I want to count the number of posts belongs to a tag. Should I use method or dynamic property?
<?php
class Tag extends Eloquent {
public function posts()
{
return $this->belongsToMany('Post');
}
public function postsCount()
{
return count($this->posts);
}
public function getPostsCountAttribute()
{
return count($this->posts);
}
}
So in template should I use dynamic property:
{{ $tag->postCount }}
or method:
{{ $tag->postCount() }}
Excerpt from the documentation of Laravel 4 regarding Eloquent's Dynamic Properties (accessor) in relationships (bold are mine):
Eloquent allows you to access your relations via dynamic properties. Eloquent will automatically load the relationship for you, and is even smart enough to know whether to call the get (for one-to-many relationships) or first (for one-to-one relationships) method. It will then be accessible via a dynamic property by the same name as the relation.
That said, using the method defined for the database relationship or the dynamic property (accessor) will behave differently.
If you issue the post count using the method as follows:
$count = $tag->posts()->count();
That will generate the proper SQL with the COUNT aggregate function.
In the other hand, if you issue the post count using the dynamic property (accessor) as follows:
$count = count($tag->posts);
That will fetch all the posts, convert them to an array of objects, then counting the number of element of the array.
In your case, the choice should depend of the usage of the posts related to a tag. If you just want to count, then use the method and the aggregate function. But, if apart from counting you will be doing something else with those posts, then use the dynamic property (accessor).
Related
I trying to learn laravel and to do some tests/demo apps. I've struggling now with laravel/eloquent tables relations. And I need advice.
I have 3 models [Application, Term, AppState] and their tables applications[id, terms_id, appStates_id, and other cols ], terms[id, startDate, endDate, ...], app_states[id, caption]
Application.php
public function term()
{
return $this->belongsTo('App\Term');
}
public function appState()
{
return $this->belongsTo('App\AppState');
}
in Term.php and AppState.php i have:
public function applications()
{
return $this->hasMany('App\Application');
}
How I can get let's say "caption"/"startDay"+"endDate" in blade for each application? I can get their ids $app->terms_id/$app->appStates_id in foreach loop, but i want get caption value from app_states table.
Has to be this relations also specified in migrations? In some tuts is mentioned, that is not needed in case i want to handle it only in laravel.
Thanks for advice
You can access a model's relationship values by calling the relationship method like a property.
$application = Application::find(1);
$application->term->startDate;
$application->term->endDate;
$application->appState->caption;
Also your relationship with AppState is wrong, since your foreign key doesn't follow a snake_case typing, you'll need to provide the appropriate key for it
public function appState()
{
return $this->belongsTo('App\AppState', 'appStates_id');
}
You might also want to check terms_id as well since the model name (Term) is singular but the foreign key is plural.
Has to be this relations also specified in migrations? In some tuts is mentioned, that is not needed in case i want to handle it only in laravel.
Well, yes, you don't need to if Laravel will only be the one accessing that database. But if any cases in the near future you decide to migrate to a different framework or use the same database in another application, it's better to include these relationships in the migration. Also a database administrator would probably cringe if you don't.
So provided your relationships are correctly setup, you can access them anywhere you have an instance of that model.
So for example, lets say you have passed a collection of applications to your view ($apps):
#foreach($apps as $app)
{{ $app->term->startDate }}
{{ $app->term->endDate }}
{{ $app->appState->caption }}
#endforeach
Important Note: We are accessing the Eloquent relationship using ->appState rather than ->appState(). The later is actually accessing a Query Builder instance and has some more advanced use cases
I am currently working on a desktop management application with laravel 5.6. According to the management rule a patient can have one or more consultations according to given dates. When I display the list of consultations, I have the same name that repeats, the name that repeats corresponds to the patient who had several consultations, my question of how to avoid this. What I want is the name, and all the dates for these consultations.
class Consultation extends Model
{
public function patient()
{
return $this->belongsTo('App\Models\Patient');
}
}
class Patient extends Model
{
public function consultations()
{
return $this->hasMany('App\Models\Consultation');
}
}
Here is the query :
$consultations = Consultation::all();
The simplest (but not the prettiest) way to do this is to simply find all patients with consultations. Put those patients in an array, and then in your blade you would loop through these patients and show the consultations individually.
Controller Code:
$active_patients = [];
foreach(Patient::all() as $patient) {
if($patient->consultations->count()>0)
array_push($active_patients,$patient);
}
Pass $active_patients to your view, then loop over it as shown below. Obviously, I don't know all of the attribute names for your Patient or Consultation models and you will need to fix html markup as required, but you can get the picture:
#foreach($active_patients as $patient)
<p>{{$patient->name}}:</p>
#foreach($patient->consultations as $consultation)
<p>{{$consultation->date}}</p>
#endforeach
#endforeach
Disclaimer: This is not the most robust way to do this. It's simply the most straightforward approach. The best way to do this is to use scoped queries combined with appended attributes. For instance, you would make a scope on the Patients model for all patients that have a consultation by using the 'whereHas' eloquent query method to find patients that have consultations scheduled. Then you could just reference them directly as ActivePatient rather than having to build an array each time you reference them. You could also append an attribute to the Consultations model that does the same thing and grabs each consultation for the specific users and makes a nested model collection, but that's much more involved. I'd be happy to share that method with you if you want, but the above code would at least provide you with a working method to achieve what you requested.
I have been trying to get my head around these polymorphic relationships all day. I might be over complicating/thinking it but. Can Laravel handle inverse polymorphic relationships? I have a registration flow that can have two types of field Models- normal field and customField.
When I loop through all the fields available it could pull the attributes from either NormalField or CustomField.
<?php
foreach($registrationFlow->fields->get() as $field)
{
echo $field->name; // could be custom field or could be normal field
}
?>
My difficulty is that, the example given in the docs works if you want to assign a photo to either staff or orders, but i want to assign either a customField or a normalField to a registrationFlow
*Edit
If you follow the example for the polymorphic many to many relationship, The tag class contains posts and videos- while i would want just a simple fields() method that relates to customField or normalField dependent on the type
First of all, you should take a look at the updated docs for Laravel 5.1: https://laravel.com/docs/5.1/eloquent-relationships#polymorphic-relations.
I think the difficulty with the example they provide is that the relationship between Photo and Staff/Product are "has-a" relationships, whereas you are trying to model an "is-a" relationship. However, you can model "is-a" essentially the same way. Take a look at this article: http://richardbagshaw.co.uk/laravel-user-types-and-polymorphic-relationships/.
Basically, the strategy is to define a generic model (and a generic table), perhaps in your case Field, that relates to your RegistrationFlow. You then have two subtype models, NormalField and CustomField, that have one-to-one relationships with Field. (there's your "is-a"). Thus, RegistrationFlow is indirectly related to your field subtypes.
Polymorphism comes in when you want to access the specific subtypes:
class Field extends Model {
public function fieldable()
{
return $this->morphTo();
}
}
Your base field table should have fieldable_id and fieldable_type columns defined (see the Eloquent docs).
You can then add methods to NormalField and CustomField that let you access the base model (your "inverse relationship"):
class NormalField {
public function field()
{
return $this->morphOne('Field', 'fieldable');
}
}
class CustomField {
public function field()
{
return $this->morphOne('Field', 'fieldable');
}
}
Usage:
$field = Field::find(1);
// Gets the specific subtype
$fieldable = $field->fieldable;
I'm tinkering with Neo4j 2.3.0 and Laravel 5.1 using NeoEloquent. I've set up a couple of dummy nodes and some relationships between them:
image of Neo4j model - apologies, I cannot insert images directly yet :)
So articles can use a template. The inverse of this relationship is that a template is used by an article.
I've set up the classes like so:
Class Template extends Model
{
public function articles()
{
return $this->hasMany('App\Article', 'USED_BY');
}
}
And:
Class Article extends Model
{
public function template()
{
return $this->belongsTo('App\Template', 'USES');
}
}
So far, so good, I think.
I have a page where I am wanting to eventually list all of the articles in the system, along with some useful metadata, like the template each ones uses. For this, I have set something up in the controller:
$articles = array();
foreach (Article::with('template')->get() as $article) {
array_push($articles, $article);
}
return $articles;
Not the most elegant, but it should return the data for both the article and it's associated template. However:
[{"content":"Some test content","title":"Test Article","id":28,"template":null},{"content":"Some flibble content","title":"Flibble","id":31,"template":null}]
So the question is - why is this returning null?
More interestingly, if I set up the relationship to the same thing in BOTH directions, it returns the values. i.e. if I change the USED_BY to USES, then the data is returned, but this doesn't make sense from an architectural point of view - a template does not 'use' an article.
So what am I missing?
More interestingly, if I set up the relationship to the same thing in BOTH directions, it returns the values.
That's correct, because this is how it operates. It is worth knowing that the relationship methods you have defined represent the relationship itself, which means for both models Template and Article to target the USED_BY relationship from any side it has to be the same in articles() and template.
The solution would be to use something like USES (or any notion you like) on both sides. This reference should help you make good decisions regarding your relationships.
On the other hand, if you still wish to have different relations on the sides then kindly note that in your model (image) both relationships are in outgoing direction. i.e. Fibble-[:USES]->Template and Template-[:USED_BY]->Fibble which means template() should be an outgoing relationship such as hasOne instead of belongsTo which is incoming.
Im getting various data out of my database.
Product::with('users');
I also have toe execute a complex raw query to get back some information. This is returned as an array.
In my method I would like to get products with users and then add on the data from my raw query to this collection, but this data comes back as an array. Something like:
Product::with('users');
Product->extraData = $rawQuery;
How can I add the raw query output to my Product Collection?
By using Eloquent Facade like Product:: you will get an Eloquent Model object as a result or an Eloquent Collection object as a result, including results retrieved via the get method or accessed via a relationship.
Now, if i understand correctly, you need to add a single extraData property to Eloquent Collection model alongside with Collection items? Or you need to add extraData for each Product ?
If you need to add additional property to Eloquent Collection object, maybe it is a good idea to use a Custom Collection. Please read this section: http://laravel.com/docs/5.1/eloquent-collections#custom-collections .
<?php namespace App;
use App\CollectionWithExtraData;
use Illuminate\Database\Eloquent\Model;
class User extends Model
{
public function newCollection(array $models = [])
{
return new CollectionWithExtraData($models);
}
}
And maybe your CollectionWithExtraData can have let's say a
public function setExtraData() {
}
or
public $extraData = array();
If you need extraData for each Product Eloquent Model, just create a new attribute within your Eloquent Model, make it public and set your extra data when needed. Make use of setExtraData() method and $extraData property from above