Here in this blog, we will be discussing how we can query the lagom’s microservices for retrieving data. I hope you are clear with persistent entity concepts in lagom, if not, you can take a quick overview by going through this blog.
Lagom handles data persistence by using ‘Persistent Entity’ which holds the state of individual entities, but to interact with them one must know the identifier of the entity. Hence, Lagom provides support to build read-side view of the persistent data which can be used for querying purpose.
And, this separation of the write-side and the read-side of the persistent data is often referred to as the CQRS (Command Query Responsibility Segregation) pattern.
Read side can be implemented using any database. For now, we will be using Cassandra to understand its concepts.
One thing to keep in mind is that read side should only be updated…
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