In our Application, Process models are chained. User can step back to any node a

In the Process Modeler, open the node that save data to DB, you have to uncheck "Allow users to step back to this node from the next chained activity." in Other tab.
If you only want data to be written once, you can't let user go back to this node.

MNI instance number is the number of instances that will be executed each time the node is activated. So this won't help you.

If you still see the need to let user go back to previous nodes (before the save to DB), you'll have to do the flow navigation based on additional buttons on the UI screen, instead of relying on the Step Back feature. You also need to think about what do you want to do with the data already written, if the user made some changes. Most likely, you'll have to do the update, instead of inserting new row.

Hi komal,
My suggestion is, make a separate workflow using rule event, for database node(s), which is independent of main flow and trigger the rule event using a pv when it required to execute.

@Komalk: Adding to Rahul's suggestion, you just keep user input task and those script where you are not doing any heavy activity in chain and other nodes should in a parallel flow.

Are you only executing the save to database node once to prevent duplicate rows? If so, have you considered using the output on the save node to place the saved values into the pv? That way each time it will just update the saved values.

Hi,
I think the below procedure works:

Have the Save to DB in a subprocess.
In the subprocess, make sure that you use a flag and write a condition that If flag is true, then only run the DB node else DO not perform any task and simply exit the subprocess.
In the main process, for the first time, after the subprocess(Save to DB) is completed, change the flag from true to false.

So whenever the subprocess is called, I think because of the flag ,Save to DB task would not be executed.

@komalk Until and unless there are no heavy database updates which leads to chaining issues, a pretty straight forward as well as simple approach should be as specified by Phil - Use the same PV in the inputs and outputs of Write to Data Store Entity smart service.

Thanks for all good suggestions. implemented pv approach.. it is wrking now.. Thanks again