XFA Specification
Chapter 19, Data Description Specification
Data Description Element Reference
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Data Description Element Reference
All of the elements and attributes described in this section must belong to the following namespace:
http://ns.adobe.com/data-description/
Note that the trailing “/”
is
required.
dd:dataDescription Element
This element is the container for a data description. More than one
dataDescription
element may
reside in a
dataset
element.
dd:name attribute
This attribute supplies a name for the data description. The attribute must be supplied and the name (“XFA
Names” on page 70)
must be unique across
dataDescription
elements. If the name is the same as the
name of the template's root subform, this data description is the default data description.
dd:group Element
This element groups together its child elements, but without there being a corresponding element in the
data document. For example, the “location” element in a data document contains either an “
x
” element
followed by a "
y
" element, or an “
r
” element followed by a
theta
element. Hence the following is a valid
fragment:
<location>
<x>1.234</x>
<y>5.678</y>
</location>
But the following is also valid:
<location>
<r>5.432</r>
<theta>31.97</theta>
</location>
This can be declared in a data description as follows:
<location dd:model="choice">
<dd:group>
<x/>
<y/>
</dd:group>
<dd:group>
<r/>
<theta/>
</dd:group>
</location>
Another use of
dd:group
is to provide a way to apply dd: attributes to groups of elements, again without
any corresponding element appearing in the data document. For example, the “polyline” element always
contains sets of coordinates. Each coordinate consists of an “x” element followed by a “y” element. There
must be at least two coordinates, but there is no maximum number. This can be declared in a data
description as follows: