Good relationships are important in Business, Sports, Personal Life...in anything, really. Good relationships are important with GIS data as well. Let's take a look at how relationship classes and related data can aid in the GIS data collection process.
A client from a Water Reclamation Department uses the Collector for ArcGIS app to edit Sanitary Sewer Network data. They requested additional attributes for a Lift Stations layer, as well as the ability to add multiple Pumps to each Lift Station. The solution to this request is a related table in a feature service that allows for editing via the Collector app. This is an overview of the process.
Create a table and a relationship class in your geodatabase
I created a table for Pumps with the requested attribute information and a Lift Station ID field. The next step was to create a relationship class involving the Lift Stations (Network Structures feature class) and the Pumps table, with the Lift Station ID as the link between the two. In this case, the cardinality for the relationship class is One-To-Many, since there can be multiple Pumps for each Lift Station.
Publish and Configure
Publish the feature service for your data to ArcGIS Online, and include the related table along with the feature class(es). Configure your web map as desired. This map is accessed through the Collector app.
Add and View Related Records
Sign in to Collector and open your map. Tap on a feature to bring up the Details panel. In this example, I tapped on Lift Station, and scrolled to the bottom of the Details panel.
Under Lift Station Pumps, there are options to View existing related records; or add New related records.
Click New, and attribute information for Pumps displays in the panel.
Edit the attribute information as necessary. Note the ID field is populated with the identifier of the original Lift Station feature.
Click Submit, and your edits are saved to the Feature Service. Repeat as necessary to add additional related records.