is it possible to run an automation before save?

I suggest that you trigger an Automation to record the Parent summary value upon any add modify delete change to the child records. Then you will always have the complete history. You do not need to record anything in the instant before the save, just record everything after the save and you will have a compete history.

Hi ,

The moment i change the value in detail table , the summary is recalculated . Now the parent has the new summary value. 

Automation will run only after the save. So it is of no use . 

Before the automation triggers , the value in the parent table changes.

Thanks
Pushpakumar

can you please suggest is there any other way possible. I cant use snap shot since it is a formula based field

There is no problem with what I suggested. Just record the value of that summary field in a history table after each edit of the child tables records, What are you seeing as the problem with that solution?

I suggest that you try my solution and then post back if there is a problem.

There are multiple ways to do this with script. Unfortunately I am not going to create a demo as it would be very specific to choices I might make in an implementation and may not map to your situation as your question is rather broad (no table, relationship, field details).

>its urgent , can some one please help

If you need individual assistance feel free to contact me off-world using the information in my profile:

https://getsatisfaction.com/people/dandiebolt