我一直在创建一个预订系统,并创建约会,但我的SQL语句不起作用。我一直试图找到解决办法,但没有成功。
下面列出的是我的php代码。我的第一条SQL语句运行良好,并返回正确的ClientID,但是,第二条SQL语句并没有将其全部插入数据库。我对result做了var_dumps,返回bool(false),对result也做了mysqli_error,返回null。我的错误消息在最后只显示echo'd消息,而不显示mysqli_error或错误号。
(注意:为了保护数据,更改/删除了一些值)
<?php
session_start();
if(! $_SESSION['Username']) {
header("location:Index.php");
}
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "";
$tablename = "appointmentinformation";
$tablenamed = "clientinformation";
$connection = mysqli_connect("$servername", "$username", "$password", "$dbname") or die("Could not connect to the database");
$clientusername = $_SESSION['Username'];
$sql = "SELECT ClientID FROM $tablenamed WHERE Username = '$clientusername' LIMIT 1";
$results = mysqli_query($connection, $sql);
if (! $results) {
echo ("Could not select the data : " . mysql_error());
} else {
$datarows = mysqli_fetch_row($results);
$clientid = $datarows[0];
}
$date = $_POST["Date"];
$month = $_POST["Month"];
$year = $_POST["Year"];
$time = $_POST["Time"];
$length = $_POST["Length"];
$date = stripslashes($date);
$month = stripslashes($month);
$year = stripslashes($year);
$time = stripslashes($time);
$length = stripslashes($length);
$date = mysqli_real_escape_string($date);
$month = mysqli_real_escape_string($month);
$year = mysqli_real_escape_string($year);
$time = mysqli_real_escape_string($time);
$length = mysqli_real_escape_string($length);
$query = "INSERT INTO appointmentinformation (ClientID, Length, Date, Month, Year, Time, Price) VALUES ('$clientid', '$length', '$date', '$month', '$year', '$time', '$price')";
$result = mysqli_query($connection, $query);
if ($result) {
header("Location:UserCP.php");
} else {
echo ("Could not insert data : " . mysqli_error($result) . " " . mysqli_errno());
}
?>
$query = "INSERT INTO appointmentinformation (ClientID, Length, Date, Month, Year, Time, Price) VALUES ('$clientid', '$length', '$date', '$month', '$year', '$time', '$price')";
$result = mysqli_query($connection, $query);
if ($result) {
header("Location:UserCP.php");
} else {
echo ("Could not insert data : " . mysqli_error($result) . " " . mysqli_errno());
}
从mysqli_query返回的结果为null。这会将代码发送到其他分支。然后,您对mysqli_error($result)进行了编码,它等于mysqli_error(null)。
我读过的文档中说,用一个到查询的"链接"初始化一个变量。你用做到了这一点
$connection = mysqli_connect("$servername", "$username", "$password", "$dbname") or die("Could not connect to the database");
现在,您需要将其编码为mysqli_error($connection)和mysqli_errno($connection)。
一个额外的建议。在mysqli_connect语句之后立即添加此代码。
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}