Itemupdating fires twice
This includes Update, Edit, Cancel, Delete, Insert, New, and Page.
SPSite Data Query | List Vs Library | List Vs Library2 | Content Types | Pages | List Vs Library2 | Power Shell | One reason to prevent events from being raised is to avoid recursion.
Synchronus – Before event that occurs Differences between Sync & Async event handlers are: 1) Synch Event Handler occurs before the event is completed while Asynch occurs after the event is completed.
2) Synch Event Handler is mostly used to stop the event from completion in order to validate few things.
I write function because I have more than one child tables for same parent.
So rather than write deleting code for finding child data with same id and deleting data I write code and pass List and Parent Id to that function.