Update a list item in a list in a root site from a sub site

Question

I am currently working on SharePoint 2016 on premises,

I have a situation where in the root site, I have a list A which has a content type X and one of the fields is counter (starts with 1). From a sub-site there is another list B, which has a lookup to List A, when a user creates an item on list B the counter related to the item in List A should be updated. I am trying to see the different options I have. The problem is I cannot use provider hosted apps since it is against policies so no event receivers can be created via server side code.

I was thinking of doing this via workflow via SPD, can anyone tell me if this is a good idea, and if yes provide me with some knowledge on this since I have never done any workflows before.

Answer 1

1. One way I see is you can customize your subsite list B forms.

   In that you will add your script and update items of root site list A items.

   Script will have PreSaveAction method which will be called when you add/update item.

   Inside that method you can get item from the root site list A and update its value as per your need.

   Look here for code snippets for How to: Create, Update, and Delete List Items Using JavaScript

2. The other way you could use is workflow. Here is the steps to Create a workflow for SharePoint.

   Once you are able to create workflow you can see here for more info about How you can update list item in worklfow.

   Also check this link: How to make workflow update another list item based on a calculation.

In my opinion I would prefer first option. But you can go ahead with any you would like as both options are good to go. There might be other ways also available but I feel this are two best options for you.

Hope this helps!