HashColumnSpec

final class lsst.daf.butler.column_spec.HashColumnSpec(*, name: str, doc: str = '', type: Literal['hash'] = 'hash', nullable: bool = True, nbytes: int)

Bases: _BaseColumnSpec

Description of a hash digest.

Attributes Summary

model_computed_fields	A dictionary of computed field names and their corresponding ComputedFieldInfo objects.
model_config	Configuration for the model, should be a dictionary conforming to [ConfigDict][pydantic.config.ConfigDict].
model_fields	Metadata about the fields defined on the model, mapping of field names to [FieldInfo][pydantic.fields.FieldInfo].

Methods Summary

to_arrow()	Return an object that converts values of this column to a column in an Arrow table.
to_sql_spec([name_shrinker])	Convert this specification to a SQL-specific one.

Attributes Documentation

model_computed_fields: ClassVar[dict[str, ComputedFieldInfo]] = {}

A dictionary of computed field names and their corresponding ComputedFieldInfo objects.

model_config: ClassVar[ConfigDict] = {}

Configuration for the model, should be a dictionary conforming to [ConfigDict][pydantic.config.ConfigDict].

model_fields: ClassVar[dict[str, FieldInfo]] = {'doc': FieldInfo(annotation=str, required=False, default='', description='Documentation for the column.'), 'name': FieldInfo(annotation=str, required=True, description='Name of the column.'), 'nbytes': FieldInfo(annotation=int, required=True), 'nullable': FieldInfo(annotation=bool, required=False, default=True, description='Whether the column may be ``NULL``.'), 'type': FieldInfo(annotation=Literal['hash'], required=False, default='hash')}

Metadata about the fields defined on the model, mapping of field names to [FieldInfo][pydantic.fields.FieldInfo].

This replaces Model.__fields__ from Pydantic V1.

Methods Documentation

to_arrow() → ToArrow

Return an object that converts values of this column to a column in an Arrow table.

Returns:

converterarrow_utils.ToArrow

A converter object with schema information in Arrow form.

to_sql_spec(name_shrinker: NameShrinker | None = None, **kwargs: Any) → ddl.FieldSpec

Convert this specification to a SQL-specific one.

Parameters:

name_shrinkerNameShrinker, optional

Object that should be used to shrink the field name to ensure it fits within database-specific limits.

**kwargs

Forwarded to ddl.FieldSpec.

Returns:

sql_specddl.FieldSpec

A SQL-specific version of this specification.