Like system lookup tables, custom lookup tables can be hierarchical in nature, automatically start with a Root node, and appear in the order specified for each item in the table.

Each custom lookup table is identified by its four-character alphanumeric unique code, which is assigned when you create the table.

Each item in a custom lookup table is assigned a partial tree position, a four-character alphanumeric combination, when you add it to the table.

To identify the option selected as a value in a custom field of type List when using the API, XML Layer, or other back end functionality, you must use the full tree position of the corresponding item in the custom lookup table associated with the field.

It starts with the unique code of the table + ROOT and includes the partial tree position of the parent items (if there are any) and the selected item itself, in UPPERCASE and separated by underscores, for example, OCCU_ROOT_HURE_HRAS.