@tsolarin , like i mentioned in my topic above, I'm developing an open-source (APL 2.0) SQL-99 database system, entirely written in .NET, named DeveelDB.
Historically, but also practically, all the SQL systems provide a command-line client for interacting with the system.
SQL is not a simple language and might contain complex commands, multi-line procedures, etc. that adds complexity to the implementation of the client, since the user would have a terrible experience by not be able to write the code in a fluent way.
In Java world this problem was tackle down by projects like HenPlus or SQLine, which use the GNU ReadLine implementation for Java.
I tried to emulate this, many years ago, by writing my own library (named Deveel ReadLine), but I decided that I didn't want to focus on that, since the SQL engine itself is a huge project.
Also, to ehnanche the experience I want to provide an auto-complete support for object names (eg. table name, trigger names, schema names, etc.) and possibly also the language elements.
The idea is to come out with a sort of SQL-REPL for .NET, specifically oriented to DeveelDB.