Update Trigger better approach - tsql

Question

I have a Trigger i am developing and want it to basically handle Updates in the sense of the Update statement, not so worried about Delete or Insert statements at the moment.
The end result is that i have two status fields active & inactive, which are bit & datetime respectively. The active field is used to invalidate a record, manually for the time, and i want to make sure that the inactive field contains a value of active change.
Ideally, i would like to check to see if active=0 and place a datetime stamp, using now(), in the field for the record. Long-term im sure i will want to validate that the inactive field doesnt have a datetime stamp already, but for now overriding it fine. As well, would like to have it check if active=1 and clear out the inactive field if any value exists.
The inactive field is nullable so there wont be a conflict.
Trigger Definition, as of now:
CREATE TRIGGER dbo.TRG_tblRegistration_Inactive
ON dbo.tblRegistration
AFTER UPDATE
AS
BEGIN
SET NOCOUNT ON;
IF update(active) BEGIN
update r
set inactive=now()
from tblRegistration r
join inserted i on r.id = i.id
where i.active = 0
END
END
I have a pretty good understanding of the inserted & deleted trigger tables.
Question:
Is there a better logic pattern within the trigger that will get me the ultimate desired goal?
Any considerations to be had if they submit a inactive value with the active=0, or active=1?
Current Form of the Trigger:
ALTER TRIGGER dbo.TRG_tblRegistration_Inactive
ON dbo.tblRegistration
AFTER UPDATE
AS
BEGIN
SET NOCOUNT ON;
IF update(active) BEGIN
update r
set inactive=getdate()
from tblRegistration r
join inserted i on r.id = i.id
where i.active = 0
update r
set inactive=NULL
from tblRegistration r
join inserted i on r.id = i.id
where i.active=1
END
END
It works and does as expected but want to make sure that first there isnt a better way of doing this (at the database side or in the trigger).

Answer 1

I think that it'd be better to change active to a (persisted) computed column, with this definition:
CASE WHEN inactive IS NULL THEN 0 ELSE 1 END
Then you don't need any triggers at all, and you can just set inactive = GETDATE() to accomplish the purpose.
Nonetheless, the way that your trigger is currently written (in both versions), the inactive column is going to be updated to the current date even if I run a query like this:
UPDATE tblRegistration
SET active = 0
WHERE active = 0
If you only want the date to be updated if the field changes from 1 to 0, then your update statement in the trigger would need to be:
UPDATE tblRegistration
SET inactive = GETDATE()
FROM inserted i
INNER JOIN deleted d ON i.id = d.id
WHERE tblRegistration.id = i.id AND i.active = 0 AND d.active = 1