What is the function method for php to connect to mysql database?

The function that PHP uses to connect to the mysql database is mysqli_connect(). This function can open a new connection to the MySQL server. The syntax format is "mysqli_connect(hostname, username, password, database, [port], [ socket]);".

The operating environment of this tutorial: windows7 system, PHP7.1&&mysql8 version, DELL G3 computer

In PHP, you can use the mysqli_connect extension of mysqli () function to realize the connection to the MySQL database. The function syntax format is as follows:

mysqli_connect(host,username,password,dbname,port,socket);

Return value: Returns an object representing the connection to the MySQL server.

It should also be noted that the mysqli_connect() function is an alias of the mysqli::__construct() function, and all objects using mysqli() can also be used to connect to the database.

Example: The following is a simple code to connect to the database.

1) Process-oriented writing method

<?php
    $host     = &#39;localhost&#39;;
    $username = &#39;root&#39;;
    $password = &#39;root&#39;;
    $dbname   = &#39;test&#39;;
    $port     = &#39;3306&#39;;
    $link     = @mysqli_connect($host,$username,$password,$dbname,$port);   // 连接到数据库
    if($link){
        mysqli_set_charset($link,&#39;UTF-8&#39;);      // 设置数据库字符集
        $sql    = &#39;select * from user&#39;;         // SQL 语句
        $result = mysqli_query($link, $sql);    // 执行 SQL 语句，并返回结果
        $data   = mysqli_fetch_all($result);    // 从结果集中获取所有数据
        mysqli_close($link);
    }else{
        die(&#39;数据库连接失败！&#39;);
    }
    echo &#39;<pre class="brush:php;toolbar:false">&#39;;
    print_r($data);
?>

2) Object-oriented writing method

<?php
    $host     = &#39;localhost&#39;;
    $username = &#39;root&#39;;
    $password = &#39;root&#39;;
    $dbname   = &#39;test&#39;;
    $mysql    = new Mysqli($host, $username, $password, $dbname);
    if($mysql -> connect_errno){
        die(&#39;数据库连接失败：&#39;.$mysql->connect_errno);
    }else{
        $mysql -> set_charset(&#39;UTF-8&#39;); //  设置数据库字符集
        $sql = &#39;select * from user&#39;;         // SQL 语句
        $result = $mysql -> query($sql);
        $data = $result -> fetch_all();
        $mysql -> close();
    }
    echo &#39;<pre class="brush:php;toolbar:false">&#39;;
    print_r($data);
?>

The running results are as follows:

Array
(
    [0] => Array
        (
            [0] => 1
            [1] => 张三
        )
)

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