field¶

Canonical path: o6.field

field ¶

field(
    *,
    name=None,
    description=None,
    isOptional=False,
    valueRank=None,
    arrayDimensions=None,
    maxStringLength=None
)

Attach OPC UA metadata to an annotated DataType field.

Used as the assigned value of an annotated attribute in a @o6.datatype class body. The annotation still supplies the field's static type, so this factory deliberately returns Any to type checkers and adds only what the annotation cannot express.

@o6.datatype(ns="plant")
class BatchRecord:
    batchId: str
    comment: Optional[str] = o6.field(description="free-text operator note")
    tag: str = o6.field(maxStringLength=32)

Parameters:

Name	Type	Description	Default
`name`	`Optional[str]`	OPC UA field name. This renames the Python attribute along with the wire field, so it is mainly useful when a UA field name is not a valid Python identifier.	`None`
`description`	`Optional[str]`	The field's Description in the `StructureDefinition`.	`None`
`isOptional`	`bool`	Mark the field optional. `Optional[T]` in the annotation does the same thing and is the form to prefer.	`False`
`valueRank`	`Optional[int]`	Override the rank inferred from the annotation. Structure members must be scalars (`-1`) or 1-D arrays (`1`); anything else is rejected, because open62541 cannot represent a multi-dimensional array as a structure member.	`None`
`arrayDimensions`	`Optional[list[int]]`	ArrayDimensions of the field.	`None`
`maxStringLength`	`Optional[int]`	Length hint for a `String` or `ByteString` field.	`None`

See Field metadata with o6.field.