This page is the entry-point to a series of graphical views of the ONIX DTD Release 1.2. The DTD contains over 230 data elements and composite elements, organised into 23 Groups. These groups are further organised into 9 Supergroups, according to the way in which groups of elements should be used together within an ONIX record. Further information on the inter-dependence of elements within in each group and each supergroup may be found in the ONIX Level 2 Guide.

Each page presents a graphical view of part of the ONIX DTD. This view illustrates the element structure, showing how data elements are combined into groups and, in some cases, into composite elements. It does not in any way try to explain the rules governing the content of each data element.

WARNING! – For convenience, these views show Groups and SuperGroups as if they were composite elements. In reality they are not elements at all, but simply a convenient way of labelling sets of elements whose occurrence within an ONIX message are in some way inter-dependent. Neither Groups nor SuperGroups are ever to be represented explicitly by XML tags.

The following graphical conventions apply:

• Pale blue rectangles represent the elements of an ONIX message. It should be noted, however, that Groups and SuperGroups are not explicit elements and are never be tagged as such. However, they provide a convenient way of arranging elements into dependent groups and are included in these drawings for clarity. Generally, a decision to include an element from a particular Group and SuperGroup will make it necessary to include other mandatory elements and possibly other elements in the same Group and SuperGroup. See the main part of the Guide for further explanation.

• Composite elements are to the left with the composite and data elements they contain to the right. Child elements are joined to their parents by red lines

• Where the contents of a particular structure is a sequence of child elements, the red line divides to create a square bracket with the first and last child elements in the sequence linked respectively to the top and bottom of the square bracket.

• Where the contents of a particular structure is a choice of child elements, the red line divides to create an angle bracket embracing the set of elements from which a choice must be made (the ordering of the elements in this case is insignificant).

• Boxes containing the symbols “?”, “1”, “*” and “+” indicate that the structures to which they are connected to their right are respectively “optional and non-repeatable”, “mandatory and non-repeatable”, “optional and repeatable” and “mandatory and repeatable”. The absence of such a symbol between a structure and its parent indicates that the structure is “mandatory”. NOTE – The term “optional” means that the structure is not mandatory in all circumstances, however it may nevertheless be mandatory in specific circumstances, depending upon the choice and content of other elements.

• Small symbols at the bottom-right of each pale blue box indicate whether the element is a composite (“<->”) or data element.