Projecting Objects to XML Specifying Namespaces for Elements and Attributes [Home] [Back] [Next]

• Overview
• How to specify the namespace for top-level objects
• How to specify the namespace for properties projected as elements
• How to specify the namespaces for properties projected as attributes
• How to specify custom prefixes for namespaces
• Recommendations

• Qualified, which means that the element or attribute is in the target namespace of the schema.
• Unqualified, which has different meaning for elements and attributes. An unqualified element is in no namespace. An unqualified attribute is in the default namespace, if any, of its containing element.

• The <schema> element can specify the elementFormDefault and attributeFormDefault attributes. This controls the default namespace assignment of any elements and attributes in the schema. The possible values are "qualified" and "unqualified".
  These attributes are optional. The default for both of them is "unqualified". That is, by default if a element or attribute is used without a prefix, it is in no namespace.
• Second, the definition of an element or attribute can specify the form attribute, which indicates how that item is assigned to a namespace. The possible values are "qualified" and "unqualified".

<?xml version="1.0" encoding="UTF-8"?>
<ClassA xmlns="mynamespace" xmlns:s01="mynamespace" s01:String1="abcdef">
  <s01:ClassB xmlns="">
    <String3>qrstuv</String3>
    <String4>wxyz</String4>
  </s01:ClassB>
  <String2>ghijkl</String2>
</ClassA>

• The <ClassA> element is in mynamespace, because of two items:
  • That is the namespace given by the default namespace declaration for this element and its immediate children (xmlns="mynamespace").
  • The <ClassA> element does not have a namespace prefix that would indicate some other namespace.
• The String1 attribute is in mynamespace, because this attribute uses the s01 prefix, and the xmlns:s01 namespace declaration indicates that the s01 refers to the mynamespace namespace.
  Because the schema uses the default for attributeFormDefault ("unqualified"), the String1 attribute would be in mynamespace even if it did not use a namespace prefix.
• The <ClassB> element is in mynamespace, because this attribute uses the s01 prefix.
• The <String3> and <String4> elements are not in any namespace, because of two items:
  • The namespace declaration for the parent element indicates that the default namespace here is null (xmlns="").
  • These elements do not have a namespace prefix that would indicate some other namespace.
• The element <String2> is the namespace mynamespace, because that is the default namespace specified in its parent element.

• If the NAMESPACE parameter of the class is specified, the element is assigned to that namespace.
• If the NAMESPACE parameter of the class is not specified, the element does not belong to any namespace. You can, however, specify a namespace during export. See “Writing XML Output from Caché Objects” in Using Caché XML Tools.

Class MyApp.Person Extends (%Persistent, %XML.Adaptor)
{
Parameter NAMESPACE = "http://www.person.org";

Property Name As %Name [ Required ];

Property DOB As %Date(FORMAT = 5, MAXVAL = "+$h") [ Required ];
}

<Person xmlns="http://www.person.org">
  <Name>Isaacs,Rob G.</Name>
  <DOB>1981-01-29</DOB>
</Person>

• If the ELEMENTQUALIFIED class parameter is 1 for the parent class, the local elements are qualified, and they are explicitly included in namespace of their parent element.
  
• If the ELEMENTQUALIFIED class parameter is 0 for the parent class, the local elements are unqualified, and they do not belong to any namespace. (You can, however, specify a namespace during export. See “Writing XML Output from Caché Objects” in Using Caché XML Tools.)
  

1. If the REFNAMESPACE property parameter is specified, the element is in that namespace.
   
2. Otherwise the element is assigned to a namespace as follows:
   1. If the property is a type and specifies the XSDTYPE class parameter, the element is in the namespace of the parent class.
   2. Otherwise, if the property class defines the NAMESPACE class parameter, the element is in the namespace of the property class.
   3. If the property class does not define either of these class parameters, the element is in no namespace.
   

• 0 (the default), which means that no namespace prefix is included.
• 1, which means that a namespace prefix is included.

1. If the REFNAMESPACE property parameter is specified, the attribute is in that namespace.
2. Otherwise:
   1. If the property is a type and specifies the XSDTYPE class parameter, the attribute is in the namespace of the parent class.
   2. Otherwise, if the property class defines the NAMESPACE class parameter, the attribute is in the namespace of the property class.
   3. If the property class does not define either of these class parameters, the attribute is in no namespace.

• It ensures that the prefix you specify is declared in the XML output. That is, it is declared even if doing so is not necessary.
• It uses that prefix rather than the automatically generated prefix that you would otherwise see.

Class GXML.Person Extends (%Persistent, %XML.Adaptor)
{

Parameter XMLPREFIX = "p";

Parameter NAMESPACE = "http://www.person.com";

Parameter XMLNAME = "Person";

Property Name As %Name;

}

<?xml version="1.0" encoding="UTF-8"?>
<Person xmlns="http://www.person.com" xmlns:p="http://www.person.com">
  <Name>Umansky,Jocelyn O.</Name>
</Person>

• If you need to specify namespaces, specify NAMESPACE in all your XML-enabled classes. Otherwise, the defaulting rules become complex.
• If you need to control whether local elements are qualified, also specify the ELEMENTQUALIFIED parameter in all your XML-enabled classes.