php - MySQL 无法添加新记录

Question

基本上我可以使用它创建记录，但它不会自动更新我的 ID 列以允许新记录。我需要添加表达式来更新计数器吗？或者是否有一个按钮或开关可以使用 phpmyadmin 在提交时自动创建新的 id？

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "message";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $sql = "INSERT INTO adminmessages (UserName, Message, Score)
    VALUES ('SammyWest', 'Test1', '100')";
    // use exec() because no results are returned
    $conn->exec($sql);
    echo "New record created successfully";
    }
catch(PDOException $e)
    {
    echo $sql . "<br>" . $e->getMessage();
    }

$conn = null;
?>

表架构

    1   IDPrimaryIndex  int(255)            No  None        Change Change   Drop Drop   
Primary Primary
Unique Unique
Index Index
Spatial Spatial
Fulltext Fulltext
More
    2   UserName    varchar(255)            No  None        Change Change   Drop Drop   
Primary Primary
Unique Unique
Index Index
Spatial Spatial
Fulltext Fulltext
More
    3   Message varchar(255)            No  None        Change Change   Drop Drop   
Primary Primary
Unique Unique
Index Index
Spatial Spatial
Fulltext Fulltext
More
    4   Score   int(255)            No  None        Change Change   Drop Drop   
Primary Primary
Unique Unique
Index Index
Spatial Spatial
Fulltext Fulltext
More

Answer 1

您必须使用以下方法将 id 列定义为自动增量主键字段:

ALTER TABLE adminmessages CHANGE id id INT AUTO_INCREMENT PRIMARY KEY;