Below code is running successfully.. but while I run second time it shows the message
ORA-31634 - job already exists
ERROR at line 1:
ORA-39001: invalid argument value
BEGIN
h1 := DBMS_DATAPUMP.OPEN('EXPORT','SCHEMA',NULL,'EXPORT18%U','LATEST');
DBMS_DATAPUMP.ADD_FILE(h1,'EXPORT18%U.dmp','EXPORT_DIR');
DBMS_DATAPUMP.METADATA_FILTER(h1,'SCHEMA_EXPR','IN (''SCHEMA_NAME1'')');
Dbms_Datapump.Metadata_Filter(handle => h1,name => 'NAME_EXPR',value => '!=''CALL_GROUP1_BASE_OLD''', object_type => 'TABLE');
DBMS_DATAPUMP.START_JOB(h1);
dbms_datapump.detach(h1);
END;
first time running successfully... what to do in second time.