Module metadata_columns

Metadata columns (virtual/reserved fields) for Iceberg tables.

This module defines metadata columns that can be requested in projections but are not stored in data files. Instead, they are computed on-the-fly during reading. Examples include the _file column (file path) and future columns like partition values or row numbers.

Constants

RESERVED_COL_DOC_FILE

Documentation for the _file metadata column

RESERVED_COL_NAME_FILE

Reserved column name for the file path metadata column

RESERVED_FIELD_ID_FILE

Reserved field ID for the file path (_file) column per Iceberg spec

Functions

file_field

Returns the Iceberg field definition for the _file metadata column.

get_metadata_field

Returns the Iceberg field definition for a metadata field ID.

get_metadata_field_id

Returns the field ID for a metadata column name.

is_metadata_column_name

Checks if a column name is a metadata column.

is_metadata_field

Checks if a field ID is a metadata field.