Package io.delta.kernel.internal.util

Class ColumnMapping

Object

io.delta.kernel.internal.util.ColumnMapping

public class ColumnMapping
extends Object

Utilities related to the column mapping feature.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	COLUMN_MAPPING_ID_KEY
static final String	COLUMN_MAPPING_MODE_ID
static final String	COLUMN_MAPPING_MODE_KEY
static final String	COLUMN_MAPPING_MODE_NAME
static final String	COLUMN_MAPPING_MODE_NONE
static final String	COLUMN_MAPPING_PHYSICAL_NAME_KEY
static final String	PARQUET_FIELD_ID_KEY

Method Summary

Modifier and Type	Method	Description
static StructType	convertToPhysicalSchema(StructType logicalSchema, StructType physicalSchema, String columnMappingMode)	Helper method that converts the logical schema (requested by the connector) to physical schema of the data stored in data files based on the table's column mapping mode.
static String	getColumnMappingMode(Map<String,String> configuration)	Returns the column mapping mode from the given configuration.
static String	getPhysicalName(StructField field)	Returns the physical name for a given StructField
static void	throwOnUnsupportedColumnMappingMode(Metadata metadata)	Checks if the given column mapping mode in the given table metadata is supported.

Methods inherited from class java.lang.Object

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

Field Details

COLUMN_MAPPING_MODE_KEY

public static final String COLUMN_MAPPING_MODE_KEY

See Also:

• Constant Field Values

COLUMN_MAPPING_MODE_NONE

public static final String COLUMN_MAPPING_MODE_NONE

See Also:

• Constant Field Values

COLUMN_MAPPING_MODE_NAME

public static final String COLUMN_MAPPING_MODE_NAME

See Also:

• Constant Field Values

COLUMN_MAPPING_MODE_ID

public static final String COLUMN_MAPPING_MODE_ID

See Also:

• Constant Field Values

COLUMN_MAPPING_PHYSICAL_NAME_KEY

public static final String COLUMN_MAPPING_PHYSICAL_NAME_KEY

See Also:

• Constant Field Values

COLUMN_MAPPING_ID_KEY

public static final String COLUMN_MAPPING_ID_KEY

See Also:

• Constant Field Values

PARQUET_FIELD_ID_KEY

public static final String PARQUET_FIELD_ID_KEY

See Also:

• Constant Field Values

Method Details

getColumnMappingMode

public static String getColumnMappingMode(Map<String,String> configuration)

Returns the column mapping mode from the given configuration.

Parameters:

configuration - Configuration

Returns:

Column mapping mode. One of ("none", "name", "id")

throwOnUnsupportedColumnMappingMode

public static void throwOnUnsupportedColumnMappingMode(Metadata metadata)

Checks if the given column mapping mode in the given table metadata is supported. Throws on unsupported modes.

Parameters:

metadata - Metadata of the table

convertToPhysicalSchema

public static StructType convertToPhysicalSchema(StructType logicalSchema,
 StructType physicalSchema,
 String columnMappingMode)

Helper method that converts the logical schema (requested by the connector) to physical schema of the data stored in data files based on the table's column mapping mode.

Parameters:

logicalSchema - Logical schema of the scan

physicalSchema - Physical schema of the scan

columnMappingMode - Column mapping mode

getPhysicalName

public static String getPhysicalName(StructField field)

Returns the physical name for a given StructField