ThomasB98/MCPDataBaseServer

MCPDataBaseMSSQLServer

A small, self-contained .NET 8 console application that hosts a Model-Context-Protocol (MCP) server able to talk to a relational database.
Although the project name references MSSQL, the code has been abstracted so you can easily switch between several popular database engines (SQLite, SQL Server, PostgreSQL and MySQL) just by changing the configuration file – no code changes required.

What the project does

1. Bootstraps an MCP server – The Program.cs entry point wires the MCP services and exposes them over STDIO so the executable can be embedded in other host processes (e.g. editors).
2. Initialises a database connection – At start-up the application reads appsettings.json to decide which ADO.NET provider to use and opens the connection (SqliteConnection, SqlConnection, NpgsqlConnection or MySqlConnection).
3. Provides basic logging & validation – Logging is enabled via Microsoft.Extensions.Logging and optional query-validation rules are read from configuration.
4. Offers a playground for experimenting with Dapper & MCP – Because it is framework-agnostic you can point the same binary at different database back-ends to test behaviour and performance.

Quick start

Prerequisites

• .NET 8 SDK (download from https://dotnet.microsoft.com)
• One of the supported databases running locally (or reachable via network)

Build & run

# Restore packages & compile
$ dotnet build

# Run with default settings (SQLite / sample.db)
$ dotnet run --project MCPDataBaseMSSQLServer.csproj

When the application starts you should see logging similar to:

info: Program[0]
      Initializing SQLITE database connection
info: Program[0]
      Database connection established successfully

Changing the database provider

All runtime behaviour is driven by appsettings.json (or the environment-specific variant such as appsettings.Development.json).

"DatabaseSettings": {
  "Provider": "SQLite",        // <-- Change to SQLServer | PostgreSQL | MySQL
  "CommandTimeout": 30,
  "MaxRetryAttempts": 3
},
"ConnectionStrings": {
  "DefaultConnection": "Data Source=sample.db",
  "SqlServerConnection": "Server=localhost;Database=TestDB;Trusted_Connection=true;TrustServerCertificate=true;",
  "PostgreSqlConnection": "Host=localhost;Database=testdb;Username=postgres;Password=password;",
  "MySqlConnection": "Server=localhost;Database=testdb;Uid=root;Pwd=password;"
}

Steps:

1. Set DatabaseSettings:Provider to the desired engine.
2. Update the matching connection string.
3. Re-run the application.

NOTE: The application opens the connection at start-up. If the string is invalid or the server cannot be reached it will throw immediately.

Security & query validation

The Security section allows you to restrict what the MCP server may execute:

"Security": {
  "AllowedCommands": [ "SELECT", "INSERT", "UPDATE", "DELETE" ],
  "RestrictedTables": [ "sys_users", "admin_settings" ],
  "EnableQueryValidation": true
}

• AllowedCommands – Whitelist of SQL verbs permitted.
• RestrictedTables – Blacklist of tables that must never be referenced.
• EnableQueryValidation – Toggle validation on/off.

Adjust these lists to fit the policies of your environment.

Typical changes you may need to make

1. Connection strings – Point to your own databases.
2. Provider selection – Change from the default SQLite to your chosen engine.
3. Timeouts & retry logic – Tune CommandTimeout and MaxRetryAttempts based on workload.
4. Logging level – Set Logging.LogLevel.* to control verbosity.
5. Security rules – Expand or tighten the Security section.
6. Packaging – If you want a single-file executable run:

   dotnet publish -c Release -r win-x64 --self-contained true /p:PublishSingleFile=true
   

Project structure

│   Program.cs               # Bootstrap & composition root
│   appsettings.json         # Main configuration file
│   MCPDataBaseMSSQLServer.csproj
└───README.md                # You are here

Contributing

Pull requests are welcome! If you have feature requests or run into problems, please open an issue.

License

This project is released under the MIT License.