┌──────────────────┐         ┌─────────────────────────┐         ┌──────────────┐
│   AI Assistant    │   MCP   │   Database Explorer     │   SQL   │   Database   │
│                   │◄───────►│   MCP Server            │◄───────►│              │
│  Claude Desktop   │  JSON   │                         │         │  PostgreSQL  │
│  Cursor           │  over   │  • Explores schemas     │         │  MySQL       │
│  VS Code Copilot  │  stdio  │  • Runs queries         │         │  SQLite      │
│  Windsurf         │         │  • Generates ERDs       │         │  MongoDB     │
│  Any MCP client   │         │  • Suggests indexes     │         │              │
└──────────────────┘         └─────────────────────────┘         └──────────────┘

git clone https://github.com/nandanosql/database-explorer-mcp.git
cd database-explorer-mcp
npm install
npm run build

{
  "mcpServers": {
    "database-explorer": {
      "command": "node",
      "args": ["/FULL/PATH/TO/database-explorer-mcp/build/index.js"],
      "env": {
        "DB_EXPLORER_READONLY": "true"
      }
    }
  }
}

{
  "mcpServers": {
    "database-explorer": {
      "command": "node",
      "args": ["/FULL/PATH/TO/database-explorer-mcp/build/index.js"]
    }
  }
}

{
  "servers": {
    "database-explorer": {
      "command": "node",
      "args": ["/FULL/PATH/TO/database-explorer-mcp/build/index.js"]
    }
  }
}

{
  "mcpServers": {
    "database-explorer": {
      "command": "node",
      "args": ["/FULL/PATH/TO/database-explorer-mcp/build/index.js"]
    }
  }
}

# The server reads from stdin and writes to stdout
node /path/to/database-explorer-mcp/build/index.js

npx @modelcontextprotocol/inspector node build/index.js

You: Connect to my PostgreSQL database at localhost, database 'myapp', user 'admin', password 'secret'

AI: ✅ Connected to postgresql database "myapp" with alias "default"

You: What tables are in this database?

AI: Database: myapp (postgresql)
──────────────────────────────────────────────────
  • users  [table]  —  12,450 rows  —  4.2 MB
  • orders  [table]  —  89,120 rows  —  28.7 MB
  • products  [table]  —  2,340 rows  —  1.1 MB
  ...

You: Show me the top 5 customers by total order value

AI: [runs the query automatically]
customer_name │ total_orders │ total_value
──────────────┼──────────────┼────────────
Alice Johnson │ 47           │ $12,450.00
Bob Smith     │ 38           │ $9,870.50
...

You: Generate an ER diagram of the database

AI: [returns Mermaid diagram]

erDiagram
    users {
        int id PK
        varchar username "NOT NULL"
        varchar email "NOT NULL"
    }
    orders {
        int id PK
        int user_id FK
        decimal total_amount "NOT NULL"
    }
    users ||--o{ orders : "user_id"

You: Find any mentions of "alice" across all tables

AI: 🔍 Search results for "alice":
══════════════════════════════════════════════════

📋 users.username — 1 match(es)
  → id: 1 | username: alice | email: alice@example.com

📋 users.email — 1 match(es)
  → id: 1 | username: alice | email: alice@example.com

You: Connect to the SQLite database at /path/to/mydb.sqlite

You: Connect to MongoDB at localhost, database 'myapp'
You: Find all users older than 25

{
  "mcpServers": {
    "database-explorer": {
      "command": "node",
      "args": ["/path/to/build/index.js"],
      "env": {
        "DB_EXPLORER_READONLY": "true",
        "DB_EXPLORER_MAX_ROWS": "200"
      }
    }
  }
}

src/
├── index.ts              # Entry point (stdio transport + env config)
├── server.ts             # MCP server setup, tool/prompt/resource registration
├── types.ts              # Shared TypeScript interfaces + SQL safety patterns
├── connection-manager.ts # Connection lifecycle management
├── connectors/
│   ├── base.ts           # Abstract connector interface
│   ├── postgresql.ts     # PostgreSQL (pg driver)
│   ├── mysql.ts          # MySQL (mysql2 driver)
│   ├── sqlite.ts         # SQLite (better-sqlite3)
│   └── mongodb.ts        # MongoDB (mongodb driver)
└── tools/
    ├── connect.ts        # connect/disconnect/list
    ├── schema.ts         # list_tables/describe_table/get_schema
    ├── query.ts          # run_query/explain_query + SQL safety
    ├── stats.ts          # get_table_stats
    ├── optimize.ts       # suggest_indexes
    ├── export.ts         # export_data
    ├── erd.ts            # generate_erd (Mermaid)
    └── search.ts         # search_data

npm test

✔ connects to SQLite database
✔ lists all tables
✔ describes table with columns and types
✔ describes table with foreign keys
✔ gets indexes for a table
✔ gets full database schema
✔ runs SELECT query
✔ runs JOIN query
✔ runs aggregate query
✔ runs INSERT query (write mode)
✔ explains query plan
✔ gets table stats for all tables
✔ gets table stats for specific table
✔ blocks DROP statements
✔ blocks TRUNCATE statements
✔ blocks ALTER statements
✔ blocks INSERT statements
✔ allows SELECT statements
✔ allows EXPLAIN statements
✔ connects via connection manager
✔ lists connections
✔ throws on missing connection
✔ stores server config

23 pass / 0 fail