Using Presto to query on data both on Hive and MongoDB, although added each related connector.

There are some queries for do aggregations on data collected from crawling two websites and filtering needed data.

This part have some strategies for adding data to Redis, due to the required question. Also, a temporal and spatial cache is implemented too.

Designing proper databases to answer the asked question in a way that is possible for Cassandra to answer with respect to its limitations.

Queries on a graph-based database by traversing its edges.