plsql - Need help solving Pl/sql issue -

i trying fill database random data, primary key needs still unique. can fill database random data, trying solve primary key issue.

when running code errors.

set serveroutput on create or replace  procedure filldatabase(tablein in varchar2, amount in number)    columndata varchar2(50); columnnr   number(10); str  varchar2(500); sqlstatement varchar2(500); l_ran_time  timestamp; intlol    number(38); prmname    varchar2(50); prmtab    varchar2(50); prmkey    number(10); temp      number(30); tempstr   varchar2(50); lolnr     number(10); strq     varchar2(50);  begin    lolnr := 1;   select count(*) columnnr    user_tab_columns table_name=tablein;     counter in 1..amount   loop sqlstatement := 'insert '|| tablein ||' values (';  counter2 in 1..columnnr   loop      select cols.table_name, cols.column_name prmtab, prmname     all_constraints cons, all_cons_columns cols     cols.table_name = tablein     , cons.constraint_type = 'p'     , cons.constraint_name = cols.constraint_name     , cons.owner = cols.owner     order cols.table_name, cols.position;      tempstr := 'select count(*) temp '|| prmtab;     dbms_output.put_line('test');     dbms_output.put_line(temp);     execute immediate tempstr;     if temp = 0            strq := 'select max(' || prmname || ') prmkey '|| prmtab || ' order '|| prmname;       dbms_output.put_line(strq);       execute immediate strq;     end if;      select dbms_random.value(0, 20) intlol dual;     select dbms_random.string('u', 20) str dual;      select sysdate + dbms_random.value(0, sysdate - sysdate+1)      l_ran_time     dual;         select data_type columndata     user_tab_columns      table_name= tablein      , column_id = counter2;     dbms_output.put_line(columndata);     case         when columndata = 'varchar2' sqlstatement := sqlstatement ||''''|| str ||''', ';       when columndata = 'number'  sqlstatement := sqlstatement || intlol ||', ';       when columndata = 'timestamp(6)' sqlstatement := sqlstatement ||''''|| l_ran_time ||''', ';       else sqlstatement := sqlstatement || null || ', ';      end case;    end loop;     sqlstatement := substr(sqlstatement, 0, length(sqlstatement) -2);    sqlstatement := sqlstatement || ')';   dbms_output.put_line(sqlstatement);   execute immediate sqlstatement;   end loop;   end filldatabase; 

can guys me solve this?

use pattern

str := 'select x t where...'; execute immediate str var; 

instead of

str := 'select x var t where...'; execute immediate str;