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MCP Database Integrations: PostgreSQL, MySQL, MongoDB and Beyond

· 9 min read
ToolBoost Team
ToolBoost Team
ToolBoost Engineering Team

Connecting AI to your databases unlocks powerful data analysis, debugging, and automation capabilities. This guide covers everything you need to know about database MCPs.

Why Connect AI to Databases?​

Traditional Database Work:

1. Open database client (pgAdmin, MySQL Workbench, etc.)
2. Write SQL query
3. Execute
4. Copy results
5. Paste into AI for analysis
6. Get insights
7. Write new query based on insights
8. Repeat...

With Database MCP:

"Show me users who haven't logged in for 30 days"
→ AI writes query, executes it, analyzes results
→ Done in seconds

PostgreSQL MCP​

The most popular relational database MCP.

Setup with ToolBoost​

  1. Go to ToolBoost Catalog
  2. Search for "PostgreSQL MCP"
  3. Click "Deploy Server"
  4. Configure environment variables:
DATABASE_URL=postgresql://username:password@host:5432/database
# Or individual params:
PGHOST=your-db-host.com
PGPORT=5432
PGDATABASE=your_database
PGUSER=your_username
PGPASSWORD=your_password
  1. Copy connection URL
  2. Add to your AI client

What You Can Do​

Schema Exploration:

"List all tables in the database"
"Describe the users table schema"
"Show me all indexes on the orders table"

Data Analysis:

"How many users signed up this month?"
"What's the average order value by customer segment?"
"Show me the top 10 products by revenue"

Debugging:

"Find slow queries from the past hour"
"Check for missing indexes on frequently queried columns"
"Identify tables without primary keys"

Data Quality:

"Find duplicate email addresses in users table"
"Check for NULL values in required fields"
"Show me orphaned records in orders table (no matching user)"

Security Best Practices​

1. Use Read-Only User (Recommended)

-- Create read-only user for MCP
CREATE USER mcp_readonly WITH PASSWORD 'secure_password';

-- Grant SELECT on all tables
GRANT CONNECT ON DATABASE your_database TO mcp_readonly;
GRANT USAGE ON SCHEMA public TO mcp_readonly;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO mcp_readonly;

-- Grant SELECT on future tables
ALTER DEFAULT PRIVILEGES IN SCHEMA public
  GRANT SELECT ON TABLES TO mcp_readonly;

2. Use Connection Pooling

# For high-traffic scenarios
DATABASE_URL=postgresql://user:pass@host:5432/db?max=20&min=5

3. Limit Access to Sensitive Tables

-- Revoke access to sensitive tables
REVOKE SELECT ON sensitive_table FROM mcp_readonly;

Advanced Usage​

Custom Queries:

"Run this query and explain the results:
SELECT
  DATE_TRUNC('day', created_at) as day,
  COUNT(*) as signups
FROM users
WHERE created_at > NOW() - INTERVAL '30 days'
GROUP BY day
ORDER BY day"

Query Optimization:

"Analyze this query and suggest optimizations:
SELECT * FROM orders WHERE user_email LIKE '%example.com'"

Migration Generation:

"Generate a migration to add email_verified boolean column to users table"

MySQL MCP​

Similar to PostgreSQL but for MySQL/MariaDB.

Setup​

# Environment variables
MYSQL_HOST=your-mysql-host.com
MYSQL_PORT=3306
MYSQL_DATABASE=your_database
MYSQL_USER=your_username
MYSQL_PASSWORD=your_password

# Or connection string
MYSQL_URL=mysql://username:password@host:3306/database

MySQL-Specific Features​

Storage Engine Analysis:

"Show me which tables are using MyISAM vs InnoDB"
"Suggest storage engine optimizations"

Replication Monitoring:

"Check replication lag"
"Show replica status"

Common Use Cases​

E-commerce Analytics:

"What's our revenue by product category this quarter?"
"Show me cart abandonment rate by hour of day"
"Find our most valuable customers (top 10 by lifetime value)"

Performance Monitoring:

"Show me the slowest queries from the past 24 hours"
"Which tables have the most table scans?"
"Suggest indexes to improve performance"

MongoDB MCP​

NoSQL document database integration.

Setup​

MONGODB_URI=mongodb+srv://username:password@cluster.mongodb.net/database
# Or local
MONGODB_URI=mongodb://localhost:27017/database

Working with Documents​

Query Documents:

"Find all users with email ending in @gmail.com"
"Show me products with price greater than $100"
"Get the most recent 10 orders"

Aggregations:

"Calculate average order value by month"
"Group users by country and count"
"Find top 5 products by number of reviews"

Schema Analysis:

"Analyze the structure of the users collection"
"Find inconsistent document schemas"
"Suggest schema improvements"

MongoDB-Specific Patterns​

Index Management:

"Show me all indexes in the products collection"
"Suggest indexes based on my queries"
"Find unused indexes"

Data Modeling:

"Should I embed or reference user addresses?"
"Analyze my document size distribution"
"Suggest denormalization opportunities"

Supabase MCP​

PostgreSQL with built-in auth, storage, and real-time features.

Setup​

SUPABASE_URL=https://your-project.supabase.co
SUPABASE_ANON_KEY=your-anon-key
# Or service role key for admin access
SUPABASE_SERVICE_ROLE_KEY=your-service-role-key

Unique Capabilities​

Authentication Analysis:

"How many users signed up this week?"
"Show me users who haven't verified their email"
"List all OAuth providers used"

Storage Operations:

"List all files in the avatars bucket"
"Show me the largest files in storage"
"Check storage usage by bucket"

Real-time Subscriptions:

"Show me all active real-time subscriptions"
"Which tables have real-time enabled?"

Row Level Security (RLS):

"Show me RLS policies on the posts table"
"Check which tables don't have RLS enabled"
"Suggest RLS policies for user data"

SQLite MCP​

Lightweight, file-based database.

Setup​

SQLITE_DB_PATH=/path/to/database.db

Use Cases​

Local Development:

"Create a test database with sample data"
"Export data to CSV"
"Analyze my local app database"

Embedded Apps:

"Query my Electron app's local database"
"Check data integrity"
"Compact database file"

Redis MCP​

In-memory data store for caching and pub/sub.

Setup​

REDIS_URL=redis://username:password@host:6379
# Or with SSL
REDIS_URL=rediss://username:password@host:6380

Operations​

Cache Analysis:

"Show me all keys matching 'user:*'"
"What's the cache hit rate?"
"Find keys about to expire"

Data Management:

"Clear all keys matching 'temp:*'"
"Show me the largest keys in memory"
"Check memory usage"

Pub/Sub Monitoring:

"List all active subscriptions"
"Show pub/sub channel stats"

Multi-Database Workflows​

Use multiple database MCPs together for complex workflows.

Example: Cross-Database Analysis​

Scenario: PostgreSQL (primary), Redis (cache), MongoDB (logs)

"Compare user counts between PostgreSQL and MongoDB logs.
 Then check if user sessions are properly cached in Redis."

AI uses:

  1. PostgreSQL MCP → Count users in main database
  2. MongoDB MCP → Count user events in logs
  3. Redis MCP → Check cached sessions
  4. Analyzes discrepancies

Example: Data Migration​

"Read all products from MySQL and suggest how to model them in MongoDB"

AI:

  1. Uses MySQL MCP to read product schema
  2. Analyzes relationships
  3. Suggests MongoDB document structure
  4. Can generate migration script

Advanced Patterns​

1. Automated Monitoring​

Create daily reports:

"Generate a database health report:
- Table sizes
- Index usage
- Slow queries
- Connection pool status
- Replication lag (if applicable)
Save it to our monitoring channel"

2. Data Quality Checks​

Continuous validation:

"Check data quality in the users table:
- Find duplicate emails
- Check for invalid phone numbers
- Identify accounts without profiles
- Flag suspicious activity patterns"

3. Performance Optimization​

Regular maintenance:

"Analyze query performance and suggest:
- Missing indexes
- Inefficient queries
- Tables needing VACUUM (PostgreSQL)
- Buffer pool optimization (MySQL)"

4. Automated Backups​

Backup workflows:

"Create a backup of the users and orders tables.
Export to CSV and save to cloud storage.
Verify backup integrity."

Security Considerations​

1. Network Access​

Firewall Rules:

# Allow ToolBoost IP ranges only
# (provided in ToolBoost documentation)
iptables -A INPUT -p tcp --dport 5432 -s TOOLBOOST_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 5432 -j DROP

VPN/Private Network:

Use ToolBoost Enterprise for VPN connections

2. Credential Management​

❌ Never:

# Don't hardcode in client config
DATABASE_URL=postgresql://admin:password123@public-host.com:5432/prod

✅ Always:

# Use ToolBoost encrypted environment variables
# Configure once in ToolBoost UI, use everywhere

3. Audit Logging​

Track all database queries:

-- PostgreSQL: Enable query logging
ALTER DATABASE your_db SET log_statement = 'all';

-- Review logs regularly
SELECT * FROM pg_stat_activity WHERE query LIKE '%users%';

4. Read-Only by Default​

Start restrictive, grant permissions as needed:

-- Start with read-only
GRANT SELECT ON ALL TABLES TO mcp_user;

-- Add write permissions only where needed
GRANT INSERT, UPDATE ON specific_table TO mcp_user;

-- Never grant
-- GRANT DROP, TRUNCATE, DELETE

Troubleshooting​

Connection Issues​

Problem: "Connection refused"

Solutions:

  • Check firewall allows ToolBoost IPs
  • Verify database is running
  • Confirm host/port are correct
  • Test connection with psql/mysql client first

Timeout Errors​

Problem: Queries timing out

Solutions:

  • Optimize slow queries
  • Add indexes
  • Increase timeout settings
  • Use pagination for large results

Permission Denied​

Problem: "permission denied for table users"

Solutions:

  • Grant SELECT permission
  • Check user has CONNECT on database
  • Verify USAGE on schema
  • Review RLS policies (Supabase)

Best Practices​

1. Use Separate Environments​

Development Project:
  DATABASE_URL=postgresql://dev-db/dev

Staging Project:
  DATABASE_URL=postgresql://staging-db/staging

Production Project:
  DATABASE_URL=postgresql://prod-db/prod (read-only!)

2. Implement Query Limits​

Prevent expensive queries:

-- PostgreSQL: Set statement timeout
ALTER DATABASE your_db SET statement_timeout = '30s';

-- Limit result rows
SET statement_timeout = '10s';
SET max_rows = 1000;

3. Monitor Usage​

Track database MCP usage:

  • Query frequency
  • Response times
  • Error rates
  • Data transferred

ToolBoost provides analytics dashboard.

4. Regular Maintenance​

Schedule periodic tasks:

  • Index maintenance
  • Query optimization review
  • Permission audits
  • Credential rotation

Real-World Success Stories​

E-commerce Company​

Before MCP:

  • Data analysts spent 60% of time writing SQL
  • Business questions took hours to answer
  • Insights often outdated by delivery

After MCP:

  • Business team asks questions directly
  • Real-time answers in seconds
  • Data analysts focus on complex modeling

ROI: 10 hours/week saved per analyst

SaaS Startup​

Challenge: Debugging customer issues required database access

Solution: Support team uses database MCP

Support: "Show me all failed payments for user john@example.com this month"
AI: [Queries database, returns results]
Support: "Update their subscription status to active"
AI: [Safely updates with confirmation]

Result: 50% faster issue resolution

Conclusion​

Database MCPs transform how teams interact with data. From quick queries to complex analysis, AI makes database work faster and more accessible.

Key Takeaways:

  • ✅ Use read-only users for safety
  • ✅ Start with non-production databases
  • ✅ Monitor query performance
  • ✅ Implement proper security
  • ✅ Leverage multi-database workflows

Get Started:

  1. Choose your database MCP
  2. Deploy on ToolBoost
  3. Configure securely
  4. Start asking questions!

Deploy database MCPs instantly with ToolBoost - PostgreSQL, MySQL, MongoDB, and more.

Need help with database integrations? Email databases@toolboost.dev