In doctrine, is it possible to add a WHERE clause when fetching a property of an object that corresponds to a relationship?
In terms of concept, let's say I want to retrieve only the first 3 blog posts made in the last 5 days. My "blog" object has a "posts" property which is defined as a relationship.
Update...
As some people are having some difficulties understanding what I mean by a relationship:
class Blog extends Doctrine_Record {
...
public function setUp() {
$this->hasMany("Note as Posts", array(
"local" => "blog_name",
"foreign" => "post_id",
"refClass" => "BlogPost"
));
}
}
As you can see, this is an explicit relationship as supported by doctrine. When I query using it:
$instanceOfBlog->Posts...........
I'd like to know if I can add additional clauses at that time.
Not sure I follow you, but if it's what I think then in your BlogTable class:
public function getRecentPosts()
{
$qry = self::createQuery("b")
->innerJoin("b.Posts p")
->where("p.created_at > ?", date("Y-m-d H:i:s", strtotime("-5 days")))
->orderBy("p.created_at DESC")
->limit(3);
$results = $qry->execute();
}
Is that what you were after? This is based on the created_at field in the Posts object, and assumes a relationship is defined between the Blog and Posts tables.
I may have misunderstood your question entirely however :-)
Related
I have a model Asset with documents() { $this->hasMany(Document::class); } through a table data_asset_document. I extend Asset into multiple models, one of which is Equipment. In my seeder for Equipment, I attempt to create a Document bound to the Equipment record:
$asset = Equipment::create([...]);
$document = Document::create([
'name' => "$type Purchase Order",
'tracking_number' => app('incrementer')->current()
]);
$asset->documents()->save($document);
Eloquent produces this query:
update `data_document` set `equipment_id` = 1, `data_document`.`updated_at` = 2019-09-20 14:39:48 where `id` = 1
This is obviously incorrect, since data_document does not have an equipment_id column (Documents "belong to" several models besides Asset). How do I rewrite Asset::documents so that produces the correct mapping, even in its extensions? Or do I need to save my Document through a means other than Asset::documents?
Since your extended asset model is called Equipment, Laravel expects your foreign key to be called equipment_id. You will need to specify the actual foreign key of asset_id in your relationship.
https://laravel.com/docs/6.x/eloquent-relationships#one-to-many
hasMany
documents() {
$this->hasMany(Document::class, 'asset_id');
}
The problem is, I'm not convinced your relationship is really hasMany since you mention what looks like a pivot table data_asset_document as being involved. Many-to-many relationships, like mentioned in your title, would use the belongsToMany method.
https://laravel.com/docs/6.x/eloquent-relationships#many-to-many
https://laravel.com/docs/6.x/eloquent-relationships#has-many-through
I have various parent/child relationships, drilling down a few levels. What I want to know is if its possible to do something like this:
$student = Student::find(1);
$student->bursaries()->enrolments()->courses()->where('course','LIKE','%B%');
(With the end goal of selecting the course which is like '%B%'), or if I would have to instead use the DB Query builder with joins?
Models / Relationships
Student:
public function bursaries() {
return $this->hasMany('App\StudentBursary');
}
StudentBursary:
public function enrolments() {
return $this->hasMany('App\StudentBursaryEnrolment');
}
If what you want is to query all courses, from all enrollments, from all bursaries, from a students, then, unfortunately, you are one table too many from getting by with the Has Many Through relationship, because it supports only 3 tables.
Online, you'll find packages that you can import / or answers that you can follow to provide you more though of solutions, for example:
1) How to use Laravel's hasManyThrough across 4 tables
2) https://github.com/staudenmeir/eloquent-has-many-deep
Anyhow, bellow's something you can do to achieve that with Laravel alone:
// Eager loads bursaries, enrolments and courses, but, condition only courses.
$student = Student::with(['bursaries.enrolments.courses' => function($query) {
$query->where('course','LIKE','%B%');
}])->find(1);
$enrolments = collect();
foreach($student->bursaries as $bursary) {
$enrolments = $enrolments->merge($bursary->enrolments);
}
$courses = collect();
foreach ($enrolments as $enrolment) {
$courses = $courses->merge($enrolment->courses);
}
When you do $student->bursaries() instead of $student->bursaries, it returns a query builder instead of relationship map. So to go to enrolments() from bursaries() you need to do a bursaries()->get(). It should look like this.
$student->bursaries()->get()[0]->enrolments(), added the [0] because im using get(), you can use first() to avoid the [0]
$student->bursaries()->first()->enrolments()
But I'm not sure if it will suffice your requirement or not.
I am trying to query data from my database and pass the results to a view called events, the problem I have is that one of my queries will always return the same result because in the where condition the $events_id is the same always. Is there a better way to do the querying? A better logic?
This code is from my controller called EventController:
public function index()
{
$firm_id = DB::table('firms')->where('user_id', auth()->id())->value('id');
$events_id = DB::table('events')->where('firm_id', $firm_id)->value('id');
$events = DB::table('events')->where('firm_id', $firm_id)->get()->toArray();
$actual_events = DB::table('actual_events')->where('event_id', $events_id)->get()->toArray();
return view('events',['events' => $events,'actual_events' => $actual_events]);
}
Since the $events_id is the same every time, the $actual_events will only contain the first result.
The image I have uploaded shows the problem, my table's first three columns are fine. Starting from the fourth they contain repeated values:
As I guess, you need something like this:
$event_ids = DB::table('events')->where('firm_id', $firm_id)->pluck('id');
$actual_events = DB::table('actual_events')->whereIn('event_id', $event_ids)->get()->toArray();
or write about your problem in details and I will try to help you.
you just said that your tables have relation together.
in this case it's better you using the eloquent for that,
first you should type the relations in model of each table like this:
class User extends Authenticatable{
public function cities()
{
return $this->hasmany('App\City'); //you should type your relation
}
}
for relations you can use this link: laravel relationships
after that when you compact the $user variable to your view, you can use this syntax for getting the city value relation to this user: $user->cities;.
I'm using laravel and eloquent.
Actually I have problems filtering results from a table based on conditions on another table's attributes.
I have 3 tables:
venue
city
here are the relationships:
a city has many locations and a location belongs to a city.
a location belongs to a venue and a venue has one location.
I have a city_id attribute on locations table, which you may figured out from relationships.
The question is simple:
how can I get those venues which belong to a specific city?
the eloquent query I expect looks like this:
$venues=Venue::with('location')->where('location.city_id',$city->getKey());
Of course that's not gonna work, but seems like this is common task and there would be an eloquent command for it.
Thanks!
A couple of options:
$venues = Venue::whereIn('location_id', Location::whereCityId($city->id)->get->lists('id'))
->get();
Or possibly using whereHas:
$venues = Venue::whereHas('location', function($query) use ($city) {
$query->whereCityId($city->id);
})->get();
It is important to remember that each eloquent query returns a collection, and hence you can use "collection methods" on the result. So as said in other answers, you need a Eager Loading which you ask for the attribute you want to sort on from another table based on your relationship and then on the result, which is a collection, you either use "sortBy" or "sortByDesc" methods.
You can look at an example below:
class Post extends Model {
// imagine timpestamp table: id, publish, delete,
// timestampable_id, timestampble_type
public function timestamp()
{
return $this->morphOne(Timestamp::class, 'timestampable');
}
}
and then in the view side of the stuff:
$posts = App\Post::with('timestamp')->get(); // we make Eager Loading
$posts = $posts->sortByDesc('timestamp.publish');
return view('blog.index', compact('posts'));
I'm trying to return a Laravel collection object with relations where the resulting collection is based on a nested criteria (ie. a nested model's field value). So it would look something like this:
User -> Category -> Post -> Comments where comment.active == 1
In this case, I want the result to include all of a specific user's categories => posts => comments, where the comment is active. If it is active, it would be nested in the proper hierarchy (Category->Post->Comment). If the comment is not active, any related post and potentially category (if there are no other posts with active comments) should not show up in the collection at all.
I've tried eager loading through with(), load() and filter() with no luck. They will continue to load the relations with empty comment relations. Looking for guidance as to where to research: joins? filters? advanced wheres with nesting?
One attempt:
$user->categories->filter(function($category) {
return $category->isActive();
});
In my model I have all the relationships setup appropriately, and in addition to that I have setup isActive() as follows:
// Category model
public function isActive() {
$active = $this->posts->filter(function($post) {
return $post->isActive();
}
}
// Post model
public function isActive() {
return (boolean) $this->comments()->where('active', 1)->count();
}
This works as expected, but it also includes eagerly loaded nested relationships where comments have an active field of 0. Obviously I'm doing this the wrong way but would appreciate any direction.
Another attempt:
User::with(['categories.posts.comments' => function($q) {
$q->where('active', 1);
}])->find(1);
Unfortunately, this also loads relations (categories and posts) that have no active comments. Replacing the relations with 'categories.posts.isActive' does not work either.
Still confusing because you didn't provide enough code but you may try something like this to get all the users with nested categories.posts.comments without any condition:
$users = User::with('categories.posts.comments')->get();
But it'll give you every thing even when you don't have any comments but to add condition you may try something like this:
// It should return all user models with `categories - posts - active comments`
$users = User::with('categories.posts.activeComments')->get();
Post model:
public function activeComments() {
return $this->hasMany('Comment')->where('active', 1);
}
You may also add more filters using constraints like:
$users = User::with(array('categories.posts.activeComments' => function($query){
$query->whereNull('comments.deleted_at');
}))->get();
But I'm not sure about it, don't know enough about your relationships, so just gave you an idea.