php – $_POST可以区分具有相同名称的两个元素吗？

该示例是一个非常简单的添加记录/删除具有多个输入的书籍记录.这是代码：

if (isset($_POST['delete']) && isset($_POST['isbn']))
{
    $isbn  = get_post('isbn');
    $query = "DELETE FROM classics WHERE isbn='$isbn'";

    if (!mysql_query($query,$db_server))   
    echo "DELETE failed: $query<br />" .
    mysql_error() . "<br /><br />";
}

if (isset($_POST['author']) &&
    isset($_POST['title']) &&
    isset($_POST['category']) &&
    isset($_POST['year']) &&
    isset($_POST['isbn']))
{
    $author   = get_post('author');
    $title    = get_post('title');
    $category = get_post('category');
    $year     = get_post('year');
    $isbn     = get_post('isbn');

    $query = "INSERT INTO classics VALUES" .
        "('$author','$title','$category','$year','$isbn')";

    if (!mysql_query($query,$db_server))
        echo "INSERT failed: $query<br />" .
        mysql_error() . "<br /><br />";
}

echo <<<_END
<form action="sqltest.php" method="post"><pre>
    Author <input type="text" name="author" />
    Title <input type="text" name="title" />
    Category <input type="text" name="category" />
    Year <input type="text" name="year" />
    ISBN <input type="text" name="isbn" />
    <input type="submit" value="ADD RECORD" />
    </pre></form>
_END;

$query = "SELECT * FROM classics";
$result = mysql_query($query);

if (!$result) die ("Database access failed: " . mysql_error());
$rows = mysql_num_rows($result);

for ($j = 0 ; $j < $rows ; ++$j)
{
    $row = mysql_fetch_row($result);
    echo <<<_END
<pre>
  Author $row[0]
   Title $row[1]
Category $row[2]
    Year $row[3]
    ISBN $row[4]
</pre>
<form action="sqltest.php" method="post">
<input type="hidden" name="delete" value="yes" />
<input type="hidden" name="isbn" value="$row[4]" />
<input type="submit" value="DELETE RECORD" /></form>
_END;
}

mysql_close($db_server);

function get_post($var)
{
    return mysql_real_escape_string($_POST[$var]);
}
?>

当您使用if(isset($_ POST [‘delete’])&& isset($_ POST [‘isbn’]))引用$_POST中的元素时,其中delete和isbn被多次用作名称,$_POST知道要引用哪个元素删除？我假设由于您一次只能删除一条记录,因此数组中的元素将自动指向已设置的记录.但是,isset的第二个条件($_ POST [‘isbn’])如何知道要检查哪个“isbn”元素？和&&让$_POST [‘isbn’]“继承”正确的行？

谢谢您的帮助！并且对任何可能滥用词汇表示道歉.仍然习惯于一切.