How to update calendar item created by an other list?

Question

Appreciate any thoughts on this:

1. A user edits an existing list item to pick a date to select a project deadline.
2. A custom workflow, initiated by that item change, takes that date and project title from the project list and creates an 'all-day' event on the team calendar. The project title becomes the event title.

Works great, as far as it goes. BUT, obviously, if the project is rescheduled, and a user edits the project list item so that another deadline date is picked, another second event is added to the calendar. But the first event remains.

How can workflows be arranged so that the calendar is updated when an existing deadline in a project list item is changed to a new date?

Thank you!

Answer 1

You need to add a column to the first calendar that stores a unique key of any related item in the team calendar. You could use the SharePoint ID of the first calendar, for example. Add a column to the Team calendar called "ParentID". Let the workflow find an item with that ParentID = current Item ID in the Team calendar. If that item is found, the workflow updates it. If that item is not found, the workflow will create it and write the current item's ID into the ParentID field.

Answer 2

If you some way to identify the item in the calendar (if the project title is unique, or you have some other primary key) then:

you can create a hidden field called 'EventCreated' or something then inside your workflow have a condition that checks if an event is created if it was then run an update list item query on your unique value (see: http://www.documentmanagementworkflowinfo.com/workflow/use-update-list-item-action-sharepoint-designer-workflow.htm)

and if not, then create the event on the calendar and flip EventCreated to Yes