FileSourceConstantMetadataAttribute¶

Creating Metadata AttributeReference¶

apply(
  name: String,
  dataType: DataType,
  nullable: Boolean = false): AttributeReference

apply creates an AttributeReference with the following metadata:

Metadata Key	Value
__metadata_col	`true`
__file_source_metadata_col	`true`
__file_source_constant_metadata_col	`true`

apply is used when:

FileSourceStrategy execution planning strategy is executed (to plan a LogicalRelation over a HadoopFsRelation)