UA Part 14: PubSub - A.1 DataType Schema Header Structures

This Structure DataType is the abstract base type used to provide OPC UA DataType definitions for an OPC UA Binary encoded byte blob used outside an OPC UA Server AddressSpace.

The DataTypeSchemaHeader is formally defined in Table A.1.

Table A.1 – DataTypeSchemaHeader Structure

Name	Type	Description
DataTypeSchemaHeader	Structure
namespaces	String[]	Defines an array of namespace URIs. The index into the array is referred to as NamespaceIndex. The NamespaceIndex is used in NodeIds and QualifiedNames, rather than the longer namespace URI. NamespaceIndex 0 is reserved for the OPC UA namespace and it is not included in this array. The array contains the namespaces used in the data that follows the DataTypeSchemaHeader. The index used in NodeId and QualifiedNames identify an element in this list. The first entry in this array maps to NamespaceIndex 1.
structureDataTypes	StructureDescription[]	Description of Structure and Union DataTypes used in the data that follows the DataTypeSchemaHeader. This includes nested Structures. DataType NodeIds for Structure DataTypes used in the data refer to entries in this array. The StructureDescription DataType is defined in A.1.3.
enumDataTypes	EnumDescription[]	Description of Enumeration or OptionSet DataTypes used in in the data that follows the DataTypeSchemaHeader. DataType NodeIds for Enumeration or OptionSet DataTypes used in the data refer to entries in this array. The EnumDescription DataType is defined in A.1.4.
simpleDataTypes	SimpleTypeDescription[]	Description of DataTypes derived from built-in DataTypes. This excludes OptionSet DataTypes.

The DataTypeSchemaHeader Structure representation in the AddressSpace is defined in Table A.2.

Table A.2 – DataTypeSchemaHeader Definition

Attributes	Value
BrowseName	DataTypeSchemaHeader
IsAbstract	True
References	NodeClass	BrowseName	IsAbstract
Subtype of Structure defined in OPC 10000-5.
HasSubtype	DataType	UABinaryFileDataType	False

A.1.2 DataTypeDescription

This Structure DataType is the abstract base type for all DataType descriptions containing the DataType NodeId and the definition for custom DataTypes like Structures and Enumerations. The DataTypeDescription is formally defined in Table A.3.

Table A.3 – DataTypeDescription Structure

Name	Type	Description
DataTypeDescription	Structure
dataTypeId	NodeId	The NodeId of the DataType.
name	QualifiedName	A unique name for the data type.

The DataTypeDescription Structure representation in the AddressSpace is defined in Table A.4.

Table A.4 – DataTypeDescription Definition

Attributes	Value
BrowseName	DataTypeDescription
IsAbstract	True
References	NodeClass	BrowseName	IsAbstract
Subtype of Structure defined in OPC 10000-5.
HasSubtype	DataType	StructureDescription	FALSE
HasSubtype	DataType	EnumDescription	FALSE

A.1.3 StructureDescription

This Structure DataType provides the concrete DataTypeDescription for Structure DataTypes. It is a subtype of the DataTypeDescription DataType. The StructureDescription is formally defined in Table A.5.

Table A.5 – StructureDescription Structure

Name	Type	Description
StructureDescription	Structure
structureDefinition	StructureDefinition	The definition of the structure DataType. The StructureDefinition DataType is defined in OPC 10000-3.

Its representation in the AddressSpace is defined in Table A.6.

Table A.6 – StructureDescription Definition

Attributes	Value
BrowseName	StructureDescription
IsAbstract	False
Subtype of DataTypeDescription defined in 6.2.2.1.5.

A.1.4 EnumDescription

This Structure DataType provides the concrete DataTypeDescription for Enumeration DataTypes. It is a subtype of the DataTypeDescription DataType. The EnumDescription is formally defined in Table A.7.

Table A.7 – EnumDescription Structure

Name	Type	Description
EnumDescription	Structure
enumDefinition	EnumDefinition	The definition of the enumeration DataType. The EnumDefinition DataType is defined in OPC 10000-3.
builtInType	Byte	The builtInType indicates if the DataType is an Enumeration or an OptionSet. If the builtInType is Int32, the DataType is an Enumeration. If the builtInType is one of the UInteger DataTypes or ExtensionObject, the DataType is an OptionSet.

Its representation in the AddressSpace is defined in Table A.8.

Table A.8 – EnumDescription Definition

Attributes	Value
BrowseName	EnumDescription
IsAbstract	False
Subtype of DataTypeDescription defined in 6.2.2.1.5.

A.1.5 SimpleTypeDescription

This Structure DataType provides the information for DataTypes derived from built-in DataTypes. It is a subtype of Structure. The SimpleTypeDescription is formally defined in Table A.9.

Table A.9 – SimpleTypeDescription Structure

Name	Type	Description
SimpleTypeDescription	Structure
baseDataType	NodeId	The base DataType of the simple DataType.
builtInType	Byte	The builtInType used for the encoding of the simple DataType.