DeltaColumnMappingMode¶

DeltaColumnMappingMode is an abstraction of the column mapping modes in Column Mapping.

Contract¶

Name¶

name: String

Human-friendly name of this DeltaColumnMappingMode (for error reporting)

Used when:

• DeltaErrors utility is used to create a DeltaColumnMappingUnsupportedException and a ColumnMappingException (for missingColumnId, missingPhysicalName, duplicatedColumnId, duplicatedPhysicalName)
• DeltaColumnMappingBase is requested to verifyAndUpdateMetadataChange, getColumnMappingMetadata and createPhysicalSchema

Implementations¶

IdMapping¶

This mode uses the column ID as the identifier of a column.

Name: id

Used for tables converted from Apache Iceberg.

This mode requires a new protocol

NameMapping¶

Name: name

NameMapping is the only allowed mapping mode change (from NoMapping)

This mode requires a new protocol

NameMapping is among the supportedModes

NameMapping is used when:

• DeltaColumnMappingBase is requested for the column mapping metadata, tryFixMetadata, getPhysicalNameFieldMap

NoMapping¶

No column mapping and the display name of a column is the only valid identifier to read and write data.

Name: none

This mode does not require a new protocol

NoMapping is among the supportedModes

Creating DeltaColumnMappingMode¶

apply(
  name: String): DeltaColumnMappingMode

apply returns the DeltaColumnMappingMode for the given name (if defined) or throws a ColumnMappingUnsupportedException:

The column mapping mode `[mode]` is not supported for this Delta version.
Please upgrade if you want to use this mode.

apply is used when:

• DeltaConfigsBase is requested to build delta.columnMapping.mode configuration property