函数的变量是未定义的

时间:2010-07-31 20:00:08

标签: php mysql function

我将整个分页脚本放入函数中,以便我可以多次使用它。代码很长,但只有一部分我遇到了麻烦。

在我调用函数paginate($connection, "categories");后,我使用

$sql = "SELECT * FROM categories ORDER BY cat_name LIMIT $start, $limit";

etc..

我得到了这些错误。

  

注意:未定义的变量:start   注意:未定义的变量:限制你   您的SQL语法有错误;   检查对应的手册   您的MySQL服务器版本   在'第1行'附近使用正确的语法

它没有识别我在查询上面调用的函数中的变量。我从来没有把这么多代码放在函数中,所以我不确定我该做什么。我尝试返回那些未定义的变量(在函数中)但是没有用。我也试图避免使用全局变量 - 我听说它们已被弃用了。

以下是实际功能

function paginate($connection, $tableName) {

//Pagination
$targetpage = "http://localhost/website/all_categories.php";    
$limit = 4; //sets how many rows to display on each page

//count rows
$sql = "SELECT COUNT(*) as num FROM $tableName";
$total_pages = $connection->query($sql) or die(mysqli_error($connection)); 
$row = $total_pages->fetch_assoc();
$total_pages = $row['num'];

//if there's no page number, set it to the first page
$stages = 3;
$page = isset($_GET['page']) ? $_GET['page'] : 0;
$start = empty($page) ? $start = 0 : $start = ($page - 1) * $limit;

// Initial page num setup
    if ($page == 0){$page = 1;}
    $prev = $page - 1;  
    $next = $page + 1;                          
    $lastpage = ceil($total_pages/$limit);      
    $LastPagem1 = $lastpage - 1;                    


    $paginate = '';
    if($lastpage > 1)
    {   

        $paginate .= "<div class='paginate'>";
        // Previous
        if ($page > 1){
            $paginate.= "<a href='$targetpage?page=$prev'>previous</a>";
        }else{
            $paginate.= "<span class='disabled'>previous</span>";   }



        // Pages    
        if ($lastpage < 7 + ($stages * 2))  // Not enough pages to breaking it up
        {   
            for ($counter = 1; $counter <= $lastpage; $counter++)
            {
                if ($counter == $page){
                    $paginate.= "<span class='current'>$counter</span>";
                }else{
                    $paginate.= "<a href='$targetpage?page=$counter'>$counter</a>";}                    
            }
        }
        elseif($lastpage > 5 + ($stages * 2))   // Enough pages to hide a few?
        {
            // Beginning only hide later pages
            if($page < 1 + ($stages * 2))       
            {
                for ($counter = 1; $counter < 4 + ($stages * 2); $counter++)
                {
                    if ($counter == $page){
                        $paginate.= "<span class='current'>$counter</span>";
                    }else{
                        $paginate.= "<a href='$targetpage?page=$counter'>$counter</a>";}                    
                }
                $paginate.= "...";
                $paginate.= "<a href='$targetpage?page=$LastPagem1'>$LastPagem1</a>";
                $paginate.= "<a href='$targetpage?page=$lastpage'>$lastpage</a>";       
            }
            // Middle hide some front and some back
            elseif($lastpage - ($stages * 2) > $page && $page > ($stages * 2))
            {
                $paginate.= "<a href='$targetpage?page=1'>1</a>";
                $paginate.= "<a href='$targetpage?page=2'>2</a>";
                $paginate.= "...";
                for ($counter = $page - $stages; $counter <= $page + $stages; $counter++)
                {
                    if ($counter == $page){
                        $paginate.= "<span class='current'>$counter</span>";
                    }else{
                        $paginate.= "<a href='$targetpage?page=$counter'>$counter</a>";}                    
                }
                $paginate.= "...";
                $paginate.= "<a href='$targetpage?page=$LastPagem1'>$LastPagem1</a>";
                $paginate.= "<a href='$targetpage?page=$lastpage'>$lastpage</a>";       
            }
            // End only hide early pages
            else
            {
                $paginate.= "<a href='$targetpage?page=1'>1</a>";
                $paginate.= "<a href='$targetpage?page=2'>2</a>";
                $paginate.= "...";
                for ($counter = $lastpage - (2 + ($stages * 2)); $counter <= $lastpage; $counter++)
                {
                    if ($counter == $page){
                        $paginate.= "<span class='current'>$counter</span>";
                    }else{
                        $paginate.= "<a href='$targetpage?page=$counter'>$counter</a>";}                    
                }
            }
        }

                // Next
        if ($page < $counter - 1){ 
            $paginate.= "<a href='$targetpage?page=$next'>next</a>";
        }else{
            $paginate.= "<span class='disabled'>next</span>";
            }

        $paginate.= "</div>";       


}
 echo $total_pages.' Results';
 // pagination
 echo $paginate;


}//end function

3 个答案:

答案 0 :(得分:1)

(注意 - 这不一定是问题,但是......)

$start = empty($page) ? $start = 0 : $start = ($page - 1) * $limit;

应该是

$start = empty($page) ? 0 : ($page - 1) * $limit;

答案 1 :(得分:0)

编辑:您显然在功能中定义了$start。如果它在您的SQL语句之前定义,那么它显然是可访问的。但是,如果你没有传递它$start$end,我认为你的分页功能将非常有用。您还可以使用以下语法定义默认值:

function paginate($connection, $tableName, $start=0, $end="ALL") {

原始跟随

功能有自己的范围;你应该传递函数在它之外定义的变量:

function paginate($connection, $tableName, $start, $end) {

唯一的例外是超级全球$GLOBALS$_GET$_POST$_COOKIE$_REQUEST$_SESSION$_FILES$_ENV$_SERVER

您还可以通过超全局数组$GLOBALS访问任何函数外部定义的函数,或者在函数实现的开头添加global $var;。但是,除了(可以说)应用程序作用域配置指令之外,您不鼓励这样做。

答案 2 :(得分:0)

您在函数内部设置了$start$limit,但您没有返回这些变量。函数内部的变量有自己的本地scope,因此无法从函数外部访问。

您需要在功能之外需要return the variables。由于您需要多个变量,因此可以在关联数组中返回这些变量。例如,如果将其作为函数的最后一行放置:

return array( 'start' => $start, 'limit' => $limit );

...你可以这样调用这个函数:

$result = paginate($connection, "categories");

...并使用如下结果:

$sql = 'SELECT * FROM categories ORDER BY cat_name LIMIT ' .
    $result['start'] . ', ' . $result['limit'];