How to convert mysql to mysqli?

问题:

I tired to convert my mysql to mysqli but seems to be getting a lot of errors and warnings i got no problem connecting to the data base but the rest of the code seems wrong what am i doing wrong?

sql:

<?php
mysql_connect("localhost", "root", "");
mysql_select_db("searchengine");

$sql = mysql_query(sprintf(
    "SELECT * FROM searchengine WHERE pagecontent LIKE '%s' LIMIT 0,%d",
        '%'. mysql_real_escape_string($_GET['term']) .'%',
        $_GET['results']));

while($ser = mysql_fetch_array($sql)) {
    echo "<h2><a href='$ser[pageurl]'>$ser[pageurl]</a></h2>";
}

// don't forget to close connection
mysql_close();


?>

mysqli

<?php
mysqli_connect("localhost","root","","searchengine") or die("Error " . mysqli_error($link));

$result = mysqli_query(sprintf(
    "SELECT * FROM searchengine WHERE pagecontent LIKE '%s' LIMIT 0,%d",
        '%'. mysqli_real_escape_string($_GET['term']) .'%',
        $_GET['results']));

while($ser = mysqli_fetch_array($result)) {
    echo "<h2><a href='$ser[pageurl]'>$ser[pageurl]</a></h2>";
}

mysqli_close();


?>

回答1:

you can try it by creating a mysqli object like described here: http://www.php.net/manual/en/class.mysqli.php

or simply like this:

$db = new mysqli($hostname, $username, $password, $database);

and then query it like this:

$result = $db->query('SQL HERE');

in your case the code for mysqli would look like this

$db = new mysqli("localhost","root","","searchengine");

$result = $db->query(sprintf(
  "SELECT * FROM searchengine WHERE pagecontent LIKE '%s' LIMIT 0,%d",
  '%'. mysqli_real_escape_string($_GET['term']) .'%',
  $_GET['results'])
);

while($ser = mysqli_fetch_array($result)) {
    echo "<h2><a href='$ser[pageurl]'>$ser[pageurl]</a></h2>";
}

回答2:

Try using OOP style instead of procedural, it is much cleaner and more readable:

    $mysqli = new mysqli("localhost", "root", "", "searchengine");

    $result = mysqli->query(sprintf(
"SELECT * FROM searchengine WHERE pagecontent LIKE '%s' LIMIT 0,%d",
    '%'. mysqli_real_escape_string($_GET['term']) .'%',
    $_GET['results']));

May I also suggest you read some articles about how to use mysqli and preparted statements, instead of just hacking away and not reading the documentation. Using prepared statements removes the need for sprintf. Here are some useful links:

PHP Website - http://www.php.net/manual/en/book.mysqli.php

An article I found on google in about 5 seconds and looks quite good -http://mattbango.com/notebook/code/prepared-statements-in-php-and-mysqli/

回答3:

In mysql, we used mysql_real_escape_string because you couldn't prepare statement.

Now with mysqli, you have the ability to prepare statements which is the preferred way.

<?php
$mysqli = new mysqli("localhost", "root", "password", "searchengine");
if ($mysqli->connect_errno) {
    echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") ";
}

$query = "SELECT * FROM searchengine WHERE pagecontent LIKE ? LIMIT 0,?";
$stmt = $mysqli->prepare($query);

if (!$stmt) {
    echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
$term = '%'.$_GET['term'].'%';
$result = $_GET['results'];

$stmt->bind_param("si", $term, $result);

$stmt->execute();

while ($ser = $stmt->fetch_assoc()) {
    echo "<h2><a href='".$ser['pageurl']."'>".$ser['pageurl']."</a></h2>";
}


$mysqli->close();
?>