Question

我会切入追逐。此时我只能通过此类实现数据库连接。我无法进行查询。你能告诉我如何使这个工作和/或告诉我如何以更好的方式重新编码它。

<?php
class database{

public $dbHost = '';
public $dbUser = '';
public $dbPass = '';
public $dbName = '';

public $db;

public function __construct(){}

public function dbConnect(){
    $mysqli = new mysqli($this->dbHost, $this->dbUser, $this->dbPass, $this->dbName);

    /* check connection */
    if (mysqli_connect_errno()){
        printf("Connect failed: %s\n", mysqli_connect_error());
        exit();
    }else{
        echo 'connection made';
    }
    /* close connection */
    $mysqli->close();
}

public function query($sql){
    $query = $sql;
    self::preparedStatement($query);
}

public function preparedStatement(){
    if ($stmt = $mysqli->prepare($query)){

        /* execute statement */
        $stmt->execute();

        /* bind result variables */
        $stmt->bind_result($name, $code);

        /* fetch values */
        while ($stmt->fetch()) {
            printf ("%s (%s)\n", $name, $code);
        }

        /* close statement */
        $stmt->close();
    }
}

public function __destruct(){}

}
?>

Answer 1

这对我有用。我评论了我的变化。

<?php
class database{

public $dbHost = '';
public $dbUser = '';
public $dbPass = '';
public $dbName = '';

public $db;

public function __construct(){}

public function dbConnect(){
    ### not $mysqli
    $this->db = new mysqli($this->dbHost, $this->dbUser, $this->dbPass, $this->dbName);

    /* check connection */
    if (mysqli_connect_errno()){
        printf("Connect failed: %s\n", mysqli_connect_error());
        exit();
    }else{
        echo 'connection made';
    }
    /* close connection */
    ### $this->db->close(); // DO NOT close the connection here!
}

public function query($sql){
    $query = $sql;
    self::preparedStatement($query);
}

public function preparedStatement($query){ ### parameter $query added

    if ($stmt = $this->db->prepare($query)){ ### not $mysqli->prepare()

        /* execute statement */
        $stmt->execute();

        /* bind result variables */
        $stmt->bind_result($name, $code);

        /* fetch values */
        while ($stmt->fetch()) {
            printf ("%s (%s)\n", $name, $code);
        }

        /* close statement */
        $stmt->close();
    }
}

public function __destruct(){}

}


### Test code
/*
$db = new Database();
$db->dbHost = '127.0.0.1';
$db->dbUser = 'root';
$db->dbPass = 'root';
$db->dbName = 'test';
$db->dbConnect();
$db->query('SELECT * FROM test');
*/
?>

Answer 2

您已省略参数：

public function preparedStatement($query)

（这个方法实际上应该是静态的）

下次尝试在询问之前调试代码。即使是简单的echo语句也可以在这里完成。

编辑：，即使这样也行不通。我认为你误解了变量范围的概念。 $mysqli应该是该类的实例变量，因为如果您只是将其设置为preparedStatement()作为局部变量，它将不会保留到__construct()。

如何让这个mysqli数据库类工作？

2 个答案: