This topic describes the relationship between parent and child data sources.
Discovery Framework data sources can have parents and children. These relationships can be set in a data source's JSON file through the parentDataSource:parent-ds-id property.
In behavior, child data sources act like immutable filter sets. If you are using a child data source, the baseFunctions setting in the data source file should be specified with some set of filters. When a component connected to a child data source attempts to get the current query state, the query state is the query state of the data source's parent with all of the static filters on the child (as specified in configuration as baseFunctions) appended to it.
When a component connected to a child data source attempts to change that data source's query state (by setting a refinement from Guided Navigation, for example), the change actually happens on the parent data source. Such an operation keeps applying to a data source's parent until it finds a data source without a parent. When any data source's query state is changed, the query states of all of its children are effectively changed as well, and any components connected to them will refresh.
Parent/child data sources are not supported on MDEX 7. You should not include the parentId attribute in your MDEX 7 data source JSON configuration files.