We are having Office 365 plan E3 with SharePoint Online Plan2. I am trying to avoid using SQL Server as it is hosted in Cloud. There will not be any access to SQL Server or Database. But I have a scenario where I need to display the Cascading Drop downs drived from Database and display the result. For this, I am planning to create an XML file as database and copy that file to the server. Please suggest me a nice to way to achieve this.