Managing Schema Evolution in NoSQL Data Stores

NoSQL data stores are commonly schema-less, providing no means for globally defining or managing the schema. While this offers great flexibility in early stages of application development, devel-opers soon can experience the heavy burden of dealing with in-creasingly heterogeneous data. This paper targets schema evolution for NoSQL data stores, the complex task of adapting and chang-ing the implicit structure of the data stored. We discuss the re-commendations of the developer community on handling schema changes, and introduce a simple, declarative schema evolution lan-guage. With our language, software developers and architects can systematically manage the evolution of their production data and perform typical schema maintenance tasks. We further provide a holistic NoSQL database programming language to define the se-mantics of our schema evolution language. Our solution does not require any modifications to the NoSQL data store, treating the data store as a black box. Thus, we want to address application develop-ers that use NoSQL systems as database-as-a-service.