13.4 Summary

• Spring Data supports reactive persistence for a variety of database types, including relational databases (with R2DBC), MongoDB, and Cassandra.
• Spring Data R2DBC offers a reactive option for relational persistence but doesn’t yet directly support relationships in domain classes.
• For lack of direct relationship support, Spring Data R2DBC repositories require a different approach to domain and database table design.
• Spring Data MongoDB and Spring Data Cassandra offer a near-identical programming model for writing reactive repositories for MongoDB and Cassandra databases.
• Using Spring Data test annotations along with StepVerifier, you can test automatically created reactive repositories from the Spring application context.