It looks like you need to create a semantic network, which creates all the system tables for storing RDF data (http://docs.oracle.com/database/122/RDFRM/SEM_APIS-reference.htm#RDFRM384)
You can be sure by checking for the MDSYS.RDF_VALUE$ table. DESC MDSYS.RDF_VALUE$. If that table does not exist, then a semantic network has not been created.
Sorry for late replay.
I execute command:
ORA-55321: Network already exists
Seems Network already exists.
And I checked MDSYS.RDF_VALUE$ table,
Columns can be seen and table exists.
Thanks for checking the RDF network. Looking back at your original error, it seems that the R2RML table cannot be found. r2rml_table_owner and r2rml_table_name arguments are case sensitive. Please try with r2rml_table_owner and r2rml_table_name input values fully capitalized.
Sorry for my late replay.
It was successful by changing owner and table_name into uppercase.
I don't know whether it is a bug or whatever.
By the way, thank you for reply!