The SimpleAttributeOperand is a simplified form of the AttributeOperand and all of the rules that apply to the AttributeOperand also apply to the SimpleAttributeOperand. The examples provided in B.1 only use AttributeOperand, however, the AttributeOperand can be replaced by a SimpleAttributeOperand whenever all ReferenceTypes in the RelativePath are subtypes of HierarchicalReferences and the targets are Object or Variable Nodes and an Alias is not required.

Table 133 defines the SimpleAttributeOperand type.

Table 133 – SimpleAttributeOperand






Attribute of a Node in the AddressSpace.



NodeId of a TypeDefinitionNode.

This parameter restricts the operand to instances of the TypeDefinitionNode or one of its subtypes.

If the SimpleAttributeOperand is used in an EventFilter and the typeDefinitionId is BaseEventType the Server shall evaluate the browsePath without considering the typeDefinitionId.

browsePath []


A relative path to a Node.

This parameter specifies a relative path using a list of BrowseNames instead of the RelativePath structure used in the AttributeOperand. The list of BrowseNames is equivalent to a RelativePath that specifies forward references which are subtypes of the HierarchicalReferences ReferenceType.

All Nodes followed by the browsePath shall be of the NodeClass Object or Variable.

If this list is empty the Node is the instance of the TypeDefinition.



Id of the Attribute. The IntegerId is defined in 7.19.

The Value Attribute shall be supported by all Servers. The support of other Attributes depends on requirements set in Profiles or other parts of this specification.



This parameter is used to identify a single element of an array, or a single range of indexes for an array. The array in this context includes String and ByteString. The first element is identified by index 0 (zero).

This parameter is ignored if the selected Node is not a Variable or the Value of a Variable is not an array.

All values in the array are used if this parameter is null or empty.

The NumericRange type is defined in 7.27.