A company is building a mobile app to provide shopping recommendations to its customers.

Amazon Neptune is a service that provides a fully managed graph database that supports property graphs and RDF graphs. It can be used to build applications that work with highly connected datasets, such as shopping recommendations, social networks, fraud detection, and knowledge graphs2. Amazon DynamoDB is a service that provides a fully managed NoSQL database that delivers fast and consistent performance at any scale. Amazon Aurora is a service that provides a fully managed relational database that is compatible with MySQL and PostgreSQL. Amazon DocumentDB (with MongoDB compatibility) is a service that provides a fully managed document database that is compatible with MongoDB.