Database Integrations
2 min read
Connecting Claude Code to databases via MCP servers
title: Database Integrations description: Connecting Claude Code to databases via MCP servers
Claude Code can interact with databases through MCP (Model Context Protocol) servers. This enables querying, schema exploration, and data analysis directly from your Claude conversations.
Overview
Database integration with Claude Code works through MCP servers that act as secure bridges between Claude and your databases. This approach:
- Keeps credentials secure on the server
- Allows fine-grained access control
- Supports multiple database types
- Enables complex queries and analysis
PostgreSQL Integration
MCP Server Setup
JSON
// .claude/settings.json
{
"mcpServers": {
"postgres": {
"command": "npx",
"args": ["@modelcontextprotocol/server-postgres"],
"env": {
"POSTGRES_URL": "postgresql://user:pass@localhost:5432/mydb"
}
}
}
}
Usage Examples
Explore schema:
Text
Show me the database schema for the users table
Query data:
Text
Find all users who signed up in the last 30 days
and haven't made a purchase
Analyze patterns:
Text
What are the most common user journeys
based on the events table?
MySQL / MariaDB Integration
Server Configuration
JSON
{
"mcpServers": {
"mysql": {
"command": "npx",
"args": ["@modelcontextprotocol/server-mysql"],
"env": {
"MYSQL_HOST": "localhost",
"MYSQL_PORT": "3306",
"MYSQL_USER": "claude",
"MYSQL_PASSWORD": "${MYSQL_PASSWORD}",
"MYSQL_DATABASE": "production"
}
}
}
}
Read-Only Mode
For safety, configure read-only access:
SQL
-- Create a read-only user
CREATE USER 'claude'@'%' IDENTIFIED BY 'secure_password';
GRANT SELECT ON production.* TO 'claude'@'%';
FLUSH PRIVILEGES;
SQLite Integration
Local Database
JSON
{
"mcpServers": {
"sqlite": {
"command": "npx",
"args": ["@modelcontextprotocol/server-sqlite", "path/to/database.db"]
}
}
}
Memory Database for Testing
JSON
{
"mcpServers": {
"sqlite-memory": {
"command": "npx",
"args": ["@modelcontextprotocol/server-sqlite", ":memory:"]
}
}
}
MongoDB Integration
Connection Setup
JSON
{
"mcpServers": {
"mongodb": {
"command": "npx",
"args": ["@modelcontextprotocol/server-mongodb"],
"env": {
"MONGODB_URI": "mongodb://localhost:27017/myapp"
}
}
}
}
Working with Collections
Text
List all collections in the database
Text
Find documents in the orders collection
where status is "pending" and total is over $100
Text
Show me the schema/shape of documents
in the users collection
Redis Integration
Configuration
JSON
{
"mcpServers": {
"redis": {
"command": "npx",
"args": ["@modelcontextprotocol/server-redis"],
"env": {
"REDIS_URL": "redis://localhost:6379"
}
}
}
}
Common Operations
Text
Show all keys matching "session:*"
Text
What's the value stored at key "config:feature_flags"?
Text
Show memory usage and key statistics
Security Best Practices
1. Use Read-Only Accounts
Always create database users with minimal permissions:
SQL
-- PostgreSQL
CREATE ROLE claude_readonly WITH LOGIN PASSWORD 'secure_pass';
GRANT CONNECT ON DATABASE myapp TO claude_readonly;
GRANT USAGE ON SCHEMA public TO claude_readonly;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO claude_readonly;
2. Environment Variables
Never hardcode credentials:
JSON
{
"mcpServers": {
"postgres": {
"command": "npx",
"args": ["@modelcontextprotocol/server-postgres"],
"env": {
"POSTGRES_URL": "${POSTGRES_URL}" // From environment
}
}
}
}
3. Connection Limits
Configure connection pooling:
JSON
{
"env": {
"POSTGRES_URL": "postgresql://user:pass@host/db?pool_size=5&pool_timeout=30"
}
}
4. Query Timeouts
Set reasonable timeouts:
JSON
{
"env": {
"POSTGRES_URL": "postgresql://user:pass@host/db?statement_timeout=30000"
}
}
5. Audit Logging
Enable query logging for audit:
SQL
-- PostgreSQL
ALTER SYSTEM SET log_statement = 'all';
ALTER SYSTEM SET log_min_duration_statement = 0;
SELECT pg_reload_conf();
Common Workflows
Schema Exploration
Text
I'm working on the orders system.
Show me all tables and their relationships.
Which tables reference the users table?
Data Analysis
Text
Analyze the orders table:
- What's the average order value by month?
- Which products are most frequently ordered together?
- What's the customer retention rate?
Query Optimization
Text
This query is slow:
SELECT * FROM orders o
JOIN users u ON o.user_id = u.id
WHERE o.created_at > '2024-01-01'
Analyze the execution plan and suggest optimizations.
Data Migration Planning
Text
I need to add a new status field to the orders table.
- Show current status distribution
- Suggest a migration strategy
- What constraints should I add?
Troubleshooting
Connection Issues
"Connection refused":
- Check database is running
- Verify host/port configuration
- Check firewall rules
"Authentication failed":
- Verify credentials
- Check user permissions
- Ensure database exists
MCP Server Issues
"MCP server not found":
Bash
# Install the server
npm install -g @modelcontextprotocol/server-postgres
"Server timeout":
- Increase timeout in settings
- Check network latency
- Verify database responsiveness
Query Errors
"Permission denied":
- Verify user has SELECT permissions
- Check schema access
- Review role grants
"Query too complex":
- Add query timeouts
- Use LIMIT clauses
- Index frequently queried columns
Advanced Configurations
Multiple Databases
JSON
{
"mcpServers": {
"postgres-prod": {
"command": "npx",
"args": ["@modelcontextprotocol/server-postgres"],
"env": { "POSTGRES_URL": "${POSTGRES_PROD_URL}" }
},
"postgres-staging": {
"command": "npx",
"args": ["@modelcontextprotocol/server-postgres"],
"env": { "POSTGRES_URL": "${POSTGRES_STAGING_URL}" }
}
}
}
Custom MCP Server
For specialized needs, create a custom server:
TypeScript
// custom-db-server.ts
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
const server = new Server({
name: "custom-db",
version: "1.0.0",
});
server.setRequestHandler("tools/list", async () => ({
tools: [
{
name: "query",
description: "Execute a database query",
inputSchema: {
type: "object",
properties: {
sql: { type: "string" },
},
required: ["sql"],
},
},
],
}));
server.setRequestHandler("tools/call", async (request) => {
if (request.params.name === "query") {
// Execute query with your custom logic
const result = await executeQuery(request.params.arguments.sql);
return { content: [{ type: "text", text: JSON.stringify(result) }] };
}
});
const transport = new StdioServerTransport();
await server.connect(transport);
Best Practices Summary
-
Always use read-only accounts for Claude database access
-
Set query timeouts to prevent long-running queries
-
Use environment variables for all credentials
-
Enable audit logging to track database access
-
Test in staging first before connecting production databases
-
Review generated queries before execution on sensitive data
-
Use connection pooling to manage resources
-
Index frequently queried columns for performance