This document provides an overview and comparison of RDBMS, Hadoop, and Spark. It introduces RDBMS and describes its use cases such as online transaction processing and data warehouses. It then introduces Hadoop and describes its ecosystem including HDFS, YARN, MapReduce, and related sub-modules. Common use cases for Hadoop are also outlined. Spark is then introduced along with its modules like Spark Core, SQL, and MLlib. Use cases for Spark include data enrichment, trigger event detection, and machine learning. The document concludes by comparing RDBMS and Hadoop, as well as Hadoop and Spark, and addressing common misconceptions about Hadoop and Spark.