The CQRS pattern can be useful for applications that need to work with the same data in multiple models, potentially stored in different kinds of databases. From an operational perspective, the pattern supports domain-driven design’s core value of working with the most effective models for the task at hand, and continuously improving the model of the business domain. From an infrastructural perspective, CQRS allows for leveraging the strength of the different kinds of databases; for exam‐ ple, using a relational database to store the command execution model, a search index for full text search, and prerendered flat files for fast data retrieval, with all the storage mechanisms reliably synchronized.

Moreover, CQRS naturally lends itself to event-sourced domain models. The event- sourcing model makes it impossible to query records based on the aggregates’ states, but CQRS enables this by projecting the states into queryable databases.