PLSQL : ORA-14551: cannot perform a DML operation inside a query - oracle

Question

I went through some of the already answered questions, mentioned below, but could not find a solution that worked for me.
ORA-14551: cannot perform a DML operation inside a query
ORA-14551: cannot perform a DML operation inside a query error while using Execute immediate
I have written this within a function, that I am calling from a procedure.
OPEN c_rules_details;
LOOP
FETCH c_rules_details INTO rule_conditions_record;
EXIT WHEN c_rules_details %notfound;
dbms_output.put_line('Range and rule is '|| rule_conditions_record.rdr_tmplt_id || rule_conditions_record.rdr_rng_from ||rule_conditions_record.rdr_rng_to);
SELECT COUNT(*) INTO v_balance_records FROM t_scb_temp_objects WHERE RULE_CONDITION=rule_conditions_record.rdr_tmplt_id AND CHARGE is NULL;
dbms_output.put_line('Number of records in rule are '|| v_balance_records);
IF v_balance_records>rule_conditions_record.rdr_rng_from AND v_balance_records<rule_conditions_record.rdr_rng_to THEN
v_ssql_stmnt:='UPDATE t_scb_temp_objects
SET CHARGE='||rule_conditions_record.rfr_chrg_amt||' WHERE RULE_CONDITION='||rule_conditions_record.rdr_tmplt_id;
EXECUTE IMMEDIATE v_ssql_stmnt;
END IF;
END LOOP;
CLOSE c_rules_details;

Answer 1

That's what you've been told - you can't perform DML (in your case, UPDATE t_scb_temp_objects ...) within a function you're (somehow - you didn't show how) calling from a procedure. That might be - for example:
create or replace function f_test (par_deptno in number)
return number
is
...
begin
open c_rules_details;
loop
-- your current code goes here
execute immediate v_sql_stmnt;
end loop;
return 1;
end;
create or replace procedure p_test is
l_ename emp.ename%type;
begin
select e.ename
into l_ename
from emp e
where e.deptno = f_test(e.deptno); --> this will cause the error
end;
So, what to do? Perform UPDATE from within a procedure, not a function.
If it must be a function, make it an autonomous transaction (using PRAGMA), but that's something I wouldn't recommend. You'd rather figure something different out. Here's how, though:
SQL> create table test (col number);
Table created.
SQL> insert into test (col) values (100);
1 row created.
SQL> commit;
Commit complete.
First, a function that'll fail (just like yours):
SQL> create or replace function f_test return number is
2 begin
3 update test set col = 10;
4 commit;
5 return 1;
6 end;
7 /
Function created.
SQL> select f_test from dual;
select f_test from dual
*
ERROR at line 1:
ORA-14551: cannot perform a DML operation inside a query
ORA-06512: at "SCOTT.F_TEST", line 3
Now, the one which will succeed:
SQL> create or replace function f_test return number is
2 pragma autonomous_transaction; --> this
3 begin
4 update test set col = 10;
5 commit;
6 return 1;
7 end;
8 /
Function created.
SQL> select f_test from dual;
F_TEST
----------
1
SQL> select * from test;
COL
----------
10
SQL>
Once again: you probably don't want to do that.