MCP数据库服务

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MCP Database Service

An MCP server for MySQL, PostgreSQL, Oracle, and Redis with explicit persistent connections and SQL session continuity.

Quick Start

Use Node.js 24 or later and install the service:

npm install -g @jadchene/mcp-database-service

Save the configuration below as databases.json and replace the connection details. Use the absolute path to that file when adding the service.

Codex:

codex mcp add database -- mcp-database-service --config /absolute/path/databases.json

Claude Code:

claude mcp add database -- mcp-database-service --config /absolute/path/databases.json

On Windows, a path such as C:/mcp/database/databases.json works. The client starts the stdio service; no separate background process or HTTP port is needed. The config path can also be supplied through MCP_DATABASE_CONFIG; there is no default config path.

Configuration

{
  "sessionIdleTimeoutMs": 1800000,
  "maxSessions": 32,
  "query": {
    "timeoutMs": 5000
  },
  "logging": {
    "enabled": false,
    "directory": "./logs"
  },
  "databases": [
    {
      "key": "main-mysql",
      "type": "mysql",
      "enable": true,
      "readonly": true,
      "dangerMode": false,
      "codexAutoReview": false,
      "connection": {
        "host": "127.0.0.1",
        "port": 3306,
        "databaseName": "app_db",
        "user": "app_reader",
        "password": "replace-with-password",
        "connectTimeoutMs": 5000,
        "ssl": false
      }
    },
    {
      "key": "main-postgresql",
      "type": "postgresql",
      "enable": false,
      "readonly": true,
      "dangerMode": false,
      "codexAutoReview": false,
      "connection": {
        "host": "127.0.0.1",
        "port": 5432,
        "databaseName": "app_db",
        "user": "app_reader",
        "password": "replace-with-password",
        "connectTimeoutMs": 5000,
        "ssl": false
      }
    },
    {
      "key": "oracle-thick-example",
      "type": "oracle",
      "enable": false,
      "readonly": true,
      "dangerMode": false,
      "codexAutoReview": false,
      "connection": {
        "host": "127.0.0.1",
        "port": 1521,
        "serviceName": "XEPDB1",
        "user": "app_reader",
        "password": "replace-with-password",
        "connectTimeoutMs": 5000,
        "clientMode": "thick",
        "clientLibDir": "C:/oracle/instantclient_19_25"
      }
    },
    {
      "key": "cache-redis",
      "type": "redis",
      "enable": false,
      "readonly": true,
      "dangerMode": false,
      "codexAutoReview": false,
      "connection": {
        "host": "127.0.0.1",
        "port": 6379,
        "databaseName": 0,
        "username": "default",
        "password": "replace-with-password",
        "connectTimeoutMs": 5000
      }
    }
  ]
}

The same configuration is available in databases.example.json. Keep the targets you need, replace their connection details, and set enable to true. Oracle Thin mode uses "clientMode": "thin" without clientLibDir; Redis without authentication can omit username and password. Config values are literal; ${VAR} placeholders are not expanded.

enable: false hides a target and closes its sessions. Configuration reloads automatically or through reload_config; invalid updates keep the last valid config. Connection or permission changes invalidate existing sessions.

Timeouts are in milliseconds. Idle time restarts after each operation, and maxSessions includes connections being established. Logging is off by default; relative log directories resolve from the config directory.

Supported Databases

Redis supports GET, HGETALL, SCAN, and connectivity checks.

Tools

Sessions and Transactions

Call connect with a databaseKey, reuse the returned sessionId for subsequent operations, and call disconnect when finished. Variables, temporary tables, the current schema, and transactions persist within that session.

Run same-session operations sequentially. Reconnect after idle expiry, connection loss, or a service restart. If a write times out or loses its connection, check the result before retrying.

Start SQL transactions with native SQL through execute_statement; use commit_transaction, rollback_transaction, and get_transaction_status to manage them. Queries do not automatically commit or roll back transactions. execute_script uses the current transaction by default; use useTransaction: true for a script-owned transaction without an existing transaction or transaction-control statements in the script. DDL follows the database's own commit rules.

Writes and Approval

Set the target's readonly to false to allow writes. Statements, scripts, and non-empty transaction commits require a client that supports interactive approval; rollback does not require approval.

Optional codexAutoReview: true allows compatible Codex clients to review operations automatically. dangerMode: true overrides readonly and skips approval. Both are disabled by default; database account permissions still apply.

Oracle

Enabled Oracle targets in one process must share the client mode and library directory. DML requires manual commit, and explain_query requires an active transaction.

Development

npm install
npm run build
npm test
npm run verify:reload
npm run verify:package

Agent skill: database-mcp.

License

MIT