# Structured data

<dl class="api-definition">
<dt>Concept</dt>
<dd><a href="/docs/development/opcua/client/structured-data">Structured data</a></dd>
</dl>

| Type | Description |
|---|---|
| [IOpcUnion](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.iopcunion/) | Defines that the implementing data type is to be treat like unions. |
| [OpcAutomatism](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcautomatism/) | Defines the behavior of global automatisms implemented in the OPC UA Framework Advanced. |
| [OpcClient](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/) | Provides session based methods to access OPC UA server services. |
| [OpcData](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdata/) | Defines an abstract base class of data objects used and provided in the ecosystem of a specific OPC UA Server. |
| [OpcDataField](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatafield/) | Represents a data field declared by the structured data type of a specific [OpcDataObject](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdataobject/) instance. |
| [OpcDataObject](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdataobject/) | Provides a generic and dynamically accessible representation of structured data types. |
| [OpcDataTypeAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypeattribute/) | Defines the identifier of a custom data type which is represented by the [Type](https://learn.microsoft.com/dotnet/api/system.type) on that this attribute is applied. |
| [OpcDataTypeEncodingAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypeencodingattribute/) | Defines the information about the encoding used for a custom data type which is represented by the [Type](https://learn.microsoft.com/dotnet/api/system.type) on that this attribute is applied. |
| [OpcDataTypeEncodingMaskAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypeencodingmaskattribute/) | Defines the size of the mask used to encode optional field information of the custom data type represented by the [Type](https://learn.microsoft.com/dotnet/api/system.type) on that this attribute is applied. |
| [OpcDataTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypeinfo/) | Represents type declarations used for data types. |
| [OpcDataTypeMemberSwitchAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypememberswitchattribute/) | Declares a field or property of a custom data type, to that the member belongs on that this attribute is applied, with conditional existence of the member within the stream of its custom data type. |
| [OpcDataTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypesystem/) | Represents an encoding-based system which is organized in type dictionaries to define type information to use to understand data exchanged via OPC UA using a specific type of encoding. |
| [OpcEncodingMaskKind](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcencodingmaskkind/) | Controls the definition and use of the 'EncodingMask' required in types with optional members. |
| [OpcMemberSwitchOperator](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmemberswitchoperator/) | Defines the operator to define how the value of a switch member is to be compared to a switch value to control the existence of the member to that the switch member applies. |
| [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) | Defines an identifier for a node in the address space of an OPC UA Server. |
| [OpcNodeSet](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeset/) | Provides a static in-memory representation of an address space including its nodes their references to each other and the used types. |
| [OpcRawObject](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrawobject/) | Represents the value of a structured data type which could not be decoded, as its sender encoded it. |
| [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) | Stores a value optionally associated with status and timestamp information. |