This page describes the format of ICQ query interfaces. Each interface is modeled as an ordered tree. Ordered tree representation captures the grouping of fields and the nested structure of interfaces. Here is an example of query interfaces (for American Airlines) and here is its corresponding ordered tree representation described with a text file which can divided into four sections.

• Section 1: This section gives the total number of nodes in the tree. The section starts with "# number of nodes" and ends with "# end". E.g.

    # number of nodes
    21
    # end
  

  This means that there are 21 nodes (both leaf and internal) in the ordered tree.
• Section 2: Each node in the ordered tree is assigned with a number for the identification purpose. This section gives the id number for the root node. The section starts with "# root" and ends with "# end". E.g. the root id for the above example is 21.

    # root
    21
    # end
  

• Section 3: This section gives the detailed information for each node. This section is from a line starting with "# nodes" to the next line of "# end".

  A node may be a leaf node which corresponds to a field on the interface or an internal node of the ordered tree. Each line starts a description of a node and starts with the node id, followed by other properties of the field, with the description of each property being enclosed in a pair of double quotes and the description of different properties being separated by commas.

  For leaf node, the first property is name, followed by label, and then if present, instances and format, in this order. E.g. this line described node #9 whose name is "numAdultPassengers", the label is "Adults", and has instance "1, 2, 3, 4, 5, 6".

    9, "numAdultPassengers", "Adults", "1, 2, 3, 4, 5, 6"
  

  For internal nodes, only label property needs to be given. E.g. node #15 is an internal node with label "departure date".

    15, "", "Departure Date"
  

• Section 4: This section gives the edges of the tree. The section starts with "# edges" and ends with "# end". Each line starts with the id of an internal node, followed by a '-' and by an ordered list of its child nodes separated by commas.

    # edges 
    21-19,20,17,18,13,14
    19-1,2
    20-15,16
    15-3,4,5
    16-6,7,8
    17-9,10
    18-11,12
    # end
  

  For example, the first line says that the node #21 (which is root) has six children: #19, #20, ..., #14, with #19 being the left-most child.