Database-Per-Service Pattern
Enforce true domain encapsulation: Private databases, independent schema migrations, polyglot storage, and preventing backdoor table coupling.
01.1. The Golden Rule of Microservices Architecture
The absolute foundation of microservices architecture is the Database-per-Service pattern:
The Golden Rule: Every microservice must have exclusive, private ownership over its persistent data store. No other service in the entire organization is permitted to read or write directly to another service's database tables.
All data retrieval and state modification must pass through the owning service's public, versioned API contract (e.g., gRPC, REST) or subscribed asynchronous domain event streams.
If Service A opens a database connection directly to Service B's PostgreSQL instance to execute a SELECT or UPDATE, you do not have microservices—you have a fragile Distributed Monolith with SQL Backdoors.
Database-Per-Service Encapsulation & Polyglot Persistence 🗄️
Database-Per-Service Encapsulation & Polyglot Persistence 🗄️
Services have exclusive ownership of their persistent data stores. Cross-service data access occurs exclusively over verified public APIs or asynchronous event streams.
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