Using all_tab_cols from a procedure

Question

I have a custom made procedure in my schema that should retrieve columns of a table based on the user that calls the procedure.
I'm using "all_tab_cols" view in a procedure. Here is the query from the USER_A.MY_PROCEDURE :
SELECT LOWER(column_name) column_name,
DECODE (data_type, 'VARCHAR2', 'C', 'CHAR', 'C', 'LONG', 'C', 'NUMBER', 'N', 'DATE', 'D') data_type
FROM all_tab_cols
WHERE table_name = UPPER('my_table')
AND owner = 'USER_B'
ORDER BY column_id;
When i run this query from Toad as USER_A, it works. However when i run it as USER_B from a procedure (exec USER_A.MY_PROCEDURE) it doesn't return any row. I guess there is something with permissions, but i cannot figure out what.
What are the permissions that should be set for this to work?

Answer 1

I don't believe you!
You should post the exact code you have
Look at this:
SQL> connect / as sysdba
Connected.
SQL> create user user_a identified by user_a
  2  default tablespace gen_ts_adhoc
  3  temporary tablespace gen_ts_temp_adhoc
  4  /
User created.
SQL> create user  user_b identified by user_b
  2  default tablespace gen_ts_adhoc
  3  temporary tablespace gen_ts_temp_adhoc
  4  /
User created.
SQL> grant create session, alter session to user_a;
Grant succeeded.
SQL> grant create session, alter session to user_b;
Grant succeeded.
SQL> grant create table to user_b;
Grant succeeded.
SQL> alter user user_b quota 10m on gen_ts_adhoc;
User altered.
SQL> grant create procedure to user_a;
Grant succeeded.No we have the two users you are talking of: user_a and user_b
We now create the table MY_TABLE in the user_b schema:
SQL> connect user_b/user_b
Connected.
SQL> create table my_table ( c1 number, c2 varchar2(30), c3 date);
Table created.
SQL> grant select on my_table to user_a;
Grant succeeded.We then create the procedure MY_PROCEDURE in the user_a schema
SQL> connect user_a/user_a
Connected.
SQL> create or replace procedure my_procedure as
  2  begin
  3    for rec in (
  4                 SELECT LOWER(column_name) column_name,
  5                 DECODE (data_type, 'VARCHAR2', 'C', 'CHAR', 'C', 'LONG', 'C', 'NUMBER', 'N', 'DATE', 'D') data_type
  6                 FROM all_tab_cols
  7                 WHERE table_name = UPPER('my_table')
  8                 AND owner = 'USER_B'
  9                 ORDER BY column_id   -- this is exactly a copy/paste of your select statement
10               ) loop
11       dbms_output.put_line('Column: ' || rec.column_name);
12    end loop;
13  end;
14  /
Procedure created.
SQL> set serveroutput on
SQL> exec my_procedure;
Column: c1
Column: c2
Column: c3
PL/SQL procedure successfully completed.
This is nicely working (as you wrote)SQL> grant execute on my_procedure to user_b;
Grant succeeded.
SQL> connect user_b/user_b
Connected.
SQL> exec user_a.my_procedure;
Column: c1
Column: c2
Column: c3
PL/SQL procedure successfully completed.
SQL>
And this is also nicely working!
So there must be something you did not tell us or you did not really do a copy/paste