PHP PDO Select 查询返回双精度值

Question

对于我的家用温度传感器，我使用的是带有 php、sqlite、PDO 和 HTML 的树莓派。

我在 sqlite 中创建了一个表

使用

BEGIN;
CREATE TABLE waarden (datum TEXT, tijd TEXT, zone TEXT, lucht REAL, temperatuur REAL);
COMMIT;

我使用 DHT22 的 rpi 记录一切正常，所以我没有创建一个网页，使用以下 php.file 通过 AJAX 访问数据

<?php
function datumConversie($datum){    
    $delen = explode('/',$datum,3);
    $geconverteerd  = $delen[2].$delen[0].$delen[1];
    return $geconverteerd;
}
ini_set('display_errors', 'On');
error_reporting(E_ALL | E_STRICT);

$db = new PDO("sqlite:/home/pi/sensor.db");
$result_array = array();
$date = $_POST["datepicker"];
$waarde = datumConversie($date);
$tijd=""; 
$temperatuur="";
$query = "SELECT datum, tijd, zone,lucht, temperatuur FROM waarden WHERE datum = $waarde";
$result = $db->query($query);

foreach($result as $row)
{
    array_push($result_array, $row);
}
echo json_encode($result_array);
$db = null;
?>

问题是，当我查看浏览器响应时，值似乎返回了两次。一次使用其适当的字段名称，一次使用其列索引。（0 是基准，1 是 tijd 等）。见下文

{"datum":"20170601","0":"20170601","tijd":"00:01","1":"00:01","zone":"kelder","2":" kelder","lucht":"53.0","3":"53.0","temperatuur":"24.3","4":"24.3"}, {"datum":"20170601","0":" 20170601","tijd":"00:06","1":"00:06","zone":"kelder","2":"kelder","lucht":"53.1","3" :"53.1","temperatuur":"24.3","4":"24.3"}, {"datum":"20170601","0":"20170601","tijd":"00:11"," 1":"00:11","区域":"kelder","2":"kelder","lucht":"53.1","3":"53.1","temperatuur":"24.2","4":"24.2"},

我怎样才能避免这种情况。我已经尝试了几种最终可以工作的转换，但这只是修补了一些缺陷而没有解决原因？

有什么建议

Answer 1

像这样设置默认的获取模式

$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ); 

或者

$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC); 

在运行提取之前

$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
foreach($result as $row) {
    array_push($result_array, $row);
}

或者fetchAll()使用准备好的和参数化的语句替换为单行，以减轻SQL 注入攻击

$query = "SELECT datum, tijd, zone,lucht, temperatuur 
            FROM waarden 
            WHERE datum = :datum";
$result->prepare($query);

$result->execute([':datum'=>$waarde]);

$result_array = $result->fetchAll(PDO::FETCH_ASSOC);

fetchAll(PDO::FETCH_ASSOC) 控制如何返回结果的参数。