Amazon QuickSight
User Guide

Working with Data Sets

A data set identifies the specific data in a data source that you want to use, for example a table if you are connecting to a database data source, or a file if you are connecting to an Amazon S3 data source. A data set also stores any data preparation you have performed on that data (like renaming a field or changing its data type), so you don't have to re-prepare the data each time you want to create an analysis based on it.