I've got some desktop experience, but am (brand) new to web programming. I've built a well-received C# WPF desktop app that stores data in a local (on user's desktop) SqlLite DB. I'd like to transition the app to remote data storage, probably with a MS SQL Server DB, hosted by a web-host service provider. One database there would hold all the various users data, access controlled by their own username/password.
In fact I've already done that as an experiment, and it functions. My concern is security: at the moment my in-code connection string just uses my db account/password. I'm not such a newb to know that's not a good idea. There must be a standard way to move that private information out of the code and into a sort of relay between the app code and the db. But I don't know the terminology, or what to ask for, despite a day of googling. So:
(1) User requests data save, say
(2) App sends SQL statement and user credentials to relay.
(3) Relay checks credentials against db records (using my db credentials, but that's ok, they're at least not stored in the apps's source code)
(4) Assuming ok, forward sql statement to db.
Is (something like) this a thing? What's it called? Or is there some other standard way to achieve the goal of keep my connection string completely out of the code? Where do I begin reading about how to implement it? How would I know if my web-host would support such a thing?