Question

我正在构建一个浏览器游戏，以便学习html，css，php和MySQL。我写了下面的代码，允许玩家建造新的建筑物。桌子加载所有建筑物，一切正常，甚至插入数据库。但是，由于我是新手，我遇到的问题是应该放入DB的所有值都是空的。 $ _SESSION [user_id]有效。但不是数组中的值。所以我认为问题可能是我不知道如何正确地获得这些值。

所以，如果有人想在这里帮助我，我会非常感激和教育！：）

function buildings() {
    global $database;
    global $player;
    global $self_link;


    // Fetch buildings
    $result = $database->query("SELECT * FROM buildings");
    $buildings = array();
    while($building = $database->fetch($result)) {
        $buildings[$building['id']] = $building;
    }

    if(!empty($_POST['build'])) {
        $building_id = (int)$_POST['building_id'];
        $amount = $_POST['amount'];

        try {
            if($player->money < $buildings[$building_id]['cost']) {
                throw new Exception("You do not have enough money to build this!");
            }

            // Purchase technique
            $player->money -= $buildings[$building_id]['cost'] * $amount;
            $database->query("INSERT INTO player_buildings (owner_id, name, power_use, life, att_inf, att_veh, att_air, att_sea) 
                                    VALUES ('$_SESSION[user_id]', '$buildings[name]', '$power_use', '$life', '$att_inf', '$att_veh', '$att_air', '$att_sea')");
            $player->update();

            echo "Debugg: Buildings have been added.... I hope..";
        } catch (Exception $e) {
            echo $e->getMessage();
        }

    }
    // Display form 
    echo "<table style='width:900px;'>
        <tr>
            <th style='width:40% text-align:left;'>Name</th>
            <th style='width:50%;'>Description</th>
            <th style='width:5%;'>Price</th>
            <th style='width:5%;'>Power Usage</th>
            <th style='width:5%;'>&nbsp;</th>
        </tr>";
        foreach($buildings as $id => $building) {   
            echo "<tr>
                <td>{$building['name']}</td>
                <td>{$building['description']}</td>
                <td>{$building['cost']}</td>
                <td>{$building['power_use']}</td>
                <td>    
                    <form action='$self_link' method='POST'>
                        <input type='hidden' name='building_id' value='$id' />
                        <input style='width:40px' type='number' name='amount' value='amount' />
                        <input type='submit' name='build' value='Build' />
                    </form>
                </td>
            </tr>";
        }

    echo "</table>";
}

Answer 1

SELECT entryindex, exitindex, IF(entryA < exitA, '+10', '-10')
FROM (
  SELECT t1.`index` AS entryindex,
         (SELECT t2.`index` 
          FROM mytable AS t2
          WHERE t2.`index` > t1.`index` AND 
                ((t2.`A` >= t1.`A` + 10) OR (t2.`A` <= t1.`A` - 10))
          ORDER BY `index` LIMIT 1) AS exitindex,
          t1.`A` AS entryA,
         (SELECT t2.`A` 
          FROM mytable AS t2
          WHERE t2.`index` > t1.`index` AND 
                ((t2.`A` >= t1.`A` + 10) OR (t2.`A` <= t1.`A` - 10))
          ORDER BY `index` LIMIT 1) AS exitA        
  FROM mytable AS t1
  WHERE t1.`B` = 1) AS t 
ORDER BY entryindex

除非$buildings[$building['id']] = $building; ^^^^^^^^^^^^^^^ VALUES ('$_SESSION[user_id]', '$buildings[name]', '$power_[..snip..] ^^^^解析为文字$building['id']，否则您将访问数组中的未定义字段...

开启name和error_reporting进行确认 - 如果这是不正确的密钥，您将收到display_errors警告。

另外，您可能容易受到sql injection attacks的攻击。除非您在数据库库中启用了异常，否则您只需确定查询永远不会失败。

php数组值不会被导入数据库

1 个答案: