SharePoint uses lookup fields to represent the Parent-Child relationship. For child list items it is OK as you can trace back to its parent from the lookup field. For parent the OOB forms are not good enough as they are not displaying the children belong to it. In real world it is often required that when view the parent list item it also displays its children, further more it is great if user can add child list items directly from the parent. In SharePoint on-premise we can use visual web parts and code the parent/child logic and use web part pages to replace the parent item forms. In SharePoint online we can't do server model code and visual web parts, so the solution is almost NO CODE and just a little bit client side scripts, and they work beautifully! Here I will do a step by step demonstration to explain the ideas: Step 1: Create a parent list called "Category" and a child list called "Product", in Product list add a lookup field to reference Cat...
You will find quite a few articles talking and comparing SharePoint online and on premise. I found an interesting post and just copy and paste below: In April 2011, Microsoft launched Office 365 – a comprehensive set of Software as a Service (SaaS) solutions that allow any organization to obtain hosted, cloud-based access to Exchange, Lync, Office Web Applications – and SharePoint Online . All offer guaranteed uptime, fault tolerance, contractual service levels, and clear, predictable pricing. How Do You Choose Between Cloud and On-Premises? Many organizations start by moving email to the cloud. Few organizations have highly customized Exchange email environments. For many, it’s a no-brainer to migrate existing mailboxes to a hosted version of Exchange, because it simplifies the level of infrastructure support for fault tolerance, recovery, web access, border security, and archiving. And, the services and configuration used for Exchange service on premises are usually the ...