title: Oracle PL/SQL Error ORA-06512 and ORA-00911 giving me issues
body: <p>I have the following PL/SQL Procedure:</p>
  
  <pre><code>create or replace 
  PROCEDURE DboOpdracht2(
    table_name_in IN VARCHAR2,
    amount_rows_in IN NUMBER)
  IS
    insert_query VARCHAR2 (2000);
    --cursors voor tabel layout
    CURSOR table_cur IS
    SELECT * FROM User_tab_cols
    WHERE table_name = UPPER(table_name_in);
  
  BEGIN
    FOR COUNT IN 1 .. amount_rows_in
    LOOP
    BEGIN
      insert_query := 'INSERT INTO ';
      insert_query := insert_query || UPPER(table_name_in);
      insert_query := insert_query || ' VALUES(';
      --loop voor elke cursor om te vullen
      FOR col IN table_cur
      LOOP
        --dbms_output.put_line(col.data_type);
        CASE col.data_type
        WHEN 'NUMBER' THEN
        insert_query := insert_query || ' dbms_random.value(0, (power(10,'||col.data_precision||')-1)/power(10,'||col.data_scale||'))';
        WHEN 'VARCHAR2' THEN
        insert_query := insert_query || ' dbms_random.string(''A'',' || col.data_length || ')';
        WHEN 'TIMESTAMP(6)' THEN
        insert_query := insert_query || ' ' || current_timestamp;
        ELSE
        insert_query := insert_query || ' NULL ';
        END CASE;
        --add comma
        insert_query := insert_query || ' ,';
      END LOOP;
      insert_query := SUBSTR(insert_query,1,LENGTH(insert_query)-1);
      insert_query := insert_query || ' );';
      dbms_output.put_line(insert_query);
      EXECUTE IMMEDIATE insert_query;
      insert_query := '';
      --EXCEPTION
      --WHEN OTHERS THEN
        --dbms_output.put_line('Exception! Something went wrong.');
        --insert_query:='';
      END;
    END LOOP;
    COMMIT;   
  END;
  </code></pre>
  
  <p>Upon trying to run it with the IN values:</p>
  
  <pre><code>(AUTEUR , 10)
  </code></pre>
  
  <p>It gives me the following error:
  ORA-00911: invalid character
  ORA-06512: at "SYSTEM.DBOOPDRACHT2", line 38
  ORA-06512: at line 8</p>
  
  <p>On line 38 there is a print that shows me the INSERT statement i generated in the loop which is:</p>
  
  <pre><code>INSERT INTO AUTEUR VALUES( dbms_random.value(0, (power(10,10)-1)/power(10,0)) , dbms_random.string('A',64) , dbms_random.string('A',255) , dbms_random.string('A',255) , dbms_random.string('A',2048)  );
  </code></pre>
  
  <p>Dump part is, this INSERT as is, just works fine! ,however somehow there is an issue with this whole procedure whenever i add the line: <code>EXECUTE IMMEDIATE...</code></p>
  
  <p>Any idea why this causes a problem while the actual string is no issue at all if run on it's own?</p>
  
  <p>Thanks in advance,
  Smiley</p>