If you're doing .Net Core you could also take a look at LiteDB. Use SQL queries in a local (optionally encrypted) file using a single embedded nuget package.

If you're doing .Net Core you could also take a look at LiteDB. Use SQL queries in a local (optionally encrypted) file using a single embedded nuget package. Also creates schemas on the fly when you first persist collection types as per traditional NoSQL systems. I'm using it to create an embeddable out of the box passwordless auth system that has no external dependencies. Works great. Admittedly I've not tried it under extreme load yet, but I'm happy to migrate it onwards if something I create goes massive. (Edit: to be clear it is NoSQL, but you can query it using almost standard SQL which is what I do).