class User < ActiveRecord::Base
has_many :posts
end
class Question < ActiveRecord::Base
belongs_to :user
has_many :answers
end
class Answer < ActiveRecord::Base
belongs_to :question
end
如何使用Rails：
1.使用users返回所有questions？例如
@users_with_questions = User.joins(:question).where.not(question: { id: nil })
2.使用users返回所有answers？
答案 0 :(得分：1)
1.回答所有用户的问题？
@users_with_questions = User.includes(:question).where.not(:question => {id: nil})
2.使用答案返回所有用户？
@users_with_answers = User.includes(question: :answer).where.not(:answer => {id: nil})
答案 1 :(得分：0)
试试这个：
<?php
if (!defined('BASEPATH')) exit('No direct script access allowed');
error_reporting(1);
require_once(APPPATH . 'libraries/dropbox/vendor/autoload.php');
use \Dropbox as dbx;
class Knowledge extends CI_Controller
{
public $appInfoFile;
public $requestPath; **
public function __construct()
{
parent::__construct();
$this->load->library('session');
$this->load->helper('form');
$this->load->helper('url');
$this->load->database();
$this->load->library('form_validation');
//load the models
$this->load->model('knowledge_model');
//$this->load->helper('messages');
//$this->load->model('messages_model');
$this->load->model('messages_model', 'send_messages');
// custom library in codeigniter
$this->appInfoFile = APPPATH.'libraries/dropbox/app-info.json';
$redirect_uri ='https://www.domainname.com/knowledge/add/';
$requestPath = $this->init();
session_start();
validate_user();
}
public function index($msg = NULL)
{
$session_data = $this->session->all_userdata();
$data['msg'] = $msg;
if (isset($session_data["validated"]) && $session_data["validated"] == '1') {
$data['title'] = 'Knowledge Center';
$data['records'] = $this->knowledge_model->get_all_rec();
// echo "<pre>".print_r($data['records'],true)."</pre>";exit;
$this->load->view('includes/header', $data);
$this->load->view('includes/sidebar', $data);
$this->load->view('knowledge', $data);
$this->load->view('includes/footer');
} else {
redirect(base_url());
}
}
public function tag($msg = NULL)
{
$tagname = $this->uri->segment("3");
$tagnamehits = $this->uri->segment("4");
$session_data = $this->session->all_userdata();
$data['msg'] = $msg;
if (isset($session_data["validated"]) && $session_data["validated"] == '1') {
$data['title'] = 'Knowledge Center';
$data['update_rec'] = $this->knowledge_model->update_hits($tagnamehits);
$data['records'] = $this->knowledge_model->get_notifyrec_bytags($tagname);
//echo "<pre>".print_r($data['records'],true)."</pre>";exit;
$this->load->view('includes/header', $data);
$this->load->view('includes/sidebar', $data);
$this->load->view('knowledge', $data);
$this->load->view('includes/footer');
} else {
redirect(base_url());
}
}
public function add()
{
//validate form input
$this->form_validation->set_rules('subject', 'subject', 'required');
$this->data['message'] = (validation_errors() ? validation_errors() : $this->session->flashdata('message'));
$seralizedtags = serialize($this->input->post('tagsar'));
//echo "<pre>".print_r($seralizedArray,true)."</pre>";exit;
// drop box upload filess
if (isset($_FILES['attached_file']['name']) && !empty($_FILES['attached_file']['name'])) {
$file_name= $_FILES['attached_file']['name'];
$return_result=$this->upload_to_dropbox($file_name);
$rev=$return_result['rev'];
$mime_type=$return_result['mime_type'];
$path=$return_result['path'];
$size=$return_result['size'];
$revision=$return_result['revision'];
}
if ($this->form_validation->run() == true) {
$session_data = $this->session->all_userdata();
$user_id = $session_data["userid"];
$data = array(
'user_id' => $user_id,
'edit_by_userid' => $user_id,
'subject' => $this->input->post('subject'),
'tags' => $seralizedtags,
'description' => $this->input->post('description'),
'dropbox_rev'=>$rev,
'dropbox_mim_type'=>$mime_type,
'dropbox_path'=>$path,
'dropbox_filesize'=>$size,
'dropbox_revision'=>$revision,
);
$message=$this->input->post('subject');
//for slack call
if(isset($message)){
$message=$message;
$messageType = "Knowledge_center";
$this->send_messages->send_message_on_slack($messageType);
}
//echo "<pre>" . print_r($data, true) . "</pre>";
$insert_res = $this->knowledge_model->insert_rec($data);
if ($insert_res != "conf") {
if ($insert_res == "subject") {
$this->session->set_flashdata('message', "<p>Subject Name already exist.Please change Subject</p>");
} else {
$this->session->set_flashdata('message', "<p>Error in Insertion.</p>");
}
echo '<script>window.location.href = "' . base_url() . 'knowledge/add";</script>';
} else {
$this->session->set_flashdata('message', "<p>Record added successfully.</p>");
echo '<script>window.location.href = "' . base_url() . 'knowledge";</script>';
}
} else {
//set the flash data error message if there is one
$this->data['message'] = (validation_errors() ? validation_errors() : $this->session->flashdata('message'));
$this->data['subject'] = array(
'name' => 'subject',
'class' => 'form-control round-input',
'id' => 'subject',
'placeholder' => 'Subject',
'type' => 'text',
'autofocus' => 'true',
'data-required' => '1',
'value' => $this->form_validation->set_value('subject'),
);
$this->data['tagdata'] = array(
'name' => 'tagsar',
'class' => 'form-control tags tags-input',
'id' => 'tagsar',
'type' => 'text',
'autofocus' => 'true',
'data-type' => 'tags',
'value' => $this->form_validation->set_value('tagsar'),
);
$data['desc'] = $this->form_validation->set_value('description');
// $data['dropbox']=$this->dropbox->dp();
$msg = "";
$data['title'] = 'Knowledge Center';
$data['msg'] = $msg;
$this->load->view('includes/header', $data);
$this->load->view('includes/sidebar', $data);
$this->load->view('add_knowledge', $this->data);
$this->load->view('includes/footer');
}
}
public function view($id)
{
$update_rec = $this->knowledge_model->get_rec_byid($id);
$data['dropbox_detail']=array(
"dropbox_rev"=> $update_rec[0]->dropbox_rev,
"dropbox_mim_type"=> $update_rec[0]->dropbox_mim_type,
"dropbox_path"=> $update_rec[0]->dropbox_path,
"dropbox_filesize"=> $update_rec[0]->dropbox_filesize,
"dropbox_revision"=> $update_rec[0]->dropbox_revision,
);
$data['subject_data'] = $update_rec[0]->subject;
$data['tags_data'] = unserialize($update_rec[0]->tags);
$data['desc'] = $update_rec[0]->description;
$data['title'] = 'Knowledge Center';
$this->load->view('includes/header', $data);
$this->load->view('includes/sidebar', $data);
$this->load->view('view_knowledge', $this->data);
$this->load->view('includes/footer');
}
public function manage_notify()
{
$notifyid = $_POST["elid"];
$notifytext = $_POST["notifytext"];
$notify_rec = $this->knowledge_model->get_notifyrec_byid($notifytext);
$ret_res = "<ul>";
foreach ($notify_rec as $notify_record) {
$ret_res .= "<li>" . $notify_record->subject . "</li>";
}
$ret_res .= "</ul>";
echo $ret_res;
exit;
}
public function update($id)
{
//validate form input
$this->form_validation->set_rules('subject', 'subject', 'required');
$this->data['message'] = (validation_errors() ? validation_errors() : $this->session->flashdata('message'));
$update_rec = $this->knowledge_model->get_rec_byid($id);
//echo "<pre>".print_r($update_rec[0],true)."</pre>";exit;
$seralizedtags = serialize($this->input->post('tagsar'));
if ($this->form_validation->run() == true) {
$session_data = $this->session->all_userdata();
$user_id = $session_data["userid"];
$data = array(
'edit_by_userid' => $user_id,
'subject' => $this->input->post('subject'),
'tags' => $seralizedtags,
'description' => $this->input->post('description')
);
$recid = $this->input->post('recid');
// echo "<pre>".print_r($data,true)."</pre>";exit;
$update_res = $this->knowledge_model->update_rec($recid, $data);
if ($update_res > 0) {
$this->session->set_flashdata('message', "<p>Record Updated successfully.</p>");
echo '<script>window.location.href = "' . base_url() . 'knowledge";</script>';
} else {
$this->session->set_flashdata('message', "<p>Error in Updation.</p>");
echo '<script>window.location.href = "' . base_url() . 'knowledge/update/' . $recid . '";</script>';
}
} else {
//set the flash data error message if there is one
$this->data['message'] = (validation_errors() ? validation_errors() : $this->session->flashdata('message'));
if (isset($update_rec)) {
$this->data['recid'] = array(
'name' => 'recid',
'class' => 'form-control',
'id' => 'recid',
'type' => 'hidden',
'autofocus' => 'true',
'data-required' => '1',
'value' => $update_rec[0]->id,
);
$this->data['subject'] = array(
'name' => 'subject',
'class' => 'form-control round-input',
'id' => 'subject',
'placeholder' => 'Subject',
'type' => 'text',
'autofocus' => 'true',
'data-required' => '1',
'value' => $update_rec[0]->subject,
);
$tags_data = unserialize($update_rec[0]->tags);
$this->data['tagdata'] = array(
'name' => 'tagsar',
'class' => 'form-control tags tags-input',
'id' => 'tagsar',
'type' => 'text',
'autofocus' => 'true',
'data-type' => 'tags',
'value' => $tags_data,
);
$data['desc'] = $update_rec[0]->description;
} else {
$this->session->set_flashdata('message', "<p>Update Record not found.</p>");
echo '<script>window.location.href = "' . base_url() . 'knowledge";</script>';
}
$msg = "";
$data['title'] = 'Knowledge Center';
$data['msg'] = $msg;
$this->load->view('includes/header', $data);
$this->load->view('includes/sidebar', $data);
$this->load->view('edit_knowledge', $this->data);
$this->load->view('includes/footer');
}
}
public function download_dbx_file(){
$file_path = $_POST['dropbox_path'];
$mime_type = $_POST['dropbox_mim_type'];
$this->download_file($file_path,$mime_type);
}
public function del($id)
{
$this->knowledge_model->del_rec($id);
$this->session->set_flashdata('message', "<p>Record Deleted successfully.</p>");
redirect(base_url() . 'knowledge');
}
// for upload to dropbox //
function getAppConfig()
{
global $appInfoFile;
try {
$appInfo = dbx\AppInfo::loadFromJsonFile($this->appInfoFile);
}
catch (dbx\AppInfoLoadException $ex) {
throw new Exception("Unable to load \"$this->appInfoFile\": " . $ex->getMessage());
}
$clientIdentifier = "examples-web-file-browser";
$userLocale = null;
return array($appInfo, $clientIdentifier, $userLocale);
}
function getClient()
{
if (!isset($_SESSION['access-token'])) {
return false;
}
list($appInfo, $clientIdentifier, $userLocale) = $this->getAppConfig();
$accessToken = $_SESSION['access-token'];
return new dbx\Client($accessToken, $clientIdentifier, $userLocale,$appInfo->getHost());
}
function getWebAuth()
{
list($appInfo, $clientIdentifier, $userLocale) = $this->getAppConfig();
$redirectUri = getUrl("dropbox-auth-finish");
$csrfTokenStore = new dbx\ArrayEntryStore($_SESSION, 'dropbox-auth-csrf-token');
return new dbx\WebAuth($appInfo, $clientIdentifier, $redirectUri, $csrfTokenStore, $userLocale);
}
function respondWithError($code, $title, $body = "")
{
$proto = $_SERVER['SERVER_PROTOCOL'];
header("$proto $code $title", true, $code);
echo renderHtmlPage($title, $body);
}
function getUrl($relative_path)
{
if (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') {
$scheme = "https";
} else {
$scheme = "http";
}
$host = $_SERVER['HTTP_HOST'];
$path = getPath($relative_path);
return $scheme."://".$host.$path;
}
function getPath($relative_path)
{
if (PHP_SAPI === 'cli-server') {
return "/".$relative_path;
} else {
return $_SERVER["SCRIPT_NAME"]."/".$relative_path;
}
}
function init()
{
global $argv;
// If we were run as a command-line script, launch the PHP built-in web server.
if (PHP_SAPI === 'cli') {
launchBuiltInWebServer($argv);
assert(false);
}
if (PHP_SAPI === 'cli-server') {
// For when we're running under PHP's built-in web server, do the routing here.
return $_SERVER['SCRIPT_NAME'];
}
else {
// For when we're running under CGI or mod_php.
if (isset($_SERVER['PATH_INFO'])) {
return $_SERVER['PATH_INFO'];
} else {
return "/";
}
}
}
function launchBuiltInWebServer($argv)
{
// The built-in web server is only available in PHP 5.4+.
if (version_compare(PHP_VERSION, '5.4.0', '<')) {
fprintf(STDERR,
"Unable to run example. The version of PHP you used to run this script (".PHP_VERSION.")\n".
"doesn't have a built-in web server. You need PHP 5.4 or newer.\n".
"\n".
"You can still run this example if you have a web server that supports PHP 5.3.\n".
"Copy the Dropbox PHP SDK into your web server's document path and access it there.\n");
exit(2);
}
$php_file = $argv[0];
if (count($argv) === 1) {
$port = 5000;
} else if (count($argv) === 2) {
$port = intval($argv[1]);
} else {
fprintf(STDERR,
"Too many arguments.\n".
"Usage: php $argv[0] [server-port]\n");
exit(1);
}
$host = "localhost:$port";
$cmd = escapeshellarg(PHP_BINARY)." -S ".$host." ".escapeshellarg($php_file);
$descriptors = array(
0 => array("pipe", "r"), // Process' stdin. We'll just close this right away.
1 => STDOUT, // Relay process' stdout to ours.
2 => STDERR, // Relay process' stderr to ours.
);
$proc = proc_open($cmd, $descriptors, $pipes);
if ($proc === false) {
fprintf(STDERR,
"Unable to launch PHP's built-in web server. Used command:\n".
" $cmd\n");
exit(2);
}
fclose($pipes[0]); // Close the process' stdin.
$exitCode = proc_close($proc); // Wait for process to exit.
exit($exitCode);
}
public function upload_to_dropbox($filename){
if($filename != ''){
try {
$dbxClient = $this->getClient();
$remoteDir = "/";
if (isset($_POST['folder'])) $remoteDir = $_POST['folder'];
$remotePath = rtrim($remoteDir, "/")."/".$filename;
$fp = fopen($_FILES['attached_file']['tmp_name'], "rb");
$result = $dbxClient->uploadFile($remotePath, dbx\WriteMode::add(), $fp);
fclose($fp);
//$str = print_r($result, true);
return $result;
} catch (Exception $e) {
echo $e->getMessage();
exit;
}
}
else{
echo "File does not exists";
exit;
}
}
public function download_file($file_path,$file_mime_type){
if($file_path != '' && $file_mime_type != '' ) {
try {
$dbxClient = $this->getClient();
$path = $file_path;
$fd = tmpfile();
$metadata = $dbxClient->getFile($path, $fd);
header("Content-Type: $metadata[mime_type]");
fseek($fd, 0);
fpassthru($fd);
fclose($fd);
} catch (Exception $e) {
echo $e->getMessage();
exit;
}
}
else{
echo "Invalid Request";
exit;
}
}
}
所以你的例子：
children = Child.where( #something)
children_parents = Parent.joins(:children).where(children: {id: children} )
grandchildren = Grandchildren.where(#something)
grandchildren_parents = Parent.joins(children: :grandchildren).where(grandchildren: {id: grandchildren})
或
grandchildren_parents = Parent.joins(children: :grandchildren).where.not(grandchildren: {id: nil}).distinct
答案 2 :(得分：0)
在红宝石中：
@users_with_questions = User.all.select{|u| u.questions.present? }
@users_with_answers = User.all.select{|u| u.questions.present? && u.answers.present? }
class User < ActiveRecord::Base
has_many :questions
has_many :answers, :through => :questions
end
在一个SQL查询中（只有一种方法）：
@users_with_questions = User.find(Question.pluck(:user_id).uniq!)
questions = Question.find(Answer.pluck(:question_id).uniq!)
@users_with_answers = User.find(questions.pluck(:user_id).uniq!)