在boolean上调用成员函数bind_param()

Question

我尝试将参数绑定到php中的sql(mysqli),但是有一个错误代码,如上所述.这是我写的代码:

$stmt = $conn->prepare("INSERT INTO assignments (Classes_has_Subjects_classesHasSubjectsId, assignmentName, gradeForAssignment,protectiveGrade) 
                                  VALUES (?, ?, ?, ?)");
if ($stmt = false)
{
    echo "false";
}
else{
    $stmt->bind_param("sss", $classesHasSubjectsId, $assignmentName, $gradeForAssignment,  $protectiveGrade);
    $stmt->execute();
}

这是错误信息:11

致命错误:在布尔值中调用成员函数bind_param()

怎么了？

Answer 1

<?php
$stmt = $conn->prepare("INSERT INTO assignments (Classes_has_Subjects_classesHasSubjectsId, assignmentName, gradeForAssignment,protectiveGrade) 
                                  VALUES (?, ?, ?, ?)");
    if (!$stmt) {
        echo "false";
    }
    else {
        $stmt->bind_param("ssss", $classesHasSubjectsId, $assignmentName, $gradeForAssignment,  $protectiveGrade);
        $stmt->execute();
    }

if ($stmt = false)意味着你要分配false给$stmt.替换为if (!$stmt).

您绑定了4个参数,但只提供了3种类型的值.假设你的所有值都是字符串,我s在bind_param函数中添加了一个.如果某些值是整数更换相应的s用i.如果有双打,请替换为d.

你确定表中第一个字段的名字assignments是Classes_has_Subjects_classesHasSubjectsId？