the database-per-service pattern

The Database-per-Service Pattern

The database-per-service pattern, also known as the private table pattern, is a design pattern that involves having a separate database instance for each microservice in your application. This means that each service has its own private database, which it can use to store and retrieve data without interfering with other services.

One of the main advantages of this pattern is that it allows for greater scalability and flexibility. By isolating each service in its own database, you can easily scale up or down individual services as needed, without affecting the rest of the application. This can be particularly useful if you have some services that receive a lot of traffic and others that are less frequently used.

Another advantage of the database-per-service pattern is that it can help to reduce the risk of data corruption or loss. Because each service has its own private database, there is less chance of data being accidentally overwritten or deleted by another service. This can be particularly important if you are working with sensitive or mission-critical data.

Implementing the Pattern

To implement the database-per-service pattern, you will need to create a separate database instance for each microservice in your application. This can be done using any number of database technologies, including SQL or NoSQL databases.

// Example of creating a separate MongoDB database for a service
const MongoClient = require('mongodb').MongoClient;
const uri = "mongodb+srv://username:[email protected]/myFirstDatabase?retryWrites=true&w=majority";
const client = new MongoClient(uri, { useNewUrlParser: true, useUnifiedTopology: true });
client.connect(err => {
  const collection = client.db("myDatabase").collection("myCollection");
  // perform operations on the collection object
  client.close();
});

Once you have created the separate database instances, you will need to ensure that each service only accesses its own database. This can be done by configuring the service's database connection settings to point to the correct database instance.

Alternative Approaches

While the database-per-service pattern is a popular approach for microservice architecture, there are several alternative approaches that can be used depending on the specific needs of your application.

One alternative approach is to use a shared database instance for multiple services. This can be useful if you have a smaller number of services that are tightly coupled and need to share data. However, this approach can also increase the risk of data corruption or loss, as multiple services will be accessing the same database.

Another alternative approach is to use an event-driven architecture, where services communicate with each other through events rather than direct database access. This can help to reduce coupling between services and allow for greater flexibility and scalability.