Question

我是PDP PDO的新手，这是我创建名为＆＃34; title＆＃34;

的数据库的代码

<?php
$servername = "localhost";
$username = "username";
$password = "password";

try {
    $conn = new PDO("mysql:host=$servername;dbname=myDB", $username, $password);
    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $sql = "CREATE DATABASE title";
    // use exec() because no results are returned
    $conn->exec($sql);
    echo "Database created successfully<br>";
    }
catch(PDOException $e)
    {
    echo $sql . "<br>" . $e->getMessage(); // THIS IS LINE NUMBER 17
    }

$conn = null;
?>

但这是我得到的错误，而我试图运行脚本

Notice: Undefined variable: sql in C:\xampp\htdocs\website\database\createdb.php on line 17

SQLSTATE[HY000] [1049] Unknown database 'myDB'

有什么问题？

Answer 1

您连接到此处未出现的数据库：

    func addAlert()
    {
    alert.addTextField(configurationHandler: { (textField) -> Void in
        textField.placeholder = "Enter Name"})
    //grab value from the text field and print when user clicks OK
    alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { (UIAlertAction) in
        let textField = self.alert.textFields![0] as UITextField
        print("Text Field: \(textField.text!)")
        self.addNote()
    }))
self.present(alert, animated: true, completion: nil)
}

删除dbname：

$conn = new PDO("mysql:host=$servername;dbname=myDB", $username, $password);

Answer 2

您在第7行遇到SQL错误，因为您正在尝试访问尚不存在的myDB并且正在抛出异常。

您收到未定义的变量错误，因为try语句中的代码在$sql被分配给任何内容之前失败。

尝试使用PHP PDO创建数据库时出错

2 个答案: