Experts, please help me see if I write this correctly

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$adminunix = "localhost";

$adminname = "root";

$adminpass = "root";

$admindb = "ckq";

//Connect to the database

$conn =new mysqli($adminunix,$adminname ,$adminpass,$admindb);

//Check the connection

if($conn->connect_error){

die("Connection failed". $conn->connect_error);

}

$sql = "SELECT * FROM lrx ";

$result = $conn-> ;query($sql);

if ($result->num_rows > 0) {

echo $result->num_rows;

while ($row=mysqli_fetch_assoc($result)){

echo '

';

      
var_dump($row);
      
}

      
}

      
$conn->close();
      
?>
      
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Question 1: How many methods are there in the mysqli class?
      
Question 2: $ Can row=mysqli_fetch_assoc($result) be written like this?
      
Question 3: ->What is the difference between num_rows and mysqli_num_rows()