Query the links Database

时间:2012-06-04 作者:Rob Myrick

您好,我正在尝试从一个在同一页上显示数据数组的“示例”wp\\U list\\U表转换为一个从数据库中提取数据的“真实”表。我有代码设置,我只需要添加DB查询就可以了。

我只是不知道如何查询数据库并使其正确显示。有人愿意看看下面的代码并告诉我如何在wordpress中查询“links”数据库表吗?我认为下面的查询可以工作,但我认为它与我的“示例”表行和列不匹配。

$sql = "SELECT * FROM links"; 
$data = $wpdb->get_results($sql);  
在下面的代码中,向下滚动大约3/4($data = $this->example_data;), 如果这是一段工作代码,您将看到创建数据库查询的区域。

这是我的functions.php 文件

<?php

/* == NOTICE ===================================================================
 * Please do not alter this file. Instead: make a copy of the entire plugin, 
 * rename it, and work inside the copy. If you modify this plugin directly and 
 * an update is released, your changes will be lost!
 * ========================================================================== */



/*************************** LOAD THE BASE CLASS *******************************
 *******************************************************************************
 * The WP_List_Table class isn\'t automatically available to plugins, so we need
 * to check if it\'s available and load it if necessary.
 */
if(!class_exists(\'WP_List_Table\')){
require_once( ABSPATH . \'wp-admin/includes/class-wp-list-table.php\' );
}




/************************** CREATE A PACKAGE CLASS *****************************
 *******************************************************************************
 * Create a new list table package that extends the core WP_List_Table class.
* WP_List_Table contains most of the framework for generating the table, but we
* need to define and override some methods so that our data can be displayed
* exactly the way we need it to be.
 *   
* To display this example on a page, you will first need to instantiate the class,
* then call $yourInstance->prepare_items() to handle any data manipulation, then
* finally call $yourInstance->display() to render the table to the page.
* 
* Our theme for this list table is going to be movies.
*/
class TT_Example_List_Table extends WP_List_Table {

/** ************************************************************************
 * Normally we would be querying data from a database and manipulating that
 * for use in your list table. For this example, we\'re going to simplify it
 * slightly and create a pre-built array. Think of this as the data that might
 * be returned by $wpdb->query().
 * 
 * @var array 
 **************************************************************************/
var $example_data = array(
        array(
            \'ID\'        => 1,
            \'title\'     => \'300\',
            \'rating\'    => \'R\',
            \'director\'  => \'Zach Snyder\'
        ),
        array(
            \'ID\'        => 2,
            \'title\'     => \'Eyes Wide Shut\',
            \'rating\'    => \'R\',
            \'director\'  => \'Stanley Kubrick\'
        ),
        array(
            \'ID\'        => 3,
            \'title\'     => \'Moulin Rouge!\',
            \'rating\'    => \'PG-13\',
            \'director\'  => \'Baz Luhrman\'
        ),
        array(
            \'ID\'        => 4,
            \'title\'     => \'Snow White\',
            \'rating\'    => \'G\',
            \'director\'  => \'Walt Disney\'
        ),
        array(
            \'ID\'        => 5,
            \'title\'     => \'Super 8\',
            \'rating\'    => \'PG-13\',
            \'director\'  => \'JJ Abrams\'
        ),
        array(
            \'ID\'        => 6,
            \'title\'     => \'The Fountain\',
            \'rating\'    => \'PG-13\',
            \'director\'  => \'Darren Aronofsky\'
        ),
        array(
            \'ID\'        => 7,
            \'title\'     => \'Watchmen\',
            \'rating\'    => \'R\',
            \'director\'  => \'Zach Snyder\'
        )
    );

/** ************************************************************************
 * REQUIRED. Set up a constructor that references the parent constructor. We 
 * use the parent reference to set some default configs.
 ***************************************************************************/
function __construct(){
    global $status, $page;

    //Set parent defaults
    parent::__construct( array(
        \'singular\'  => \'movie\',     //singular name of the listed records
        \'plural\'    => \'movies\',    //plural name of the listed records
        \'ajax\'      => false        //does this table support ajax?
    ) );

}


/** ************************************************************************
 * Recommended. This method is called when the parent class can\'t find a method
 * specifically build for a given column. Generally, it\'s recommended to include
 * one method for each column you want to render, keeping your package class
 * neat and organized. For example, if the class needs to process a column
 * named \'title\', it would first see if a method named $this->column_title() 
 * exists - if it does, that method will be used. If it doesn\'t, this one will
 * be used. Generally, you should try to use custom column methods as much as 
 * possible. 
 * 
 * Since we have defined a column_title() method later on, this method doesn\'t
 * need to concern itself with any column with a name of \'title\'. Instead, it
 * needs to handle everything else.
 * 
 * For more detailed insight into how columns are handled, take a look at 
 * WP_List_Table::single_row_columns()
 * 
 * @param array $item A singular item (one full row\'s worth of data)
 * @param array $column_name The name/slug of the column to be processed
 * @return string Text or HTML to be placed inside the column <td>
 **************************************************************************/
function column_default($item, $column_name){
    switch($column_name){
        case \'rating\':
        case \'director\':
            return $item[$column_name];
        default:
            return print_r($item,true); //Show the whole array for troubleshooting purposes
    }
}


/** ************************************************************************
 * Recommended. This is a custom column method and is responsible for what
 * is rendered in any column with a name/slug of \'title\'. Every time the class
 * needs to render a column, it first looks for a method named 
 * column_{$column_title} - if it exists, that method is run. If it doesn\'t
 * exist, column_default() is called instead.
 * 
 * This example also illustrates how to implement rollover actions. Actions
 * should be an associative array formatted as \'slug\'=>\'link html\' - and you
 * will need to generate the URLs yourself. You could even ensure the links
 * 
 * 
 * @see WP_List_Table::::single_row_columns()
 * @param array $item A singular item (one full row\'s worth of data)
 * @return string Text to be placed inside the column <td> (movie title only)
 **************************************************************************/
function column_title($item){

    //Build row actions
    $actions = array(
        \'edit\'      => sprintf(\'<a href="?page=%s&action=%s&movie=%s">Edit</a>\',$_REQUEST[\'page\'],\'edit\',$item[\'ID\']),
        \'delete\'    => sprintf(\'<a href="?page=%s&action=%s&movie=%s">Delete</a>\',$_REQUEST[\'page\'],\'delete\',$item[\'ID\']),
    );

    //Return the title contents
   return sprintf(\'<a href="#"><b>%1$s</b></a> %3$s\',
        /*$1%s*/ $item[\'title\'],
        /*$2%s*/ $item[\'ID\'],
        /*$3%s*/ $this->row_actions($actions)
    );
}

/** ************************************************************************
 * REQUIRED if displaying checkboxes or using bulk actions! The \'cb\' column
 * is given special treatment when columns are processed. It ALWAYS needs to
 * have it\'s own method.
 * 
 * @see WP_List_Table::::single_row_columns()
 * @param array $item A singular item (one full row\'s worth of data)
 * @return string Text to be placed inside the column <td> (movie title only)
 **************************************************************************/
function column_cb($item){
    return sprintf(
        \'<input type="checkbox" name="%1$s[]" value="%2$s" />\',
        /*$1%s*/ $this->_args[\'singular\'],  //Let\'s simply repurpose the table\'s singular label ("movie")
        /*$2%s*/ $item[\'ID\']                //The value of the checkbox should be the record\'s id
    );
}


/** ************************************************************************
 * REQUIRED! This method dictates the table\'s columns and titles. This should
 * return an array where the key is the column slug (and class) and the value 
 * is the column\'s title text. If you need a checkbox for bulk actions, refer
 * to the $columns array below.
 * 
 * The \'cb\' column is treated differently than the rest. If including a checkbox
 * column in your table you must create a column_cb() method. If you don\'t need
 * bulk actions or checkboxes, simply leave the \'cb\' entry out of your array.
 * 
 * @see WP_List_Table::::single_row_columns()
 * @return array An associative array containing column information: \'slugs\'=>\'Visible Titles\'
 **************************************************************************/
function get_columns(){
    $columns = array(
        \'cb\'        => \'<input type="checkbox" />\', //Render a checkbox instead of text
        \'title\'     => \'Custom Widget Name\',
        \'rating\'    => \'Rating\',
        \'director\'  => \'Director\'
    );
    return $columns;
}

/** ************************************************************************
 * Optional. If you want one or more columns to be sortable (ASC/DESC toggle), 
 * you will need to register it here. This should return an array where the 
 * key is the column that needs to be sortable, and the value is db column to 
 * sort by. Often, the key and value will be the same, but this is not always
 * the case (as the value is a column name from the database, not the list table).
 * 
 * This method merely defines which columns should be sortable and makes them
 * clickable - it does not handle the actual sorting. You still need to detect
 * the ORDERBY and ORDER querystring variables within prepare_items() and sort
 * your data accordingly (usually by modifying your query).
 * 
 * @return array An associative array containing all the columns that should be sortable: \'slugs\'=>array(\'data_values\',bool)
 **************************************************************************/
function get_sortable_columns() {
    $sortable_columns = array(
        \'title\'     => array(\'title\',true),     //true means its already sorted
        \'rating\'    => array(\'rating\',false),
        \'director\'  => array(\'director\',false)
    );
    return $sortable_columns;
}


/** ************************************************************************
 * Optional. If you need to include bulk actions in your list table, this is
 * the place to define them. Bulk actions are an associative array in the format
 * \'slug\'=>\'Visible Title\'
 * 
 * If this method returns an empty value, no bulk action will be rendered. If
 * you specify any bulk actions, the bulk actions box will be rendered with
 * the table automatically on display().
 * 
 * Also note that list tables are not automatically wrapped in <form> elements,
 * so you will need to create those manually in order for bulk actions to function.
 * 
 * @return array An associative array containing all the bulk actions: \'slugs\'=>\'Visible Titles\'
 **************************************************************************/
function get_bulk_actions() {
    $actions = array(
        \'delete\'    => \'Delete\'
    );
    return $actions;
}


/** ************************************************************************
 * Optional. You can handle your bulk actions anywhere or anyhow you prefer.
 * For this example package, we will handle it in the class to keep things
 * clean and organized.
 * 
 * @see $this->prepare_items()
 **************************************************************************/
function process_bulk_action() {

    //Detect when a bulk action is being triggered...
    if( \'delete\'===$this->current_action() ) {
        wp_die(\'Items deleted (or they would be if we had items to delete)!\');
    }

}


/** ************************************************************************
 * REQUIRED! This is where you prepare your data for display. This method will
 * usually be used to query the database, sort and filter the data, and generally
 * get it ready to be displayed. At a minimum, we should set $this->items and
 * $this->set_pagination_args(), although the following properties and methods
 * are frequently interacted with here...
 * 
 * @uses $this->_column_headers
 * @uses $this->items
 * @uses $this->get_columns()
 * @uses $this->get_sortable_columns()
 * @uses $this->get_pagenum()
 * @uses $this->set_pagination_args()
 **************************************************************************/
function prepare_items() {

    /**
     * First, lets decide how many records per page to show
     */
    $per_page = 5;


    /**
     * REQUIRED. Now we need to define our column headers. This includes a complete
     * array of columns to be displayed (slugs & titles), a list of columns
     * to keep hidden, and a list of columns that are sortable. Each of these
     * can be defined in another method (as we\'ve done here) before being
     * used to build the value for our _column_headers property.
     */
    $columns = $this->get_columns();
    $hidden = array();
    $sortable = $this->get_sortable_columns();


    /**
     * REQUIRED. Finally, we build an array to be used by the class for column 
     * headers. The $this->_column_headers property takes an array which contains
     * 3 other arrays. One for all columns, one for hidden columns, and one
     * for sortable columns.
     */
    $this->_column_headers = array($columns, $hidden, $sortable);


    /**
     * Optional. You can handle your bulk actions however you see fit. In this
     * case, we\'ll handle them within our package just to keep things clean.
     */
    $this->process_bulk_action();


    /**
     * Instead of querying a database, we\'re going to fetch the example data
     * property we created for use in this plugin. This makes this example 
     * package slightly different than one you might build on your own. In 
     * this example, we\'ll be using array manipulation to sort and paginate 
     * our data. In a real-world implementation, you will probably want to 
     * use sort and pagination data to build a custom query instead, as you\'ll
     * be able to use your precisely-queried data immediately.
     */
   $data = $this->example_data;




    /**
     * This checks for sorting input and sorts the data in our array accordingly.
     * 
     * In a real-world situation involving a database, you would probably want 
     * to handle sorting by passing the \'orderby\' and \'order\' values directly 
     * to a custom query. The returned data will be pre-sorted, and this array
     * sorting technique would be unnecessary.
     */
    function usort_reorder($a,$b){
        $orderby = (!empty($_REQUEST[\'orderby\'])) ? $_REQUEST[\'orderby\'] : \'title\'; //If no sort, default to title
        $order = (!empty($_REQUEST[\'order\'])) ? $_REQUEST[\'order\'] : \'asc\'; //If no order, default to asc
        $result = strcmp($a[$orderby], $b[$orderby]); //Determine sort order
        return ($order===\'asc\') ? $result : -$result; //Send final sort direction to usort

    usort($data, \'usort_reorder\');

}














































    /**
     * REQUIRED for pagination. Let\'s figure out what page the user is currently 
     * looking at. We\'ll need this later, so you should always include it in 
     * your own package classes.
     */
    $current_page = $this->get_pagenum();

    /**
     * REQUIRED for pagination. Let\'s check how many items are in our data array. 
     * In real-world use, this would be the total number of items in your database, 
     * without filtering. We\'ll need this later, so you should always include it 
     * in your own package classes.
     */
    $total_items = count($data);


    /**
     * The WP_List_Table class does not handle pagination for us, so we need
     * to ensure that the data is trimmed to only the current page. We can use
     * array_slice() to 
     */
    $data = array_slice($data,(($current_page-1)*$per_page),$per_page);



    /**
     * REQUIRED. Now we can add our *sorted* data to the items property, where 
     * it can be used by the rest of the class.
     */
    $this->items = $data;


    /**
     * REQUIRED. We also have to register our pagination options & calculations.
     */
    $this->set_pagination_args( array(
        \'total_items\' => $total_items,                  //WE have to calculate the total number of items
        \'per_page\'    => $per_page,                     //WE have to determine how many items to show on a page
        \'total_pages\' => ceil($total_items/$per_page)   //WE have to calculate the total number of pages
    ) );
}

}





/** ************************ REGISTER THE TEST PAGE ****************************
 *******************************************************************************
 * Now we just need to define an admin page. For this example, we\'ll add a top-level
 * menu item to the bottom of the admin menus.
 */
function tt_add_menu_items(){
add_menu_page(\'Custom Widgets\', \'Custom Widgets\', \'activate_plugins\', \'tt_list_test\', \'tt_render_list_page\');
} add_action(\'admin_menu\', \'tt_add_menu_items\');


/***************************** RENDER TEST PAGE ********************************
 *******************************************************************************
 * This function renders the admin page and the example list table. Although it\'s
 * possible to call prepare_items() and display() from the constructor, there
 * are often times where you may need to include logic here between those steps,
 * so we\'ve instead called those methods explicitly. It keeps things flexible, and
 * it\'s the way the list tables are used in the WordPress core.
 */
function tt_render_list_page(){

//Create an instance of our package class...
$testListTable = new TT_Example_List_Table();
//Fetch, prepare, sort, and filter our data...
$testListTable->prepare_items();

?>
<div class="wrap" style="width:70%">

    <div id="icon-themes" class="icon32"><br/></div>
    <h2>Custom Widgets</h2>
    <?php

$active_tab = isset( $_GET[ \'tab\' ] ) ? $_GET[ \'tab\' ] : \'custom_widget_manager\';

?>


    <h2 class="nav-tab-wrapper">
       <a href="?page=tt_list_test&tab=custom_widget_manager" class="nav-tab <?php echo $active_tab == \'custom_widget_manager\' ? \'nav-tab-active\' : \'\'; ?>">Custom Widget Manager</a>
       <a href="?page=tt_list_test&tab=add_custom_widget" class="nav-tab <?php echo $active_tab == \'add_custom_widget\' ? \'nav-tab-active\' : \'\'; ?>">Add Custom Widget</a>
        </h2>

   <!-- Forms are NOT created automatically, so you need to wrap the table in one to use features like bulk actions -->
    <form id="movies-filter" method="get">
        <!-- For plugins, we also need to ensure that the form posts back to our current page -->
        <input type="hidden" name="page" value="<?php echo $_REQUEST[\'page\'] ?>" />
        <!-- Now we can render the completed list table -->

        <?php $testListTable->display(); ?>

    </form>

</div>
<?php
}

1 个回复
最合适的回答,由SO网友:Eugene Manuilov 整理而成

WordPress在安装时设置的表名称中添加前缀。因此,默认情况下wp_ 表名称的前缀。这意味着默认情况下,链接的表名为wp_links. 但您不应该关心标准表的名称,因为它们都作为的参数存在wpdb 类(读取Table 节),因此您的查询应按如下方式构建:

$sql = "SELECT * FROM " . $wpdb->links; 
$data = $wpdb->get_results($sql);

结束

相关推荐

插件的uninstall.php文件可以访问插件的对象吗?

我在codex上读到,为插件实现干净卸载功能的最佳方法是添加卸载。插件目录中的php文件。我想知道:我可以在卸载中使用插件的类实例数据吗。php文件?这是我卸载中的代码。php文件:if(!defined(\'WP_UNINSTALL_PLUGIN\')) exit; delete_option(\'my_plugin_options\'); $table_name = $wpdb->prefix . $this->dbName; $wpdb->query(\"D