DECLARE
	begin
		INSERT INTO T1 VALUES(3);
	end;

SQL> @path/first.sql
6  

DECLARE
	begin
		INSERT INTO T1 VALUES(3);
	end;
/

SQL> @path/first.sql

PL/SQL procedure successfully completed.

 select * from t2;

         X          Y          Z
---------- ---------- ----------
         1          2          3


INSERT INTO T2 VALUES(4,5,6);
/

SQL>  @path/first.sql

PL/SQL procedure successfully completed.


1 row created.


1 row created.

SQL> select * from t2;

         X          Y          Z
---------- ---------- ----------
         1          2          3
         4          5          6
         4          5          6

create or replace procedure checkSQL (p_sql varchar2) 
authid current_user
is 
   handle int := dbms_sql.open_cursor; 
begin 
   dbms_sql.parse (handle, p_sql, dbms_sql.native); 
   dbms_sql.close_cursor (handle); 
exception
  when others then 
    if dbms_sql.is_open(handle) then dbms_sql.close_cursor (handle); end if;
    raise;
end; 
/ 

SQL> exec checkSQL('select * from dual');

PL/SQL procedure successfully completed.

SQL> exec  checkSQL('select michel from dual');
BEGIN checkSQL('select michel from dual'); END;

*
ERROR at line 1:
ORA-00904: "MICHEL": invalid identifier
ORA-06512: at "MICHEL.CHECKSQL", line 11
ORA-06512: at line 1

SQL> exec  checkSQL(q'[update dba_users set username='FOO']')
BEGIN checkSQL(q'[update dba_users set username='FOO']'); END;

*
ERROR at line 1:
ORA-01031: insufficient privileges
ORA-06512: at "MICHEL.CHECKSQL", line 11
ORA-06512: at line 1