Hi, I'm a software and database designer/developer with more than 35 years of experience. The past 20 years I was full-time employed (in-situ) by two international organizations; IATTC (San Diego, CA), and the Food and Agriculture Organization (FAO) of the United Nations (Victoria, Seychelles). I'm currently retired, and trying to stay busy, and up-to-date, doing some freelancing, so I have enough free time to dedicate to your project.
I have extensive experience with MS SQL Server (Transact SQL), Oracle's 11g Server (PL/SQL), Firebird, PostgreSQL, and mySQL, and familiarity with many other DBMSs.
I also have extensive knowledge and experience developing desktop/web applications and services with the .net framework, including REST and WCF APIs.
I can teach you how to write services in C# and the .NET framework, since I have done a fair amount of them. To start, your services should not include a user interface, that's a terrible practice that will generate many eventual problems. Instead, settings for your services should be in a initiation file or can be set through an external UI that connects to the service through a protocol (e.g. WCF).
If you think you may be interested in my services, please send me PM. This way I can provide the answer to your test question, share my CV with you (for you to check references and experience), and we can further discuss the details of your requirements.
Best regards,
Marco Garcia