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Annotations
Attributes
Diagrams
Source
Used by
Complex Type gml:AssociationType
Namespace http://www.opengis.net/gml
Annotations
A pattern or base for derived types used to specify complex types corresponding to an  unspecified UML association - either composition or aggregation.  Restricts the cardinality of Objects contained in the association to a maximum of one.  An instance of this type can contain an element representing an Object, or serve as a pointer to a remote Object.  

Descendents of this type can be restricted in an application schema to 
* allow only specified classes as valid participants in the aggregation
* allow only association by reference (i.e. empty the content model) or by value (i.e. remove the xlinks).    

When used for association by reference, the value of the gml:remoteSchema attribute can be used to locate a schema fragment that constrains the target instance.   

In many cases it is desirable to impose the constraint prohibiting the occurence of both reference and value in the same instance, as that would be ambiguous.  This is accomplished by adding a directive in the annotation element of the element declaration.  This directive can be in the form of normative prose, or can use a Schematron pattern to automatically constrain co-occurrence - see the declaration for _strictAssociation below.   

If co-occurence is not prohibited, then both a link and content may be present.  If this occurs in an instance, then the rule for interpretation is that the instance found by traversing the href provides the normative value of the property, and should be used when possible.  The value(s) included as content may be used if the remote instance cannot be resolved.  This may be considered to be a "cached" version of the value(s).
Diagram
Diagram docindex1.tmp#id36 docindex42.tmp#id195
Used by
Model gml:_Object
Children gml:_Object
Attributes
QName Type Fixed Default Use Annotation
gml:remoteSchema anyURI optional
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the XML Schema Section 4.14 Referencing Schemas from Elsewhere.
xlink:actuate restriction of string optional
The 'actuate' attribute is used to communicate the desired timing 
of traversal from the starting resource to the ending resource; 
it's value should be treated as follows:
onLoad - traverse to the ending resource immediately on loading 
         the starting resource 
onRequest - traverse from the starting resource to the ending 
            resource only on a post-loading event triggered for 
            this purpose 
other - behavior is unconstrained; examine other markup in link 
        for hints 
none - behavior is unconstrained
xlink:arcrole anyURI optional
xlink:href anyURI optional
xlink:role anyURI optional
xlink:show restriction of string optional
The 'show' attribute is used to communicate the desired presentation 
of the ending resource on traversal from the starting resource; it's 
value should be treated as follows: 
new - load ending resource in a new window, frame, pane, or other 
      presentation context
replace - load the resource in the same window, frame, pane, or 
          other presentation context
embed - load ending resource in place of the presentation of the 
        starting resource
other - behavior is unconstrained; examine other markup in the 
        link for hints 
none - behavior is unconstrained
xlink:title string optional
xlink:type string simple optional
Source
<complexType name="AssociationType">
  <annotation>
    <documentation>A pattern or base for derived types used to specify complex types corresponding to an unspecified UML association - either composition or aggregation. Restricts the cardinality of Objects contained in the association to a maximum of one. An instance of this type can contain an element representing an Object, or serve as a pointer to a remote Object. Descendents of this type can be restricted in an application schema to * allow only specified classes as valid participants in the aggregation * allow only association by reference (i.e. empty the content model) or by value (i.e. remove the xlinks). When used for association by reference, the value of the gml:remoteSchema attribute can be used to locate a schema fragment that constrains the target instance. In many cases it is desirable to impose the constraint prohibiting the occurence of both reference and value in the same instance, as that would be ambiguous. This is accomplished by adding a directive in the annotation element of the element declaration. This directive can be in the form of normative prose, or can use a Schematron pattern to automatically constrain co-occurrence - see the declaration for _strictAssociation below. If co-occurence is not prohibited, then both a link and content may be present. If this occurs in an instance, then the rule for interpretation is that the instance found by traversing the href provides the normative value of the property, and should be used when possible. The value(s) included as content may be used if the remote instance cannot be resolved. This may be considered to be a "cached" version of the value(s).</documentation>
  </annotation>
  <sequence minOccurs="0">
    <element ref="gml:_Object"/>
  </sequence>
  <attributeGroup ref="gml:AssociationAttributeGroup"/>
</complexType>
Schema location http://schemas.opengis.net/gml/3.1.1/base/gmlBase.xsd