Use the CREATE_EXTERNAL_TABLE procedure with the format option Strict Column Order

Use the DBMS_CLOUD.CREATE_EXTERNAL_TABLE procedure to create implicit partitioned external tables.

By passing the appropriate options to this procedure, the partitions are derived from the source data. The partitioned external tables support runtime discovery of partition columns and their values. Runtime discovery of changes in the underlying object store structure, such as adding or removing objects, simplifies the maintenance process by eliminating the need for additional synchronization procedures required by DBMS_CLOUD.CREATE_EXTERNAL_PART_TABLE. This ensures that the data is up to date at query runtime.

See Query External Tables with Implicit Partitioning for more information.