Package io.delta.kernel.internal.types

Class TypeWideningChecker

Object
io.delta.kernel.internal.types.TypeWideningChecker
public class TypeWideningChecker extends Object
Utility class for checking type widening compatibility according to the Delta protocol.

The Type Widening feature enables changing the type of a column or field in an existing Delta table to a wider type. This class implements the checks required by the protocol to ensure that only supported type changes are allowed.

Supported type changes as per protocol:

  • Integer widening: Byte -> Short -> Int -> Long
  • Floating-point widening: Float -> Double
  • Floating-point widening: Byte, Short or Int -> Double
  • Date widening: Date -> Timestamp without timezone
  • Decimal widening: Decimal(p, s) -> Decimal(p + k1, s + k2) where k1 >= k2 >= 0
  • Decimal widening: Byte, Short or Int -> Decimal(10 + k1, k2) where k1 >= k2 >= 0
  • Decimal widening: Long -> Decimal(20 + k1, k2) where k1 >= k2 >= 0

  • Method Details

    • isWideningSupported

      public static boolean isWideningSupported(DataType sourceType, DataType targetType)
      Checks if a type change from sourceType to targetType is a supported widening operation.
      Parameters:
      sourceType - The original data type
      targetType - The target data type to widen to
      Returns:
      true if the type change is a supported widening operation (or the types are equal), false otherwise

    • isIcebergV2Compatible

      public static boolean isIcebergV2Compatible(DataType sourceType, DataType targetType)
      Checks if the type change is supported by Iceberg V2 schema evolution. This is required when Iceberg compatibility is enabled.
      Parameters:
      sourceType - The original data type
      targetType - The target data type to widen to
      Returns:
      true if the type change is supported by Iceberg V2 (sourceType == targetType returns true), false otherwise