MCP SQL Server (Node.js/TypeScript)

A Model Context Protocol (MCP) server for connecting to and querying SQL Server, MySQL, and OceanBase databases, built with TypeScript and Node.js.

What is MCP?

MCP (Model Context Protocol) is an open protocol that allows AI assistants to securely and standardly interact with external data sources and tools. Through MCP servers, AI assistants can:

• Directly connect to databases to execute queries
• Call external APIs to get real-time data
• Access file systems and cloud storage
• Execute custom business logic

MCP architecture contains two core components:

• MCP Client: Built into AI assistants (like Claude Desktop), responsible for communicating with servers
• MCP Server: Independent processes that provide specific tools and data access capabilities

Features

• List all available databases
• List all tables in a specific database
• Get table structure information (columns, data types, primary keys, etc.)
• Execute safe SELECT queries (limited to 1000 rows)
• Get table index information
• Get table statistics (row count, size, etc.)
• Connection pool management for improved performance

Installation

Via npm (Global Installation)

npm install -g @ggball/mcp-database

After global installation, the mcp-database command will be available system-wide.

Via npx (Without Installation)

npx @ggball/mcp-database

From Source

1. System Requirements

• Node.js 18.0.0 or higher
• npm 9.0.0 or higher
• SQL Server (any version)

2. Install Dependencies

npm install

3. Build the Project

npm run build

Configuration

Environment Variables

Create a .env file or set the following environment variables:

Unified Configuration (Recommended)

Use DB_* prefix for a simplified configuration that works with all database types:

| Environment Variable | Description | Default Value | |---------------------|-------------|---------------| | DB_TYPE | Database type: sqlserver, mysql, or oceanbase | sqlserver | | DB_HOST | Server address | localhost | | DB_PORT | Port number (auto-defaults by DB_TYPE) | 1433 / 3306 / 2881 | | DB_USER | Username | root | | DB_PASSWORD | Password | (empty) | | DB_DATABASE | Default database | master | | DB_CHARSET | Character set (MySQL/OceanBase) | utf8mb4 | | DB_ENCRYPT | Enable encryption (SQL Server) | true | | DB_TRUST_SERVER_CERTIFICATE | Trust server certificate (SQL Server) | true | | DB_REQUEST_TIMEOUT | Request timeout in milliseconds | 30000 |

Database-Specific Overrides (Optional)

For advanced scenarios, you can override specific settings for each database type:

| Environment Variable | Description | Default Value | |---------------------|-------------|---------------| | SQLSERVER_HOST | SQL Server host (overrides DB_HOST) | - | | SQLSERVER_PORT | SQL Server port (overrides DB_PORT) | - | | SQLSERVER_USER | SQL Server user (overrides DB_USER) | - | | SQLSERVER_PASSWORD | SQL Server password (overrides DB_PASSWORD) | - | | SQLSERVER_DATABASE | SQL Server database (overrides DB_DATABASE) | - | | SQLSERVER_ENCRYPT | SQL Server encryption (overrides DB_ENCRYPT) | - | | SQLSERVER_TRUST_SERVER_CERTIFICATE | Trust certificate (overrides DB_TRUST_SERVER_CERTIFICATE) | - | | MYSQL_HOST | MySQL host (overrides DB_HOST) | - | | MYSQL_PORT | MySQL port (overrides DB_PORT) | - | | MYSQL_USER | MySQL user (overrides DB_USER) | - | | MYSQL_PASSWORD | MySQL password (overrides DB_PASSWORD) | - | | MYSQL_DATABASE | MySQL database (overrides DB_DATABASE) | - | | MYSQL_CHARSET | MySQL charset (overrides DB_CHARSET) | - | | OCEANBASE_HOST | OceanBase host (overrides DB_HOST) | - | | OCEANBASE_PORT | OceanBase port (overrides DB_PORT) | - | | OCEANBASE_USER | OceanBase user (overrides DB_USER) | - | | OCEANBASE_PASSWORD | OceanBase password (overrides DB_PASSWORD) | - | | OCEANBASE_DATABASE | OceanBase database (overrides DB_DATABASE) | - | | OCEANBASE_CHARSET | OceanBase charset (overrides DB_CHARSET) | - |

Priority: Specific DB env vars (e.g., SQLSERVER_HOST) > Unified DB_* vars > Defaults

Example .env File

Simple Configuration (Single Database)

# SQL Server (default)
DB_TYPE=sqlserver
DB_HOST=localhost
DB_PORT=1433
DB_USER=sa
DB_PASSWORD=YourPassword123
DB_DATABASE=MyDatabase
DB_ENCRYPT=true
DB_TRUST_SERVER_CERTIFICATE=true

MySQL Configuration

DB_TYPE=mysql
DB_HOST=localhost
DB_PORT=3306
DB_USER=root
DB_PASSWORD=YourPassword123
DB_DATABASE=mydb
DB_CHARSET=utf8mb4

OceanBase Configuration

DB_TYPE=oceanbase
DB_HOST=localhost
DB_PORT=2881
DB_USER=root
DB_PASSWORD=YourPassword123
DB_DATABASE=mydb
DB_CHARSET=utf8mb4

Usage

Running the Server

npm start

Or for development with auto-rebuild:

npm run dev

Configuration in Claude Desktop

Config File Location

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

Option 1: Using Global Installation (Recommended)

If you installed the package globally:

{
  "mcpServers": {
    "sqlserver": {
      "command": "mcp-sqlserver",
      "env": {
        "SQLSERVER_HOST": "localhost",
        "SQLSERVER_PORT": "1433",
        "SQLSERVER_USER": "sa",
        "SQLSERVER_PASSWORD": "YourPassword123",
        "SQLSERVER_DATABASE": "MyDatabase"
      }
    }
  }
}

Option 2: Using npx

{
  "mcpServers": {
    "sqlserver": {
      "command": "npx",
      "args": ["@ggball/mcp-database"],
      "env": {
        "SQLSERVER_HOST": "localhost",
        "SQLSERVER_PORT": "1433",
        "SQLSERVER_USER": "sa",
        "SQLSERVER_PASSWORD": "YourPassword123",
        "SQLSERVER_DATABASE": "MyDatabase"
      }
    }
  }
}

Option 3: From Source

{
  "mcpServers": {
    "sqlserver": {
      "command": "node",
      "args": ["/path/to/mcp-sqlserver-npm/dist/index.js"],
      "env": {
        "SQLSERVER_HOST": "localhost",
        "SQLSERVER_PORT": "1433",
        "SQLSERVER_USER": "sa",
        "SQLSERVER_PASSWORD": "YourPassword123",
        "SQLSERVER_DATABASE": "MyDatabase"
      }
    }
  }
}

Restart Claude Desktop after configuration.

Configuration in Claude Code

Config File Location

• macOS/Linux: ~/.config/claude-code/config.json
• Windows: %APPDATA%\claude-code\config.json

Option 1: Using Global Installation (Recommended)

{
  "mcpServers": {
    "sqlserver": {
      "command": "mcp-sqlserver",
      "env": {
        "SQLSERVER_HOST": "localhost",
        "SQLSERVER_PORT": "1433",
        "SQLSERVER_USER": "sa",
        "SQLSERVER_PASSWORD": "YourPassword123",
        "SQLSERVER_DATABASE": "MyDatabase"
      }
    }
  }
}

Option 2: Using npx

{
  "mcpServers": {
    "sqlserver": {
      "command": "npx",
      "args": ["@ggball/mcp-database"],
      "env": {
        "SQLSERVER_HOST": "localhost",
        "SQLSERVER_PORT": "1433",
        "SQLSERVER_USER": "sa",
        "SQLSERVER_PASSWORD": "YourPassword123",
        "SQLSERVER_DATABASE": "MyDatabase"
      }
    }
  }
}

Option 3: From Source

{
  "mcpServers": {
    "sqlserver": {
      "command": "node",
      "args": ["/path/to/mcp-sqlserver-npm/dist/index.js"],
      "env": {
        "SQLSERVER_HOST": "localhost",
        "SQLSERVER_PORT": "1433",
        "SQLSERVER_USER": "sa",
        "SQLSERVER_PASSWORD": "YourPassword123",
        "SQLSERVER_DATABASE": "MyDatabase"
      }
    }
  }
}

Restart Claude Code after configuration.

Available Tools

1. list_databases

Lists all SQL Server databases (excluding system databases).

Tool name: list_databases
Parameters: None

Example:

List all available databases

2. list_tables

Lists all tables in a specific database.

Tool name: list_tables
Parameters:
  - database (required): Database name
  - schema (optional): Schema name, defaults to "dbo"

Example:

List all tables in MyDatabase

3. describe_table

Gets table structure information including columns, data types, nullable, primary keys, etc.

Tool name: describe_table
Parameters:
  - database (required): Database name
  - table (required): Table name
  - schema (optional): Schema name, defaults to "dbo"

Example:

Show the structure of the Users table in MyDatabase

4. execute_query

Executes SQL SELECT queries (only SELECT and WITH allowed, limited to 1000 rows).

Tool name: execute_query
Parameters:
  - query (required): SQL query statement
  - database (optional): Database name, defaults to configured database

Example:

Query users older than 18 from the Users table

5. get_table_indexes

Gets index information for a table.

Tool name: get_table_indexes
Parameters:
  - database (required): Database name
  - table (required): Table name
  - schema (optional): Schema name, defaults to "dbo"

Example:

Get index information for the Users table

6. get_table_stats

Gets table statistics including row count and storage size.

Tool name: get_table_stats
Parameters:
  - database (required): Database name
  - table (required): Table name
  - schema (optional): Schema name, defaults to "dbo"

Example:

Get statistics for the Users table

Usage Examples

Scenario 1: Explore Database

You: List all available databases
Claude: [calls list_databases] ...

You: Show what tables are in MyDatabase
Claude: [calls list_tables] ...

Scenario 2: Query Data

You: Query the last 10 orders from Orders table
Claude: [calls describe_table to understand table structure]
      [calls execute_query to perform query] ...

Scenario 3: Analyze Table Structure

You: Analyze the structure and indexes of Users table
Claude: [calls describe_table]
      [calls get_table_indexes]
      [calls get_table_stats] ...

Security Notes

• execute_query tool only allows SELECT and WITH queries
• Automatically blocks statements containing dangerous keywords (DROP, DELETE, UPDATE, etc.)
• Query results are limited to 1000 rows

Development

Project Structure

mcp-database/
├── src/
│   ├── index.ts       # Main server entry point
│   ├── config.ts      # Configuration management
│   └── connection.ts  # Connection pool implementation
├── dist/              # Compiled output
├── package.json
├── tsconfig.json
└── README.md

Scripts

• npm run build - Compile TypeScript
• npm run dev - Compile and run in development mode
• npm start - Run the compiled server
• npm run watch - Watch mode for TypeScript compilation

Dependencies

• @modelcontextprotocol/sdk - Official MCP SDK for TypeScript
• tedious - SQL Server connector for Node.js
• zod - Schema validation
• dotenv - Environment variable management

License

MIT License

Sources

• MCP TypeScript SDK GitHub
• NPM Package: @modelcontextprotocol/sdk
• GitHub Repository
• 掘金 - MCP TypeScript SDK 核心概念
• Mojotv.cn - MCP TypeScript SDK 教程