This structure contains elements that describe changes of the model. Its composition is defined in Table 156.
Table 156 – ModelChangeStructureDataType Structure
|affected||NodeId||NodeId of the Node that was changed. The client should assume that the affected Node has been created or deleted, had a Reference added or deleted, or the DataType has changed as described by the verb.|
|affectedType||NodeId||If the affected Node was an Object or Variable, affectedType contains the NodeId of the TypeDefinitionNode of the affected Node. Otherwise it is set to null.|
|verb||Byte||Describes the changes happening to the affected Node.
The verb is an 8-bit unsigned integer used as bit mask with the structure defined in the following table:
Field Bit Description
NodeAdded 0 Indicates the affected Node has been added.
NodeDeleted 1 Indicates the affected Node has been deleted.
ReferenceAdded 2 Indicates a Reference has been added. The affected Node may be either a SourceNode or TargetNode. Note that an added bidirectional Reference is reflected by two changes.
ReferenceDeleted 3 Indicates a Reference has been deleted. The affected Node may be either a SourceNode or TargetNode. Note that a deleted bidirectional Reference is reflected by two changes.
DataTypeChanged 4 This verb may be used only for affected Nodes that are Variables or VariableTypes. It indicates that the DataType Attribute has changed.
Reserved 5:7 Reserved for future use. Shall always be zero.
A verb may identify several changes on the affected Node at once. This feature should be used if event compression is used (see OPC 10000-3 for details).
Note that all verbs shall always be considered in the context where the ModelChangeStructureDataType is used. A NodeDeleted may indicate that a Node was removed from a view but still exists in other Views.
Its representation in the AddressSpace is defined in Table 157.
Table 157 – ModelChangeStructureDataType Definition