Making a simple list of items is easy but is not always sufficient. In many cases, you would need to express a hierarchy by showing selectable lists of the items in each hierarchy level. Selection of any item shows that item's children in the next list. In order to create a cascaded list your data should be tree-shaped. The hierarchy of your data might be deep, and it might have many items on each level.

Let’s take a simple example of airports and countries. You want to build a simple app to keep a log of different flights reservations your company is making. 

So in order to create a working cascaded list, you need to create two lists. First, a table of countries called “Countries”. Second, a table of Airports with a field type “linked list” linked with “Countries”.

This log is composed of the following fields:

  1. Name, text.
  2. Flying from – Countries, list of 227 countries.
  3. Flying from – Airports, list of 7940 airports worldwide.
  4. Date and time of Departure. 
  5. Flying To – Countries, list of 227 countries.
  6. Flying To – Airports, list of 7940 airports worldwide.
  7. Date and time of Arrival.
  8. Status, fixed list (Confirmed, Canceled, Waiting List)

The list of airports is dependent on countries, if you are to chose the Netherlands for instance, a list 16 existing airports of the country should appear only.

Then in your reservation table, create one field type “linked list” linked with “Countries”. Now comes the fun part:

  1. Created a linked list field type and link it with “Airports”. 
  2. Select the option “Cascaded”. Upon clicking on this option an addition dropdown list will appear. 
  3. Choose the field name of the parent value.
  4. Click Save.

Now check how awesome this is by creating a new record as follow:

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