Question

我有一个带有方法sql（）的对象Obj，它创建SQL查询来更新数据库。数据库中的表具有其ID字段的唯一名称。我的目标是能够在子对象中定义表名和ID字段名。

class Obj {

  public static function sql(){
    $attributes = ['something', 'else', 'whatever'];
    foreach($attributes as $key => $value){
      $attribute_pairs[] = "{$key}='{$value}'";
    }

   $sql = "UPDATE " . static::$table_name . " SET ";
   $sql .= join(", ", $attribute_pairs);
   $sql .= " WHERE " . static::$id_name . "='" . static::$id_name . "' ";

   return $sql;
 }
}

class ChildObj extends Obj{
  protected static $table_name="accounts";
  protected static $id_name = "account_id";
}

$test = new ChildObj;

echo $test::sql(); 
//returns UPDATE accounts SET 0='something', 1='else', 2='whatever' WHERE account_id='account_id'

上面代码的问题是我无法弄清楚如何引用ID字段的值。特别是这一行：

$sql .= " WHERE " . static::$id_name . "='" . static::$id_name . "' ";

返回：

account_id='account_id'

我需要它来返回'account_id'的值

account_id='#'

如何在对象中设置静态变量变量？

0 个答案: