# mcp-server-database

An MCP (Model Context Protocol) server that provides tools for interacting with relational databases. Supports PostgreSQL, MySQL, and SQLite.

## Architecture

```mermaid
graph TB
    subgraph Client
        style Client fill:#4A90D9,stroke:#2E6BA6,color:#FFFFFF
        MCP_Client["MCP Client"]
    end

    subgraph Server["mcp-server-database"]
        style Server fill:#2ECC71,stroke:#1A9B52,color:#FFFFFF
        Index["index.ts<br/>MCP Server Entry"]
        subgraph Tools
            style Tools fill:#F39C12,stroke:#C67D0A,color:#FFFFFF
            T1["query"]
            T2["list_tables"]
            T3["describe_table"]
            T4["list_databases"]
            T5["execute_migration"]
            T6["get_schema"]
        end
    end

    subgraph Databases["Database Engines"]
        style Databases fill:#9B59B6,stroke:#7D3C98,color:#FFFFFF
        PG["PostgreSQL"]
        MY["MySQL"]
        SQ["SQLite"]
    end

    MCP_Client -- "stdio transport" --> Index
    Index --> T1 & T2 & T3 & T4 & T5 & T6
    T1 --> PG & MY & SQ
    T2 --> PG & MY & SQ
    T3 --> PG & MY & SQ
    T4 --> PG & MY
    T5 --> PG & MY & SQ
    T6 --> PG & MY & SQ
```

## Installation

```bash
npm install
npm run build
```

## Configuration

| Variable | Description | Required |
|---|---|---|
| `DB_DRIVER` | Database driver: `postgres`, `mysql`, or `sqlite` | Yes |
| `DB_HOST` | Database host | Yes (postgres/mysql) |
| `DB_PORT` | Database port | No |
| `DB_USER` | Database username | Yes (postgres/mysql) |
| `DB_PASSWORD` | Database password | Yes (postgres/mysql) |
| `DB_NAME` | Database name | Yes |
| `DB_PATH` | Path to SQLite file | Yes (sqlite) |

## Usage

### Standalone

```bash
DB_DRIVER=postgres DB_HOST=localhost DB_USER=admin DB_PASSWORD=secret DB_NAME=mydb npm start
```

### Development

```bash
npm run dev
```

### Docker

```bash
docker build -t mcp-server-database .
docker run -e DB_DRIVER=postgres -e DB_HOST=host.docker.internal -e DB_USER=admin -e DB_PASSWORD=secret -e DB_NAME=mydb mcp-server-database
```

### MCP Client Configuration

```json
{
  "mcpServers": {
    "database": {
      "command": "node",
      "args": ["dist/index.js"],
      "env": {
        "DB_DRIVER": "postgres",
        "DB_HOST": "localhost",
        "DB_PORT": "5432",
        "DB_USER": "admin",
        "DB_PASSWORD": "secret",
        "DB_NAME": "mydb"
      }
    }
  }
}
```

## Tool Reference

| Tool | Description | Parameters |
|---|---|---|
| `query` | Execute a SQL query | `sql`, `params?` |
| `list_tables` | List all tables | none |
| `describe_table` | Describe a table schema | `table_name` |
| `list_databases` | List databases on the server | none |
| `execute_migration` | Execute a migration SQL script | `sql` |
| `get_schema` | Get full database schema DDL | none |

## License

MIT