Can't you run a scheduled process instead?

I need to have this summary infomration available at any time the daily reports need to be run. A scheduled process would be easier but I need to keep this table up to date as transcations are processed in the detail table.|||Use this as an example:

create table item(id int identity,item# varchar(10))
create table itemsummary(id int identity,item# varchar(10),quantity int)
go
create trigger iu_item on item
for insert,update
as
insert itemsummary(item#)
select item# from inserted i
where not exists(select 1 from itemsummary where item#=i.item#)
update itemsummary set quantity=(select count(*) from item i where i.item#=itemsummary.item#)
go
insert item(item#) values('#1')
insert item(item#) values('#1')
insert item(item#) values('#2')

select * from item
select * from itemsummary|||He'll need to update..the count? for the part#

So you need 2 sections...

Check

-- An Update
IF EXISTS (SELECT * FROM inserted) AND EXISTS (SELECT * FROM deleted)

--An INSERT
IF EXISTS (SELECT * FROM inserted) AND NOT EXISTS (SELECT * FROM deleted)

Then do your apporpriate action...

What's the transaction level?sql