org.apache.iceberg.orc

Class ORCSchemaUtil

java.lang.Object

org.apache.iceberg.orc.ORCSchemaUtil

public final class ORCSchemaUtil
extends java.lang.Object

Utilities for mapping Iceberg to ORC schemas.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ORCSchemaUtil.BinaryType
static class	ORCSchemaUtil.LongType

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	ICEBERG_BINARY_TYPE_ATTRIBUTE The name of the ORC TypeDescription attribute indicating the Iceberg type corresponding to an ORC binary type.
static java.lang.String	ICEBERG_LONG_TYPE_ATTRIBUTE The name of the ORC TypeDescription attribute indicating the Iceberg type corresponding to an ORC long type.

Method Summary

Modifier and Type	Method and Description
static org.apache.orc.TypeDescription	buildOrcProjection(Schema schema, org.apache.orc.TypeDescription originalOrcSchema) Converts an Iceberg schema to a corresponding ORC schema within the context of an existing ORC file schema.
static org.apache.orc.TypeDescription	convert(Schema schema)
static Schema	convert(org.apache.orc.TypeDescription orcSchema) Convert an ORC schema to an Iceberg schema.
static java.util.Map<java.lang.Integer,java.lang.String>	idToOrcName(Schema schema) Generates mapping from field IDs to ORC qualified names.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ICEBERG_BINARY_TYPE_ATTRIBUTE

public static final java.lang.String ICEBERG_BINARY_TYPE_ATTRIBUTE

The name of the ORC TypeDescription attribute indicating the Iceberg type corresponding to an ORC binary type. The values for this attribute are denoted in BinaryType.

See Also:

Constant Field Values

ICEBERG_LONG_TYPE_ATTRIBUTE

public static final java.lang.String ICEBERG_LONG_TYPE_ATTRIBUTE

The name of the ORC TypeDescription attribute indicating the Iceberg type corresponding to an ORC long type. The values for this attribute are denoted in LongType.

See Also:

Constant Field Values

Method Detail

convert

public static org.apache.orc.TypeDescription convert(Schema schema)

convert

public static Schema convert(org.apache.orc.TypeDescription orcSchema)

Convert an ORC schema to an Iceberg schema. This method handles the convertion from the original Iceberg column mapping IDs if present in the ORC column attributes, otherwise, ORC columns with no Iceberg IDs will be ignored and skipped in the conversion.

Returns:

the Iceberg schema

Throws:

java.lang.IllegalArgumentException - if ORC schema has no columns with Iceberg ID attributes

buildOrcProjection

public static org.apache.orc.TypeDescription buildOrcProjection(Schema schema,
                                                                org.apache.orc.TypeDescription originalOrcSchema)

Converts an Iceberg schema to a corresponding ORC schema within the context of an existing ORC file schema. This method also handles schema evolution from the original ORC file schema to the given Iceberg schema. It builds the desired reader schema with the schema evolution rules and pass that down to the ORC reader, which would then use its schema evolution to map that to the writer’s schema. Example: Iceberg writer ORC writer struct<a (1): int, b (2): string> struct<a: int, b: string> struct<a (1): struct<b (2): string, c (3): date>> struct<a: struct<b:string, c:date>> Iceberg reader ORC reader struct<a (2): string, c (3): date> struct<b: string, c: date> struct<aa (1): struct<cc (3): date, bb (2): string>> struct<a: struct<c:date, b:string>>

Parameters:

schema - an Iceberg schema

originalOrcSchema - an existing ORC file schema

Returns:

the resulting ORC schema

idToOrcName

public static java.util.Map<java.lang.Integer,java.lang.String> idToOrcName(Schema schema)

Generates mapping from field IDs to ORC qualified names. See IdToOrcName for details.