Php Codeigniter模型函数从mysql获取数据

我正在使用下面的函数从mysql数据库获取数据

my mododel.php中的代码包装是：

 function get_all_devices($user_id = NULL) {
    if ($user_id) {
        $sql = "
            SELECT *
            FROM {$this->_db}
            WHERE user_id = " . $this->db->escape($user_id) . "

        ";

        $query = $this->db->query($sql);

        if ($query->num_rows()) {
            return $query->row_array();
        }
    }

    return FALSE;
}

数据库结构cols:

id、用户id、设备、值

但它只提取了最后一条记录。
如何获取数组中的所有记录。
使用
结果数组（）
而不是
行数组（）

它将返回所有记录<代码>行数组（）

只返回一条记录

使用

结果数组（）

而不是

行数组（）

---

它将返回所有记录

row\u array（）

只返回一条记录

好的，我将重构代码并在需要时进行修改：

function get_all_devices($user_id = NULL) {
        if ($user_id) {
            $this->db->where('user_id', $user_id);// you don't have to escape `$user_id` value, since `$this->db->where()` escapes it implicitly. 
            $query = $this->db->get($this->_db); //executes `select *` on table `$this->_db`, and returns.     
            //if you want to get only specific columns, use $this->db->select('col1, col2'), otherwise you don't need to specify it, since it implicitly selects everything.     
            if ($query->num_rows()) {
                return $query->result_array();//use result_array() to retrieve the whole result instead of row_array() which retrieves only one row;
            }
        }

        return FALSE;
    }

---

好的，我将重构代码并在需要时进行修改：

function get_all_devices($user_id = NULL) {
        if ($user_id) {
            $this->db->where('user_id', $user_id);// you don't have to escape `$user_id` value, since `$this->db->where()` escapes it implicitly. 
            $query = $this->db->get($this->_db); //executes `select *` on table `$this->_db`, and returns.     
            //if you want to get only specific columns, use $this->db->select('col1, col2'), otherwise you don't need to specify it, since it implicitly selects everything.     
            if ($query->num_rows()) {
                return $query->result_array();//use result_array() to retrieve the whole result instead of row_array() which retrieves only one row;
            }
        }

        return FALSE;
    }