Introducing Field Dependencies

Now that we've made all those picklists, answer this question: How many times have you clicked on a drop-down list and found far too many values to choose from? For example, maybe you were selecting Uruguay from a list of countries, and every country in the world was on the list. That meant that you had to scroll all the way down to the countries that started with the letter U. What a pain!

Fortunately, the folks who built the Force.com platform have encountered that situation a few times themselves, and as a result, they've given us a tool to help us avoid this problem with our own picklist fields: field dependencies.

Field dependencies are filters that allow us to change the contents of a picklist based on the value of another field. For example, rather than displaying every value for Country in a single picklist, we can limit the values that are displayed based on a value for another field, like Continent. That way our users can find the appropriate country more quickly and easily.

Picklist fields can be either controlling or dependent fields. A controlling field controls the available values in one or more corresponding dependent fields. A dependent field displays values based on the value selected in its corresponding controlling field. In the previous example, the Continent picklist is the controlling field, while the Country picklist is the dependent field.