A feature set is a lightweight data format that contains the feature schema (such as fields, the spatial reference, and the geometry type) and the actual data itself, much like a feature class. The feature set is a format that makes it easy and efficient to interact with GIS web services published on a server, including ArcGIS Online, Portal for ArcGIS, and ArcGIS for Server. If you run a tool or geoprocessing service using a server environment, the data format used in these processes is called feature sets and record sets. For the purposes of this chapter, we will be reviewing only feature sets.
It is important to note that when loading data into a feature set from a feature class, any updates on the feature set will affect the original feature class. For example, if you write a script that includes an update cursor or field calculation on the feature set, you will...