Question

我正在寻找一种方法来从使用PDO的SELECT查询返回的列索引中获取字段名称。我正在寻找的是等同于

mysql_field_name(resource $result, int $field_offset)

PHP文档说上面的函数从PHP 5.5.0开始被弃用，他们为PDO建议的替代方案被认为是实验性的，它的行为可能会在没有通知的情况下发生变化。这听起来不像我在申请中想要的东西。

我也不想查询MySQL系统表来获取列，因为这样效率不高。

如果fetchAll（）函数的结果返回下面的结果数组，有没有办法可以通过指定列索引来检索列名的值（下面等于“NAME”）？

Array
(
[0] => Array
    (
        [NAME] => pear
        [0] => pear
        [COLOUR] => green
        [1] => green
    )

[1] => Array
    (
        [NAME] => watermelon
        [0] => watermelon
        [COLOUR] => pink
        [1] => pink
    )

)

Answer 1

我想您可以使用array_flip($array)来交换数组的键/值，然后就可以轻松获得“NAME”字段

此外，您可以使用fetch(PDO::FETCH_ASSOC)检索数据，这样您只会获得查询的关联名称

Answer 2

当我读到这个问题时，我觉得我是发布它的人，因为它正是我想要的，因为我想从使用pdo的查询中动态创建一个html表，我不想使用show tables或query架构，我想使用我的查询中的字段

hector给出的答案正是关键，我只是想我会分享/发布一个工作样本，我正在解析一个数组以获取我的表头，我正在创建和html表，其中包含查询的项目db：

$sqlselect = "SELECT name, last, othercol FROM persontable";

// I prepare and execute my query
$stmt = $conn->prepare($sqlselect);
$stmt->execute();

//get full recordset: header and records
$fullrs = $stmt->fetchAll(PDO::FETCH_ASSOC); 

//get the first row (column headers) but do not go to next record
$colheaders = current($fullrs)

out = ""; //variable that will hold my table

out .= <table>;

//get my columns headers in the table          
foreach($colheaders as $key=>$val) 
{
    $out .= '<th>'.$key.'</th>';
}

//get my records in the table
foreach($fullrs as $row) 
{
    $out .= "<tr>"; 
        $out .= '<td>'.$row['name'].'</td>';
        $out .= '<td>'.$row['last'].'</td>';
        $out .= '<td>'.$row['othercol'].'</td>';
    $out .= "<tr>";
}

out .= </table>;  

//spit my table out
echo $out;

希望这有助于某人

Answer 3

虽然不需要创建对象，但这对我有用。

<?php
namespace yourNameSpace;

// Extend PDO class for safe error handling
Class SafePDO extends \PDO {

    public static function exception_handler($exception) {
        // Output the exception details
        die("Uncaught exception: " . $exception->getMessage());
    }

    public function __construct($dsn, $username='', $password='', $driver_options=array()) {

        // Temporarily change the PHP exception handler while we . . .
        set_exception_handler(array(__CLASS__, 'exception_handler'));

        // . . . create a PDO object
        parent::__construct($dsn, $username, $password, $driver_options);

        // Change the exception handler back to whatever it was before
        restore_exception_handler();
    }

}

class TableRows extends \RecursiveIteratorIterator { 
    function __construct($it) { 
        parent::__construct($it, self::LEAVES_ONLY); 
    }

    function current() {
        return "<td>" . parent::current(). "</td>";
    }

    function beginChildren() { 
        echo "<tr>"; 
    } 

    function endChildren() { 
        echo "</tr>" . "\n";
    } 
} 


trait traitSQLExecution {

    private function generateTable(
        $sql,
        $servername = "default_value",
        $username = "default_value",
        $password = "default_value",
        $dbname = "default_value"
    ) {

        // Connect to the database with defined constants
        $pdo = new SafePDO("mysql: host=$servername;dbname=$dbname", $username, $password);

        $pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);

        try {               
            $stmt = $pdo->prepare($sql);
            $stmt->execute();

            // set the resulting array to associative
            $result = $stmt->setFetchMode(\PDO::FETCH_ASSOC); 

            $recordSet = $stmt->fetchAll();

            echo '<table id="myReport"><tr>';

            // Get table headers dynamically
            foreach($recordSet[0] as $k=>$v) {
                echo "<th>$k</th>";
            }

            echo '</tr>';

            foreach(new TableRows(new \RecursiveArrayIterator($recordSet)) as $k=>$v) { 
                echo $v;
            }
        }
        catch(PDOException $e) {
            echo 'Error: ' . $e->getMessage();
        }
        $pdo = null;
        $stmt = null;
        echo '</table>';
    }
}

class obj_report {
    // use section is used to include reusable pieces of code
    use traitSQLExecution;


    // Construct is called upon instantiation of an object
    function __construct($table){
        /****************************************************************************************
        * Do not include public variables as this is bad design.
        * Only public methods should be available to change the object in a predictable fashion.
        ****************************************************************************************/

        if ( $table !== "" ) {
            $this->generateTable($table);
        }
    }
}

$obj = new obj_report((string)htmlspecialchars($_POST['table']) ?: "");
$obj = NULL;

?>

PHP - 使用PDO从列索引获取字段名称

3 个答案: