The sort direction. Valid values are asc for ascending order or desc for descending order.
asc
desc
Specifies how null values are ordered. Valid values are nulls-first to place nulls before non-null values, or nulls-last to place nulls after non-null values.
nulls-first
nulls-last
The ID of the source schema field to sort by. This must reference a valid field ID from the table schema.
The transform to apply to the source field before sorting. Use identity to sort by the field value directly, or specify other transforms as needed.
identity