I figured this mailing list would be interested. I have just finally published two packages what I've been working on for a bit that provide access to Calcite on .NET:
https://www.nuget.org/packages/Apache.Calcite.Data Apache.Calcite.Data provides an ADO.NET database driver (provider) for Apache Calcite. It functions mostly like the current Calcite JDBC connection. You can set up your model the same way you can in JDBC. https://www.nuget.org/packages/Apache.Calcite.Adapter.AdoNet Apache.Calcite.Adapter.AdoNet provides the other half. A Calcite adapter for ADO.NET. Pretty much like the JDBC adapter. You can add it to your schema model on the driver and wrap other ADO.NET connections. https://github.com/ikvmnet/calcite-dotnet Together, these let you do on .NET what you can do with the JDBC driver and JDBC adapter in Calcite itself, without JDBC. So, you can make use of the native SQL or Npgsql or Sqlite .NET drivers. These are but two foundational pieces I've been working on towards my ultimate goal: an Entity Framework provider for Calcite and an Entity Framework Adapter for Calcite. Those are under heavy development still. Though I do sorta/kinda have them working. The end goal will be to allow you to reshape existing database or EF Core database contexts and then export those to APIs using tools like GraphQL (Hot Chocolate) or JSON API. In .NET land it is very easy to take an EF Core context and publish it on GraphQL. Automatically generating all the GraphQL stuff. Which is great, except you rarely want an exact 1:1 copy of your database model as your API. Hence Calcite. https://github.com/ikvmnet/calcite-efcore
