您好我一直在学习本书中的php PHP Solutions Dynamic Web Design Made Easy,并进入了必须使用mysqli api来处理数据库的部分。写完连接功能,并运行该脚本,我得到这个错误:在尝试读取数据时调用非对象的成员函数query()
这是我的代码:
function dbConnect($usertype , $connectionType = 'mysqli'){
$host = 'localhost';
$db = 'phpsols';
if($usertype == 'read'){
$user = 'psread';
$pwd = 'Aleczandru1989';
}elseif($usertype == 'write'){
$user = 'aleczandru';
$pwd = 'Aleczandru1989';
}else{
exit('Unrecognized type');
}
if($connectionType == 'mysqli'){
return new mysqli($host , $user , $pwd , $db) or die ('Cannot open database');
}else{
try{
return new PDO("mysql:host=$host;dbname=$db", $user, $pwd);
} catch (PDOException $e){
echo 'Cannot connect to database';
exit;
}
}
}
$conn = dbConnect('read');
$sql = 'SELECT * FROM images';
$result = $conn->query($sql) or die(mysqli_error()); //Line 5
$numRows = $result->num_rows;
在这种情况下,5号线是指$结果= $ conn->查询($ SQL )或死(mysqli_error());. 我在这里做错了什么?