Should Each Microservice Have Its Own Database or Table?

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Microservices Data: Separate Database or Just Separate Tables?

The golden rule of microservices is "Database per Service." But does this mean every service needs its own physical database server, or can they just have their own tables in a shared database? The answer depends on one thing: Ownership. Let’s break down your options.

Option 1: Separate Physical Databases

In this model, each service has its own completely independent database (e.g., User Service has a User DB, Order Service has an Order DB).

• Full Independence: One service's database issues won't affect others.
• Tech Flexibility: You can use DynamoDB for one service and RDS for another.
• Perfect Scaling: You can scale the database for a high-traffic service without touching the others.
• Best For: Large, complex systems where services need to be completely isolated.

Option 2: Separate Tables (Shared Database)

Here, you have one database server, but each service is strictly limited to its own set of tables. No service ever touches another service's tables.

• Cost Effective: You only pay for and manage one database instance.
• Simpler Management: Easier to backup and monitor for small teams.
• Strict Rule: You MUST prevent services from "sneaking" a look at other tables.
• Best For: Startups or smaller projects moving toward microservices.

What is NEVER Allowed?

Direct Access: The Order Service should never directly query the User table. It must ask the User Service via an API.

Shared Tables: Two services should never write to or read from the exact same table. This creates "Tight Coupling" and leads to deployment nightmares.

Real-Life Example: Food Delivery App

Imagine a food app with three services:
• Customer Service: Owns the Customer table.
• Restaurant Service: Owns the Restaurant table.
• Order Service: Owns the Order table.

If the Order Service needs customer info, it calls the Customer Service API. It never goes behind its back to read the database directly!

💡 PRO TIP: Data Ownership is more important than the physical location of the data. As long as only ONE service controls a specific piece of data, you are following the Microservices way!

Watch the full video above for a complete visual guide on these two database patterns!