I am setting up quite a large system with multiple servers (MS SQL Server), and Office 365 Access DB, and a custom SharePoint web app for reporting purposes.
The system should work as follows:
Each location has a singular server that stores information pertaining to that business instance. A client application allows insert/update/delete operations through a GUI for the business, and manipulates the server database (running MS SQL Server).
Each location's database is replicated (one way) to the cloud (MS Office 365 which uses Azure), so that all of the different locations information can be accessed from the web.
A custom web app can then query the cloud database and produce reports (mainly charts for analysis). This app will only have read permissions on the data - no modification will happen at this end.
My question is if and how I can replicate the separate servers to the cloud. As far as I understand, Microsoft's web apps platform can tie an application to only a single database.
Does this mean that I must replicate all of the databases to a singular, all-encompassing database on the cloud? Is this possible? For manageability reasons, it would be great to mirror each local database to a matching database on the cloud, and then somehow aggregate these cloud databases into a singular one for the web app to access. Could this be done through sharding / partitioning?
Am I correct in saying that even custom written web-apps can access only one database through this system? If I am incorrect, how hard is it to tie an app into multiple databases?
Sorry, I am fairly inexperienced in this field and will really appreciate any guidance!