I have a one-to-many relationship, which works perfectly when using the relationship as a property on a query, but when i try to use it as a method it always return empty.
User Model
public function reports()
{
return $this->hasMany('App\Report', Report::COL_USER_ID, self::COL_ID);
}
Report Model
public function user()
{
return $this->hasOne('App\User', User::COL_ID, self::COL_USER_ID);
}
This Works
$reports = User::find($id)->reports;
This Doesn't and i need something like this
$reports = User::find($id)->reports()->orderBy(Report::COL_CREATED_AT, self::ORDER_BY_DESC);
According to the eloquent doc, "since all relationships also serve as query builders, you can add further constraints", so that should totally be retrieving the proper data, am I missing something? Thanks in advance for any help
You need to use get method to get actual results, so you should use:
$reports = User::find($id)->reports()->orderBy(Report::COL_CREATED_AT, self::ORDER_BY_DESC)->get();
instead of only:
$reports = User::find($id)->reports()->orderBy(Report::COL_CREATED_AT, self::ORDER_BY_DESC);
In your case, you only created query and haven't get any results from database. That's why you don't get any results.
And the reason why:
$reports = User::find($id)->reports;
works is because it's shortcut for:
$reports = User::find($id)->reports()->get();
If you try to use:
$reports = User::find($id)->reports();
only you won't get any results either.
Related
I'm learning Laravel, so I'm quite new.
I have 2 Models: House and Translation.
My House Model:
use HasFactory;
protected $guarded = ['id'];
public function trans(){
return $this->hasMany(Translation::class);
}
}
My Translation Model:
function House(){
return $this->belongsTo(House::class);
}
}
When I do in the controller something like ($id=2 e.g) :
$house = House::find($id)::with('trans')->get();
I get a result with all houses (there are currently 2 in the DB).
When I just do the query "House::find($id)->get()" it works fine.
What part am I missing?
::with('trans') returns completely new query and forgets everything about your ::find($id)
you need to use load method.
$house = House::find($id);
$house->load('trans');
What happens is, House::find($id) is a method that returns the element by its primary key.
Then, the ::with('trans') gets the result, sees the House class and starts creating a new query builder for the Model.
Finally, the ->get() runs this new query and the end result is what is return for the $house value.
You have two options that will result to what you want to do.
First one is, to find the house entry and then load its relation
$house = House::find($id);
$house->load('trans');
The second option is this:
$house = House::where('id',$id)->with('trans')->first();
The second one is a query builder that results to the first element with id = $id,
and load its relation with translations.
You can check for more details in the laravel documentation. They have a very well-written documentation and the examples help a lot.
I started learning Laravel and I am trying to achieve the following:
Get data from database and display specific field.
Here is my code in the controller:
public function show()
{
$students = DB::select('select * from students', [1]);
return $students;
}
Here is my route code:
Route::get('', "StudentController#show");
That all works for me and I get the following displayed:
[{"id":1,"firstname":"StudentFirstName","lastname":"StudentLastName"}]
How can I get only the "lastname" field displayed?
Thanks in advance!
DB::select('select * from students')
is a raw query that returns an array of stdClass objects, meaning you have to loop through the array and access properties:
$students[0]->lastname
You can also use the query builder to return a collection of objects:
$collection = DB::table('students')->get();
$student = $collection->first();
$student->lastname;
Lastly, using the query builder, you can use pluck or value to get just the last name. If you only have one user, you can use value to just get the first value of a field:
DB::table('students')->where('id', 1)->value('lastname');
I strongly advise you to read the Database section of the Laravel docs.
$students[0]['lastname'] will return the last name field, the [0] will get the first student in the array.
I would recommend creating a model for Students, which would make your controller something like this:
$student = Students::first(); // to get first student
$student->lastname; // get last names
If you only want the one column returned, you can use pluck()
public function show()
{
$last_names= DB::table('students')->pluck('lastname');
return $last_names;
}
This will return an array of all the students' lastname values.
If you want just one, you can access it with $last_names[0]
As a side note, your show() method usually takes a parameter to identify which student you want to show. This would most likely be the student's id.
There are several ways you can accomplish this task. Firstly, I advise you to use the model of your table (probably Students, in your case).
Thus, for example,to view this in the controller itself, you can do something like this using dd helper:
$student = Students::find(1);
dd($student->lastname);
or, using pluck method
$students = Students::all()->pluck('lastname');
foreach($students as $lastName) {
echo $lastName;
}
or, using selects
$students = DB::table('students')->select('lastname');
dd($students);
Anyway, what I want to say is that there are several ways of doing this, you just need to clarify if you want to debug the controller, display on the blade...
I hope this helps, regards!
How do you return a collection of a grouped dataset in a ManytoMany relationship with this scenario?
Here is a sample of what dataset I want to return
So let's take the favorites as the genres and the highlighted date is the genres name, it's also a collection as well. I want to group it based on the genres name in that collection.
My model:
Video
```
public function genres() {
return $this->belongsToMany(Genre::class);
}
```
Genre
```
public function videos() {
return $this->belongsToMany(Video::class);
}
```
I tried the following already but can't seem to get it.
```
$videos = Video::with('genres')->all();
$collection = $videos->groupBy('genres.name');
```
I want to group the dataset by the genres name knowing the genre's relationship is also a collection of genres.
Try something like:
Video::with('genres')->get()->groupBy('genres.*.name');
Or:
$videos = Video::with('genres')->all();
$collection = $videos->groupBy('genres.*.name');
Note that above is code you posted, just after replacing "genres.name" with "genres.*.name".
Just noticed the post is old, this at least works on latest Laravel.
Collections and query builders share many similar functions such as where() groupBy() and so on. It's nice syntax sugar, but it really does obscure the underlying tech.
If you call $model->videos... like a property, that's a collection (query has executed).
If you call $model->videos()... like a method, that's a query builder.
So if you want to get the job done in sql, you can do something like...
$video_query_builder = Video::with('genere');
$video_query_builder->groupBy('genere_id');
$result = $video_query_builder->get();
You can chain it all together nice and neatly as was suggested in the comments... like this:
$result = Video::with('genere')
->groupBy('genere_id')
->get();
I'm having trouble with eager loading in laravel
I have these models:
class Page extends Eloquent {
public function translations() {
return $this->has_many('Pagestl', 'page_id');
}
}
and
class Pagestl extends Eloquent {
public static $table = 'pages_tl';
public function page() {
return $this->belongs_to('Page', 'id');
}
}
I want a specific page with its translation data of a specific language.
I retrieve the data like this:
$page_data = Page::with(array('translations' => function($query) {
$query->where('lang_id', '=', 'nl')->first();
}))->find($id);
De result is ok-ish. I get all the page data and the translation of 1 language, dutch (nl). But in order to get a field from the language data I have to this:
$page_data->translations[0]->attributes['content_or_whatever'];
..which i find ugly. I feel i should only have to do something like:
$page_data->translations->content;
..but that gives me an error (Trying to get property of non-object).
Am I missing something or is this just the way it is?
I don't find it necessary to do eager-loading here.
Both ways of doing it will result in 2 queries: select the Page with the given id and then find its first translation.
So, I would do:
$page = Page::find($id);
and then
$page_data = Pagestl::where_page_id_and_lang_id($page->id, 'nl')->first();
Then, assuming the content field exists in pages_tl table, we'll get it by doing:
echo $page_data->content;
Finally, your code looks alright; you don't have to have the second parameter when defining the relationships unless they are different from what Laravel expects.
I'll let you find where the problem is with your code (I couldn't figure out from the information given - could be something to do with strings.php)
Why is this not working?
Article::with('category')->find($ids)
I got a Array to String Conversion Exception.
But if i split the query into 2 parts like this:
$articles = Article::with('category')
and
$articles = $articles->find($ids)
I didn't get any exception and the result is right.
Just for the posterity... other way you can do this is:
Article::with('category')->whereIn('id', $ids)->get();
This should be faster because it's leaving the query to the database manager
Try:
Article::with('category')->get()->find($ids);
You need to get the articles first before you can call find() I believe.
Warning: This retrieves every single article from the database and loads them all into memory, and then selects just one from all that data and returns it. That is probably not how you would want to handle this problem.
This will give you the results based on an array of IDs in Laravel 4
Article::whereIn('id', $ids)->with('category')->get();
Create object and set his properties with relationships
for example, code in your Controller or Service
$article = new Article;
$article = $article->find($id);
$result->article = $article;
$result->article->category = $article->category;
return response()->json($result);
Code in your Model
public function category() {
return $this->hasOne('App\Category');
}