Package org.apache.calcite.rel.metadata

Interface BuiltInMetadata.ColumnOrigin

All Superinterfaces:
Metadata
Enclosing class:
BuiltInMetadata
public static interface BuiltInMetadata.ColumnOrigin extends Metadata
Metadata about the origins of columns.

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static interface 
    BuiltInMetadata.ColumnOrigin.Handler
    Handler API.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final MetadataDef<BuiltInMetadata.ColumnOrigin>
    DEF
     

  • Method Summary

    Modifier and Type
    Method
    Description
    @Nullable Set<RelColumnOrigin>
    getColumnOrigins(int outputColumn)
    For a given output column of an expression, determines all columns of underlying tables which contribute to result values.

    Methods inherited from interface org.apache.calcite.rel.metadata.Metadata

    rel

  • Field Details

  • Method Details

    • getColumnOrigins

      @Nullable Set<RelColumnOrigin> getColumnOrigins(int outputColumn)
      For a given output column of an expression, determines all columns of underlying tables which contribute to result values. An output column may have more than one origin due to expressions such as Union and LogicalProject. The optimizer may use this information for catalog access (e.g. index availability).
      Parameters:
      outputColumn - 0-based ordinal for output column of interest
      Returns:
      set of origin columns, or null if this information cannot be determined (whereas empty set indicates definitely no origin columns at all)