PHP lernen – Zwei Möglichkeiten, eine Verbindung zu MySQL herzustellen

Zeichnen Sie zwei Möglichkeiten auf, wie PHP eine Verbindung zu MySQL herstellen kann.

Verspotten Sie zuerst die Daten und führen Sie dann SQL aus.

<span>/*</span><span>创建数据库</span><span>*/</span>
<span>CREATE</span> <span>DATABASE</span> <span>IF</span> <span>NOT</span> <span>EXISTS</span><span> `test`;

</span><span>/*</span><span>选择数据库</span><span>*/</span>
<span>USE</span><span> `test`;

</span><span>/*</span><span>创建表</span><span>*/</span>
<span>CREATE</span> <span>TABLE</span> <span>IF</span> <span>NOT</span> <span>EXISTS</span> `<span>user</span><span>` (
    name </span><span>varchar</span>(<span>50</span><span>),
    age </span><span>int</span><span>
);

</span><span>/*</span><span>插入测试数据</span><span>*/</span>
<span>INSERT</span> <span>INTO</span> `<span>user</span>` (name, age) <span>VALUES</span>(<span>'</span><span>harry</span><span>'</span>, <span>20</span>), (<span>'</span><span>tony</span><span>'</span>, <span>23</span>), (<span>'</span><span>harry</span><span>'</span>, <span>24</span>);

Die erste besteht darin, die native Methode von PHP zu verwenden, um eine Verbindung zur Datenbank herzustellen. Der Code lautet wie folgt:

<?<span>php
</span><span>$host</span> = 'localhost'<span>;
</span><span>$database</span> = 'test'<span>;
</span><span>$username</span> = 'root'<span>;
</span><span>$password</span> = 'root'<span>;
</span><span>$selectName</span> = 'harry';<span>//</span><span>要查找的用户名，一般是用户输入的信息</span>

<span>$connection</span> = <span>mysql_connect</span>(<span>$host</span>, <span>$username</span>, <span>$password</span>);<span>//</span><span>连接到数据库</span>
<span>mysql_query</span>("set names 'utf8'");<span>//</span><span>编码转化</span>
<span>if</span> (!<span>$connection</span><span>) {
    </span><span>die</span>("could not connect to the database.\n" . <span>mysql_error</span>());<span>//</span><span>诊断连接错误</span>
<span>}
</span><span>$selectedDb</span> = <span>mysql_select_db</span>(<span>$database</span>);<span>//</span><span>选择数据库</span>
<span>if</span> (!<span>$selectedDb</span><span>) {
    </span><span>die</span>("could not to the database\n" . <span>mysql_error</span><span>());
}
</span><span>$selectName</span> = <span>mysql_real_escape_string</span>(<span>$selectName</span>);<span>//</span><span>防止SQL注入</span>
<span>$query</span> = "select * from user where name = '<span>$selectName</span>'";<span>//</span><span>构建查询语句</span>
<span>$result</span> = <span>mysql_query</span>(<span>$query</span>);<span>//</span><span>执行查询</span>
<span>if</span> (!<span>$result</span><span>) {
    </span><span>die</span>("could not to the database\n" . <span>mysql_error</span><span>());
}
</span><span>while</span> (<span>$row</span> = <span>mysql_fetch_row</span>(<span>$result</span><span>)) {
    </span><span>//</span><span>取出结果并显示</span>
    <span>$name</span> = <span>$row</span>[0<span>];
    </span><span>$age</span> = <span>$row</span>[1<span>];
    </span><span>echo</span> "Name: <span>$name</span> "<span>;
    </span><span>echo</span> "Age: <span>$age</span> "<span>;
    </span><span>echo</span> "\n"<span>;
}</span>

Die Betriebsstruktur ist wie folgt:

Name: harry Age: 20<span> 
Name</span>: tony Age: 23 

Die zweite Methode besteht darin, PDO zum Herstellen einer Verbindung zur Datenbank zu verwenden. Der Code lautet wie folgt:

<?<span>php
</span><span>$host</span> = 'localhost'<span>;
</span><span>$database</span> = 'test'<span>;
</span><span>$username</span> = 'root'<span>;
</span><span>$password</span> = 'root'<span>;
</span><span>$selectName</span> = 'harry';<span>//</span><span>要查找的用户名，一般是用户输入的信息</span>

<span>$pdo</span> = <span>new</span> PDO("mysql:host=<span>$host</span>;dbname=<span>$database</span>", <span>$username</span>, <span>$password</span>);<span>//</span><span>创建一个pdo对象</span>
<span>$pdo</span>-><span>exec</span>("set names 'utf8'"<span>);
</span><span>$sql</span> = "select * from user where name = ?"<span>;
</span><span>$stmt</span> = <span>$pdo</span>->prepare(<span>$sql</span><span>);
</span><span>$rs</span> = <span>$stmt</span>->execute(<span>array</span>(<span>$selectName</span><span>));

</span><span>if</span> (<span>$rs</span><span>) {
    </span><span>//</span><span> PDO::FETCH_ASSOC 关联数组形式
    // PDO::FETCH_NUM 数字索引数组形式</span>
    <span>while</span> (<span>$row</span> = <span>$stmt</span>->fetch(PDO::<span>FETCH_ASSOC)) {
        </span><span>$name</span> = <span>$row</span>['name'<span>];
        </span><span>$age</span> = <span>$row</span>['age'<span>];
        </span><span>echo</span> "Name: <span>$name</span> "<span>;
        </span><span>echo</span> "Age: <span>$age</span> "<span>;
        </span><span>echo</span> "\n"<span>;
    }
}

</span><span>$pdo</span> = <span>null</span>;<span>//</span><span>关闭连接</span>

Das Ergebnis ist das gleiche wie beim ersten.

Das Obige stellt das Erlernen von PHP vor – zwei Möglichkeiten, eine Verbindung zu MySQL herzustellen, einschließlich der relevanten Inhalte. Ich hoffe, es wird für Freunde hilfreich sein, die sich für PHP-Tutorials interessieren.