Optional Data in RAD

In some situations, data might be declared as nullable. Nullable data can take on a "non-value", for example, NULL in C, None in Python, or null in Java. Conversely, non-nullable data cannot be NULL. Only data of type opaque, string, secret, array, or structure can be declared nullable. Additionally, only structure fields and certain API types can be nullable. Specifically, array data cannot be nullable because the array type in RAD is actually more like a list than an array.