String sql;
            int show;
            int screen;
            String time;
            String date;
            for(show = 1 ; show <43 ; show++) {
                if (show%6 == 1 || show%6 == 2)
                    screen = 1;
                else if (show%6 == 3 || show%6 == 4)
                    screen = 2;
                else
                    screen = 3;

                if (show%2 == 1)
                    time = "19:00";
                else
                    time = "21:30";

                if (show <= 6)
                    date = "22-12-2014";
                else if (show > 6 && show <= 12)
                    date = "23-12-2014";
                else if (show > 12 && show <= 18)
                    date = "24-12-2014";
                else if (show > 18 && show <= 24)
                    date = "25-12-2014";
                else if (show > 24 && show <= 30)
                    date = "26-12-2014";
                else if (show > 30 && show <= 36)
                    date = "27-12-2014";
                else
                    date = "28-12-2014";

                sql = "INSERT INTO shows " +
                        "VALUES (" + show + ", " + screen + ", '" + time + "', '" + date + "')";
                stmt.executeUpdate(sql);
            }

Giver fejlen com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '1' for key 1
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:408)