我是一名 Java 开发人员，刚刚接到“一些快速简单的数据库操作”的任务——除了我对 PHP/MySQL 了解不多……我需要将一条记录插入数据库——但仅此而已如果电子邮件字段与数据库中已存在的字段不匹配。以下是我到目前为止为我的 PHP 代码收集的内容:
// Grab the values from the HTML form:
$newUserName = $_POST['newUserName'];
$newUserName = $mysqli->real_escape_string($newUserName);
$newUserEmail = $_POST['newUserEmail'];
$newUserEmail = $mysqli->real_escape_string($newUserEmail);
// Now search the DB to see if a record with this email already exists:
$mysqli->query("SELECT * FROM RegisteredUsersTable WHERE UserEmail = '$newUserEmail'");
现在我需要查看该搜索是否返回任何结果 - 意味着电子邮件已经存在 - 如果是，我需要提醒用户，否则我可以继续将新信息插入数据库，使用:
$mysqli->query("INSERT INTO RegisteredUsersTable (UserName, UserEmail) VALUES ('".$newUserName."', '".$newUserEmail."')");
有什么想法吗？
根据您的代码，这应该会为您指明正确的方向。也许有更好的方法来构建您的数据库，从而更好地利用它。
<?php
$mysqli = new mysqli("localhost", "iodine", "iodine","iodine");
// Grab the values from the HTML form:
/*
$newUserName = $_POST['newUserName'];
$newUserName = $mysqli->real_escape_string($newUserName);
$newUserEmail = $_POST['newUserEmail'];
$newUserEmail = $mysqli->real_escape_string($newUserEmail);
*/
$newUserName = "Test User";
$newUserEmail = "test4@example.com";
// Now search the DB to see if a record with this email already exists:
echo "SELECT * FROM RegisteredUsersTable WHERE UserEmail = '$newUserEmail'", "\n";
$result = $mysqli->query("SELECT * FROM RegisteredUsersTable WHERE UserEmail = '$newUserEmail'");
if (!$result) {
die($mysqli->error);
}
echo "num_rows = ".$result->num_rows."\n";
if ($result->num_rows > 0) {
echo "Duplicate email\n";
// do something to alert user about non-unique email
} else {
$result = $mysqli->query("INSERT IGNORE INTO RegisteredUsersTable (UserName, UserEmail) VALUES ('".$newUserName."', '".$newUserEmail."')");
if ($result === false) {echo "SQL error:".$mysqli->error;}
}
?>