與雄辯的Laravel建立hasMany關系

Question

我有兩個帶有這種模式的表：

mysql> show columns from table_1;
+-------------+------------------+------+-----+---------------------+-----------
| Field       | Type             | Null | Key | Default             | Extra
+-------------+------------------+------+-----+---------------------+-----------
| id          | int(10) unsigned | NO   | PRI | NULL                | auto_incre
| id_world    | int(11)          | NO   |     | NULL                |
| key         | varchar(255)     | NO   |     | NULL                |
| name        | varchar(255)     | NO   |     | NULL                |
| description | varchar(255)     | NO   |     | NULL                |
| level       | int(11)          | NO   |     | 0                   |
| created_at  | timestamp        | NO   |     | 0000-00-00 00:00:00 |
| updated_at  | timestamp        | NO   |     | 0000-00-00 00:00:00 |
+-------------+------------------+------+-----+---------------------+-----------
8 rows in set (0.00 sec)

和

mysql> show columns from table_2;
+--------------+------------------+------+-----+---------------------+----------
------+
| Field        | Type             | Null | Key | Default             | Extra
      |
+--------------+------------------+------+-----+---------------------+----------
| id           | int(10) unsigned | NO   | PRI | NULL                | auto_incr
| key          | varchar(255)     | NO   |     | NULL                |
| level        | int(11)          | NO   |     | NULL                |
| name         | varchar(255)     | NO   |     | NULL                |
| description  | varchar(255)     | NO   |     | NULL                |
| price        | int(11)          | NO   |     | NULL                |
| amount       | int(11)          | NO   |     | NULL                |
| created_at   | timestamp        | NO   |     | 0000-00-00 00:00:00 |
| updated_at   | timestamp        | NO   |     | 0000-00-00 00:00:00 |
+--------------+------------------+------+-----+---------------------+----------
30 rows in set (0.00 sec)

我想獲取所有字段“來自table_2，其中table_2.key = table_1.key AND table_2.level = 10”，這是在我的模型中使用hasMany選項的正確方法嗎？

我的普通查詢如下所示：

SELECT A.key AS p_key,
       A.name AS p_key,
       A.description AS p_desc,
       A.level AS p_level,
       B.key AS r_key,
       B.level AS r_level,
       B.name AS r_name,
       B.description AS r_desc 
FROM 
       table_1 AS A,
       table_2 AS B
WHERE 
       B.key = A.key AND
       B.level = '1'

Answer 1

要使用這些表建立hasMany關系，您需要首先創建兩個模型，例如：

class TableOne extends Eloquent {

    protected $table = 'table_1';

    public function tableTwoItems()
    {
        return $this->hasMany('TableTwo', 'table_2.key', 'table_1.key')
                    ->where('table_2.level', 1);
    }
}

class TableTwo extends Eloquent {

    protected $table = 'table_2';
}

一旦在app/models目錄中創建了這些模型，就可以使用以下代碼：

$result = TableOne::with('tableTwoItems')->get();

要選擇項目/字段，您可以使用如下所示的內容：

$result = TableOne::with(array('tableTwoItems' => function($query){
    $query->select('table_2.key as k2', 'table_2.name as name2', 'more...');
}))->select('table_1.key as k1', 'table_1.name as name1', 'more...')->get();

您可以像這樣訪問它們：

$result->first()->tableTwoItems->first();

或者您可以循環$result ，也可以使用嵌套循環循環相關項目。 例如：

foreach($result as $tableOneItem)

    echo $tableOneItem->name;

    foreach($tableOneItem->tableTwoItems as $tabletwoItem)

        echo $tabletwoItem->name;

    endforeach;

endforeach;

嘗試在兩個表的key使用不同的字段名稱，並使它們也唯一。 有關更多信息，請閱讀雄辯的關系文檔。