Community articleThe Node Hierarchy
Added by IBM contributorIBM on July 26, 2013
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Every node is part of an overall hierarchy that describes the complete form. This hierarchy follows a standard tree structure, with the top of the tree being the top (or root) of the hierarchy.
The diagram in Figure 1 shows the tree structure for a simple form.
The elements of the hierarchy, in descending order, are:
  • Form — Each form has one form level node. This is the root node of the tree.
  • Page — Each form contains pages, which are represented as children of the form node. Each form has at least two page nodes - one for the globalpage, which stores the global settings, and one for the first page of the form.
  • Item — Each page contains items, which are represented as children of the page node. An item node is created for each item, including the global item which stores page settings.
  • Option — Each item contains options, which are represented as children of the item node. An option node is created for each option.
  • Argument — Options often contain further settings, or arguments, which are represented as children of the option node or as children of other argument nodes. There may be more than one level of argument node created below an option node, depending on the settings of the option. The easiest way to access a particular node in the hierarchy is to use a reference. References allow you to locate a specific node without first having to locate the parent of that node.
A sample node hierarchy diagram is shown:
Figure 1. Sample Node Hierarchy
The diagram shows a sample node hierarchy in descending order, breaking down the nodes into their properties.