Some data in XML documents are one dimensional, for example, <para>Sentence</para>. Some data, however, is structured, as shown in the following XML snippet.
<SubTotal> <Amount>2998</Amount> <CurrencyCode>USD</CurrencyCode> <FormattedPrice>$29.98</FormattedPrice> </SubTotal>
This example shows that the subtotal is comprised of three pieces of data:
FormattedPrice. The example also shows that there can be
a hierarchy of tags. In this example, Amount is a child tag of Subtotal. These
structures represent arrays of values.