Cascade or drill-down forms are the types of forms that the values listed in one field depend on the value selected in another field.
In this example, we have multiple databases:
In the steps below, we will capture points representing car layer: the choices from the value relation will be filtered based on the previous field user picks. For example, if user selects Trucks as Car type (truck/car), the Car-Manufacturer field will present user with DAF Trucks, Scania or MAN. Likewise, the next drop-down menu for Car-Model will change accordingly based on the Car-Manufacturer selection.
To set up a the cascade form:
- Download and open this example project in QGIS
- From the layer panel, right-click on car layer and select Properties
- In the new window, select Attributes form
- See Value Relations configuration for the following fields:
- See also Filter expressions applied to the following fields:
In addition to the value relations in the survey layer, we need to set up value relation for the following non-spatial tables and the associated fields: - manufacturer field from car-model table - type field from car-manufacturer table - car-type field from wheel-check table
To use the cascade form in Input:
- Open Input on your device and from Projects > Explore download documentation\form_cascade
- Open the project
- Select Record and add a point
- The form will appear
- Under Survey tab, for Car-type select Car.
- Manufacturer field should short list Mercedes-Benz, Skoda and Audi. Select Audi
- For Car-Model select A8