php - Returning Multiple Data with MySQL query -

there couple questions have regarding following code:

    // create new mysql connection, inserting host, username, passord, , database connecting     $conn = new mysqli('xxx', 'xxx', 'xxx',);     if(!$conn) {         die('connection failed: ' . $conn->error());     }      // create , execute mysql query     $sql = "select artist_name artists";      $result = $conn->query($sql);      // loop through returned data , output     while($row = $result->fetch_assoc()) {         printf(             "artist: %s<br />", $row['artist_name'], "<br />",             "profile: %s<br />", $row['artist_dob'], "<br />",             "date of birth: %s<br />", $row['artist_profile'], "<br />",             "password: %s<br />", $row['artist_password'], "<br />"         );     }      // free memory associated query     $result->close();      // close connection     $conn->close(); 

how can assign artist_dob, artist_profile, , artist_password , return browser?

what statement $conn->error() mean? don't understand -> sign does.

the printf() function return information screen. $conn->error() echo out database error if there 1 trying connect. -> means it's calling function object $conn object , has lots of functions , $conn->query() means run query function on $conn object.

you may want beginner php object-oriented tutorials: https://www.google.com/search?q=beginner+guide+to+php+oop