Data Nexus MCP

A modular, secure platform for connecting to SQL and NoSQL databases via REST API, MCP (Model Context Protocol), and a Vue.js Web UI.

Architecture

┌─────────────┐     ┌──────────────┐     ┌─────────────────┐
│   Web UI    │────▶│  REST API    │────▶│ core-db-command │
│  (Vue.js)   │     │  (FastAPI)   │     │  (Python lib)   │
└─────────────┘     └──────┬───────┘     └────────┬────────┘
                           │                       │
                    ┌──────▼───────┐               │
                    │  MCP Server  │───────────────┘
                    └──────┬───────┘
                           │
                    ┌──────▼───────┐
                    │  MCP Client  │──▶ AI Agents / LLMs
                    └──────────────┘

Modules

Module	Package	Description
core-db-command	core_db_command/	Plugin-based Python library for all database drivers
rest-api-command	rest_api_command/	FastAPI REST layer with OAuth2/LDAP/basic auth
mcp-server	mcp_server/	MCP tools: query_database, get_schema, list_tables, describe_table, execute_sql
mcp-client	mcp_client/	MCP client bridge for agent integration
web-ui	web-ui/	Vue 3 + Pinia + Monaco Editor query studio
config	config/	YAML connection definitions with ${ENV} substitution

Supported Database Types

The driver registry supports 50+ database types across 13 categories:

• Relational: PostgreSQL, MySQL, MSSQL, Oracle, CockroachDB, TiDB, YugabyteDB, TimescaleDB, pgvector
• Document: MongoDB, DocumentDB, Firestore, Couchbase (stub)
• Key-Value: Redis, DynamoDB, Memcached/etcd/RocksDB (stub)
• Wide-Column: Cassandra, ScyllaDB, Bigtable/HBase (stub)
• Graph: Neo4j, Neptune/JanusGraph/ArangoDB (stub)
• Time-Series: InfluxDB, ClickHouse, Prometheus/QuestDB (stub)
• Vector: Qdrant, Weaviate, Milvus, Pinecone
• Search: Elasticsearch, OpenSearch, Splunk/Solr (stub)
• Warehouse: BigQuery, Snowflake, Redshift/Databricks (stub)
• Multi-Model: Cosmos DB, OrientDB (stub)
• Embedded: SQLite, DuckDB, Realm/LMDB (stub)
• Ledger: QLDB/BigchainDB (stub)
• NewSQL: Spanner (stub)

Fully implemented drivers include PostgreSQL, MySQL, MSSQL, Oracle, MongoDB, Redis, SQLite, DuckDB, Elasticsearch, ClickHouse, Neo4j, InfluxDB, Cassandra, DynamoDB, BigQuery, Snowflake, Qdrant, Weaviate, Milvus, Pinecone, Cosmos DB, and Firestore. Stub drivers are registered and extensible.

Quick Start

Prerequisites

• Python 3.11+
• Node.js 20+ (for Web UI development)
• Docker & Docker Compose (optional)

1. Install Python dependencies

cp .env.example .env
pip install -e ".[dev]"

2. Configure connections

Edit config/connections.yaml and set secrets via environment variables:

connections:
  - name: postgres_prod
    type: postgresql
    host: localhost
    port: 5432
    database: mydb
    user: readonly_user
    password: ${PG_PASSWORD}

3. Start the REST API

db-rest-api
# or: uvicorn rest_api_command.app:app --reload

API docs: http://localhost:8000/docs

4. Start the Web UI (development)

cd web-ui
cp .env.example .env
npm install
npm run dev

Open http://localhost:5173 — default credentials: admin / changeme

5. Run with Docker Compose

docker compose up -d

Services:

• REST API: http://localhost:8000
• Web UI: http://localhost:5173
• PostgreSQL, MySQL, MongoDB, Redis, Elasticsearch

REST API Endpoints

Method	Path	Description
GET	/api/connections	List connections (no credentials)
POST	/api/db/{name}/query	Parameterized query
POST	/api/db/{name}/sql	Raw SQL / native command
GET	/api/db/{name}/schema	Database schema
GET	/api/db/{name}/tables	List tables/collections
GET	/api/db/{name}/tables/{table}/describe	Table structure
GET/POST	/api/query-history	Query history

MCP Server

Configure in .env or Cursor MCP env:

MCP_REST_API_URL=http://localhost:8000
# Option A: bearer token (when REST_API_AUTH_MODE=oauth2)
MCP_REST_API_TOKEN=<jwt-from-/api/auth/token>
# Option B: username/password (works with basic auth; auto-fetches JWT if oauth2)
MCP_REST_API_USER=admin
MCP_REST_API_PASSWORD=changeme

Run:

db-mcp-server

Add to Cursor/Claude MCP config:

{
  "mcpServers": {
    "data-nexus-mcp": {
      "command": "db-mcp-server",
      "cwd": "/path/to/data_nexus_mcp",
      "env": {
        "MCP_REST_API_URL": "http://localhost:8000",
        "MCP_REST_API_USER": "admin",
        "MCP_REST_API_PASSWORD": "changeme"
      }
    }
  }
}

Note: REST_API_* variables belong on the REST API process (db-rest-api), not in the MCP server config.

MCP Client

db-mcp-client                    # list available tools
db-mcp-client query local_sqlite "SELECT 1"

Authentication

Set REST_API_AUTH_MODE to one of:

• basic — HTTP Basic Auth (default for development)
• oauth2 — JWT bearer tokens via /api/auth/token
• ldap — LDAP bind (requires REST_API_LDAP_SERVER and REST_API_LDAP_BASE_DN)

Adding a New Driver

1. Create core_db_command/drivers/mydb.py
2. Subclass BaseDriver and set driver_type
3. Decorate with @DriverRegistry.register
4. Import in core_db_command/drivers/registry_loader.py

from core_db_command.base import BaseDriver, DriverRegistry

@DriverRegistry.register
class MyDBDriver(BaseDriver):
    driver_type = "mydb"

    async def connect(self): ...
    async def disconnect(self): ...
    async def query(self, query, params=None): ...
    async def execute(self, command, params=None): ...
    async def list_tables(self, schema=None): ...
    async def describe_table(self, table, schema=None): ...

Testing

pytest tests/ -v

Security Notes

• Credentials are never returned by the REST API or MCP server
• Secrets must use ${ENV_VAR} placeholders in YAML config
• All API endpoints require authentication
• Query input is validated and length-limited

Project Structure

data-nexus-mcp/
├── core_db_command/       # Core library + drivers
├── rest_api_command/      # FastAPI REST API
├── mcp_server/            # MCP server
├── mcp_client/            # MCP client
├── web-ui/                # Vue.js frontend
├── config/                # YAML connection config
├── tests/                 # Unit tests
├── docker-compose.yml
├── Dockerfile
└── pyproject.toml

License

MIT