You have applied the Microservices architecture pattern and the Database per service pattern. As a result, it is no longer straightforward to implement queries that join data from multiple services. Also, if you have applied the Event sourcing pattern then the data is no longer easily queried.
How to implement a query that retrieves data from multiple services in a microservice architecture?
Define a view database, which is a read-only replica that is designed to support that query. The application keeps the replica up to data by subscribing to Domain events published by the service that own the data.
My book’s FTGO example application has the
Order History Service, which implements this pattern.
There are several Eventuate-based example applications that illustrate how to use this pattern.
This pattern has the following benefits:
This pattern has the following drawbacks:
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