Unable to drop existing master table in sql developer - oracle

Question

I was using yeasterday many times Data Pump in Sql Developer Wizard to export and import data. After each export/import a new master table appeared under the "+" button in sql developer(view->dba).
I wanted to drop all this tables(about 10 tables) and I was successfull for all cases, except 2 of them. When I'm writing sql code: drop table x, it shows me error that this tables doesn't exists. It was working fine for every others tables..
When i run query select * from dba_tables where table_name='x' the table is there. I'm writing drop statement as system user.
select *
from dba_tables
where table_name in ('moj_dump_job'
, 'moj_job_data_pump');
OWNER TABLE_NAME
------------------------------ ------------------------------
SYSTEM moj_dump_job
SYSTEM moj_job_data_pump
drop table moj_dump_job;
Error starting at line : 1 in command -
drop table moj_dump_job
Error report -
ORA-00942: table or view does not exist
00942. 00000 - "table or view does not exist"
*Cause:
*Action:
I tired to drop this jobs, but it doesnt't work:
select owner_name, job_name
from DBA_DATAPUMP_JOBS;
OWNER_NAME JOB_NAME
------------------------------ ------------------------------
SYSTEM moj_job_data_pump
SYSTEM moj_dump_job
BEGIN
dbms_scheduler.drop_job(job_name => 'moj_dump_job');
END;
Error starting at line : 13 in command -
BEGIN
dbms_scheduler.drop_job(job_name => 'moj_dump_job');
END;
Error report -
ORA-27475: "SYSTEM.MOJ_DUMP_JOB" must be a job
ORA-06512: at "SYS.DBMS_ISCHED", line 213
ORA-06512: at "SYS.DBMS_SCHEDULER", line 657
ORA-06512: at line 2
27475. 00000 - "unknown %s \"%s\".\"%s\""
*Cause: The specified object did not exist, privileges were not granted,
or the object was of the wrong type.
*Action: Specify an object of the correct type on which you have privileges.
Do you have any idea what can I do? Using schema name before table name doesn't help.
Best regards, Darek

Answer 1

Thank's for your help. It work's.
drop table "moj_dump_job"
drop table "moj_job_data_pump";
Table "moj_dump_job" dropped.
Table "moj_job_data_pump" dropped.
Now
select *
from dba_tables
where table_name in ('moj_dump_job'
, 'moj_job_data_pump');
select owner_name, job_name
from DBA_DATAPUMP_JOBS;
Both statements doesn't return any rows. That's perfect, but the 2 tables are still visible under view ->dba ->data pump -> export jobs. How to drop them from the tree?

Answer 2

The reason it was not working cause by default Oracle changes job name to uppercase. To avoid it need use '"my_job"'
As per Oracle doc
Follow SQL naming rules to name Scheduler objects in the
DBMS_SCHEDULER package. By default, Scheduler object names are
uppercase unless they are surrounded by double quotes. For example,
when creating a job, job_name => 'my_job' is the same as job_name =>
'My_Job' and job_name => 'MY_JOB', but different from job_name =>
'"my_job"'. These naming rules are also followed in those cases where
comma-delimited lists of Scheduler object names are used within the
DBMS_SCHEDULER package.