The DBA_PART_KEY_COLUMNS view provides information about the key columns of the partitioned tables that reside in the database.

ownerTEXTThe owner of the table.
schema_nameTEXTThe name of the schema in which the table resides.
nameTEXTThe name of the table in which the column resides.
object_typeCHARACTER(5)For compatibility only; always TABLE.
column_nameTEXTThe name of the column on which the key is defined.
column_positionINTEGER1 for the first column; 2 for the second column, etc.