Debug the procedure of "REVOKE" object privilege

Question

I creates two procedures, one for "GRANT ... on object" and other for "REVOKE.. from object".
# for GRANT
CREATE or REPLACE PROCEDURE grant_proc AS
own VARCHAR2(30);
nam VARCHAR2(30);
v_cur INTEGER;
cursor pkgs is
select ora_dict_obj_owner, ora_dict_obj_name from SYS.event_table;
begin
open pkgs;
loop
fetch pkgs into own, nam;
exit when pkgs%notfound;
v_cur := dbms_sql.open_cursor;
dbms_sql.parse(v_cur, 'GRANT SELECT ON ' || own || '.' ||nam|| ' to READ_BAANDB', dbms_sql.native);
dbms_sql.close_cursor(v_cur);
commit;
delete from sys.event_table;
commit;
end loop;
end;
# for REVOKE
CREATE or REPLACE PROCEDURE revoke_proc AS
own VARCHAR2(30);
nam VARCHAR2(30);
v_cur INTEGER;
cursor pkgs is
select ora_dict_obj_owner, ora_dict_obj_name from SYS.event_table;
begin
open pkgs;
loop
fetch pkgs into own, nam;
exit when pkgs%notfound;
v_cur := dbms_sql.open_cursor;
dbms_sql.parse(v_cur, 'REVOKE SELECT ON ' || own || '.' ||nam|| ' from READ_BAANDB', dbms_sql.native);
dbms_sql.close_cursor(v_cur);
commit;
delete from sys.event_table;
commit;
end loop;
end;
The problem is at the "delete from sys.event_table". The GRANT procedure works fine, but the same syntax in REVOKE procedure did not execute, despite the "REVOKE SELECT..." run ok. So how can I debug / write out any error from the step in the procedure?

Answer 1

It took me a while to remember how to write out the result of a query.
As you can see from the metalink note example which "GRANT SELECT... to user" when I created a table in the schema. And I added DROP event in the trigger and wrote my "REVOKE SELECT..from user" procedure similar to that of GRANT. So everytime when a table was CREATED or DROPPED from schema, system would return 1 rowcount of the event_table before the GRANT or REVOKE process run.
I also checked the total row count before and after both GRANT and REVOKE procedures in either trigger and in grant_job procedure, the total row count return from before and after is always 1 no matter whether is GRANT or REVOKE process. The end of trigger commits everything. However, only the GRANT commits completely, ie delete from sys.event_table; not the REVOKE section.
SQL> set serveroutput on
SQL> create table a1 (c number);
row count before: 1
row count after: 1
Table created.
SQL> select * from sys.event_table;
no rows selected
SQL> drop table a1;
row count before: 1
row count after: 1
Table dropped.
SQL> select * from sys.event_table;
ORA_DICT_OBJ_OWNER ORA_DICT_OBJ_NAME
BAANDB A1
Message was edited by:
CIATECPCV