iceberg::FieldProjection Struct Reference

A field schema partner to carry projection information. More...

#include <schema_util.h>

Classes
struct	ExtraAttributes
	Format-specific attributes for the field. For example, for Parquet it might store column id and level info of the projected leaf field. More...

Public Types
enum class	Kind {   kProjected , kMetadata , kConstant , kDefault ,   kNull }
	How the field is projected. More...
using	From = std::variant< std::monostate, size_t, Literal >
	A variant to indicate how to set the value of the field.

Public Attributes
Kind	kind
	The kind of projection of the field it partners with.
From	from
	The source to set the value of the field.
std::vector< FieldProjection >	children
	The children of the field if it is a nested field.
std::shared_ptr< ExtraAttributes >	attributes
	Format-specific attributes for the field.

Detailed Description

A field schema partner to carry projection information.

Member Typedef Documentation

From

using iceberg::FieldProjection::From = std::variant<std::monostate, size_t, Literal>

A variant to indicate how to set the value of the field.

Note

std::monostate is used to indicate that the field is not projected.

size_t is used to indicate the field index in the source schema on the same nesting level when kind is kProjected.

Literal is used to indicate the value of the field when kind is kConstant or kDefault.

Member Enumeration Documentation

Kind

enum class iceberg::FieldProjection::Kind

strong

How the field is projected.

Enumerator
kProjected	The field is projected from the source with possible conversion for supported schema evolution.
kMetadata	Metadata column whose value is generated on demand.
kConstant	The field is a constant value (e.g. partition field value)
kDefault	The field is missing in the source and should be filled with default value.
kNull	An optional field that is not present in the source.

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The documentation for this struct was generated from the following file:

• iceberg/schema_util.h