Need help solving Pl/sql issue - plsql

Question

I am trying to fill a database with random data, but the primary key needs to still be unique. I can fill the database with random data, but now I am trying to solve the primary key issue.
When running this code I get errors.
set SERVEROUTPUT on
create or replace
PROCEDURE fillDatabase(TableIn IN varchar2, Amount IN NUMBER) IS
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(*) into columnNR
from user_tab_columns where table_name=TableIn;
FOR counter IN 1..Amount
LOOP
sqlStatement := 'insert into '|| TableIn ||' values (';
FOR counter2 IN 1..columnNR
LOOP
SELECT cols.table_name, cols.column_name into prmtab, prmname
FROM all_constraints cons, all_cons_columns cols
WHERE cols.table_name = TableIn
AND cons.constraint_type = 'P'
AND cons.constraint_name = cols.constraint_name
AND cons.owner = cols.owner
ORDER BY cols.table_name, cols.position;
tempstr := 'select count(*) into temp from '|| prmtab;
dbms_output.put_line('test');
dbms_output.put_line(temp);
EXECUTE IMMEDIATE tempstr;
IF temp = 0
THEN
strq := 'SELECT max(' || prmname || ') into prmkey from '|| prmtab || ' order by '|| prmname;
dbms_output.put_line(strq);
EXECUTE IMMEDIATE strq;
END IF;
select dbms_random.value(0, 20) into intlol from dual;
select dbms_random.string('U', 20) into str from dual;
SELECT SYSDATE + dbms_random.value(0, SYSDATE - SYSDATE+1)
INTO l_ran_time
FROM dual;
Select DATA_TYPE INTO columnData
FROM user_tab_columns
WHERE table_name= TableIn
AND COLUMN_ID = counter2;
dbms_output.put_line(columnData);
CASE
WHEN columnData = 'VARCHAR2' THEN sqlStatement := sqlStatement ||''''|| str ||''', ';
WHEN columnData = 'NUMBER' THEN sqlStatement := sqlStatement || intlol ||', ';
WHEN columnData = 'TIMESTAMP(6)' THEN 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 you guys help me solve this?

Answer 1

use the pattern
str := 'select x from t where...';
execute immediate str into var;
instead of
str := 'select x into var from t where...';
execute immediate str;