The OPC UA ContentFilterElement. 更多...
import 语句: | import QtOpcUa |
Since: | QtOpcUa 5.13 |
A content filter element contains an operator and operands. There are four different operator types which contain literal values, references to attributes of nodes or to other content filter elements.
A combination of one or more content filter elements makes a content filter which is used by the server to filter data for the criteria defined by the content filter elements. For example, the
where
clause of an event filter is a content filter which is used to decide if a notification is generated for an event.
QtOpcUa.FilterElement { operator: QtOpcUa.FilterElement.GreaterThanOrEqual firstOperand: QtOpcUa.SimpleAttributeOperand { ... } secondOperand: QtOpcUa.LiteralOperand { ... } }
另请参阅 EventFilter .
firstOperand : variant |
First operand to be used with the operator. This can be one of SimpleAttributeOperand , AttributeOperand , LiteralOperand or ElementOperand .
operatorType : enumeration |
The filter operator.
Possible operators for a FilterElement that are specified in OPC UA 1.05 part 4, 7.7.3
常量 | 值 |
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FilterElement.Equals
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FilterElement.IsNull
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FilterElement.GreaterThan
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FilterElement.LessThan
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FilterElement.GreaterThanOrEqual
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FilterElement.LessThanOrEqual
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FilterElement.Like
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FilterElement.Not
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FilterElement.Between
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FilterElement.InList
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FilterElement.And
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FilterElement.Or
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FilterElement.Cast
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FilterElement.InView
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FilterElement.OfType
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FilterElement.RelatedTo
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FilterElement.BitwiseAnd
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FilterElement.BitwiseOr
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secondOperand : variant |
Second operand to be used with the operator. This can be one of SimpleAttributeOperand , AttributeOperand , LiteralOperand or ElementOperand .