Calling Laravel relationship with aggregate - php

If I have a Laravel 5.5 model called User that hasMany Posts and each Post hasMany Hits, is there an aggregate function I can call to get the total number of Hits for a User across all Posts, where the Hit was created in the last week?
It seems like there may be a clever way to do it besides doing something like
$hits = $user->posts()->hits()
and then looping over those hits to check created date.
In this case it seems like raw sql would be better, but I figured there may be an Eloquent way to handle a situation like this.

I think the right solution is just to use a HasManyThrough relationship to grab all the Hit rows, joined through the posts table.
So it'd look like this on the User model (roughly):
return $this->hasManyThrough(
Hit::class,
Post::class
// if you have non-standard key names you can specify them here-- see docs
);
Then when you have your User model you can just call $user->hits to get a collection of all the associated hits through all the user's Posts

You can add the code below to your Post model.
protected static function boot()
{
parent::boot();
static::addGlobalScope('hitCount', function ($builder) {
$builder->withCount('hits');
});
}
It automatically provides a field hits_count whenever you fetch a post.
$post = Post::first();
$hits = $post->hits_count; //Count hits that belongs to this post
You can read the documentation here to customize it to your need.

Set HasManyThrough relation in the User model:
public function hits()
{
return $this->hasManyThrough('App\Models\Hits','App\Models\Posts','user_id','post_id','id');
}
then you can do this:
$reults = $user->hits()->where('hits_table_name.created_at', '>=', Carbon::today()->subWeek())->count();
HasManyThrough Link
Use DB::enableQueryLog(); and DB::getQueryLog(); to see if executed SQL Query is correct;

Related

Trying to get data via related table in Laravel

What I'm trying to do is to show the posts that have been saved by the user in the profile. I will try to explain it as good as possible refering to my code. So:
public function userProfil($id)
I have the profile function which get the data from userprofile table. and inside I have the following code for saved data:
$authed = User::find($id);
$savedarticles = $authed->mysaves;
$allsavings = DB::select("Select * from article where id=$savedarticles->id");
But this code does not work like this anyway. I can do this instead:
$authed = User::find($id);
$savedarticles = $authed->mysaves;
But when I try to get articles from article table with the article_id of mysaves, it does not work such as this:
$allsaved= DB::table('article')->where('id', $savedarticles->article_id);
the error it gives is like:
Property [article_id] does not exist on this collection instance.
although savearticle table has article_id I can output it without the line above and in view I get them as:
#foreach($savedarticles as $savedarticle)
<p>{{$savedarticle}}</p>
#endforeach
it gives me everything that is in the savearticle table and I can get do savedarticle->article_id and get article_id but can't get it in controller.
I am using Laravel 5.4.
The error message Property [article_id] does not exist on this collection instance. means you are trying to get an attribute of a single instance but from a collection.
For example the collection could be like
[$article1, $article2, $article3]
therefore what you tried to do is something similar to
[$article1, $article2, $article3]->article_id
You are trying to get an attribute from a collection instead of a single instance.
As for your query, you can use where in sql statement to search for rows that match any item in an array
$allsaved= DB::table('article')->whereIn('id', $savedarticles->pluck('article_id')->all());
What I have understood is that A USER has many POSTS and a POST belong to an article.
If this is true then you have to do following.
1: In USER model define a relation to get all posts. like below.
public function posts() {
// Foreign key will be a key that is stored in posts table and represent the user MAY BE: user_id
$this->hasMany(Posts::class, 'foreign_key', 'local_key')
}
This will allow you to get all posts belong to a user.
2: In posts, model defines a user relation like below.
public function user() {
$this->belongsTo(User::class, 'foreign_key', 'local_key');
}
This will allow you to get a post User;
3: Now in your controller you will have something like this.
public function show($user_id) {
// find a user with posts as eager loading(to avoid query again)
$user = User::with(['posts'])->where('id', $user_id)->first();
// get all posts that belong to this user
$posts = $user->posts;
}
In controller show($user_id) method you will have a user data as well as user posts data. Now if you want to get a post relations then simply define as below. let say a post belongs to an article as well.
4: In posts, model defines a relation to get an article.
public function article() {
// This will allow you to get a post artcle
$this->belongsTo(Article::class, 'foreign_key', 'local_key');
}
Now you can get the article as well while finding a user. please see below. I am rewriting controller show action to give you a better understanding.
5: Get a user with user_id
public function show($user_id) {
// find a user with posts as eager loading(to avoid query again)
// eager loading for posts & post child, this will give you NOSQL at runtime and all data will come from one query.
$user = User::with(['posts', 'posts.article'])->where('id', $user_id)->first();
// get all posts that belong to this user
$posts = $user->posts;
foreach($posts as $post) {
$article = $post->article; // Child relation of post.
}
}
Hope you will understand the flow, you have to make sure models relation to work it perfectly. If you need further help please let me know.

Eager load ONE from Many to Many relationship

I have a many to many relationship for users and roles. A user can have multiple roles, but I only want with to grab the FIRST role.
Consider the following code:
User::with('roles')->get()
Works great for all roles, but I only want the first role.
I've set this up in my model but doesn't work:
public function role()
{
return $this->roles()->first();
}
How do I load with for only the first result?
You should be able to call first directly on the eager loaded relationship like this:
User::with(['roles' => function ($query) {
$query->first();
})->get();
first() actually executes the query and returns the results as a collection. Relationships must return a query builder, which can then be chained or executed, so using first() in a relationship won't work.
UPDATE
I realised you want to use role in with, so you need to create a relationship to do that. Create a new relationship on your User model (you can use any limit described in the docs, not just oldest()):
public function role()
{
return $this->hasOne('App\Role')->oldest();
}
And then you can use it in with:
$users = User::with('role')->get();

Laravel Eloquent query unexpected result

I've found some query result really unexpected.
It's Laravel 5.2
We have following entity:
User with method:
public function roles() : BelongsToMany
{
return $this->belongsToMany(Role::class)->withPivot('timestamp');
}
Each User can have many roles, so we have also Role entity (but it doesn't matter much in my question) and pivot table user_role with timestamp field (and ids of course), because we hold information about time, when User achieved specific role.
I want to get all Users with theirs last assigned Role
When I create query (in User context in some repository):
$this->with(['roles' => function($query) {
$query->orderBy('timestamp', 'desc');
}])->all();
the result will contain Users with Roles entities inside itself ordered by timestamp - it's ok. But I want to retrieve only one last role inside each User entity not all ordered.
So...
$this->with(['roles' => function($query) {
$query->orderBy('timestamp', 'desc')->limit(1);
}])->all();
And then I retrieve Users but only User which achieved some Role for the very last time contains it! All the other Users have their roles field containing empty array.
Why ordering was performed on each Users relation separately, but when I added limit it behaved like a global limit for all.
It drives me crazy...
Thanks for advices.
EDIT
I've created lastRoles() method to get all Roles ordered desc. But all, retrieving one is impossible.
public function lastRoles() : BelongsToMany
{
return $this->BelongsToMany(Roles::class)->withPivot('timestamp')->latest('timestamp');
}
And for testing:
$users = (new User())->with('lastRoles')->get();
But now I must iterate over Users and invoke lastRoles() on each one:
foreach ($users as $user) {
var_dump($user->lastRoles()->get()->first()->name);
}
Then I retrieve names of latest Roles assigned to each User.
So... There is no way to do it in one query? This is the only way?
For this to work, you would need a helper function:
public function latestRole()
{
return $this->hasOne(Role::class)->withPivot('timestamp')->orderBy('timestamp', 'DESC');
}
And then:
$this->with('latestRole')->get();
Credits to this awesome article.
When you eager load a relationship with query constraint(s), the query will be run once to load all relationships, not each one individually. This is the expected behavior. Think about it, eager loading exists to turn many queries into one query in order to optimize performance. There is only one query executed, so your limit constraint will limit the entire result set, rather than on a per model basis.
To circumvent this, you could try creating another belongsToMany method that adds the desired limit constraint. The following code is untested:
public function lastRole() : BelongstoMany
{
return $this->belongsToMany(Role::class)
->withPivot('timestamp')
->orderBy('timestamp', 'desc')
->limit(1);
}
Assuming this works, you can then simply change the relationship method from roles to lastRole and remove your query constraint:
$this->with('lastRole')->all();

Fetching and filtering relations in Laravel Eloquent

I have the following models in Eloquent: groups, threads, comments and users. I want to find all comments in a specific group from a specific user.
This is my current approach:
$group->threads->each(function ($thread) use ($user_id)
{
$user_comments = $thread->comments->filter(function ($comment) use ($user_id)
{
return $comment->owner_id == $id;
});
});
This looks ugly as hell, is probably slow as hell, and I just want to get rid of it. What is the fastest and most elegant way in Eloquent to get to my result set?
If a group hasMany threads, and a thread hasMany comments, you can add another relationship to group: group hasMany comments through threads.
On the group:
public function comments() {
return $this->hasManyThrough('Comment', 'Thread');
}
Now, you can get the comments in a group by $group->comments;
From here, you can tack on the requirement for the user:
$user_comments = $group->comments()->where('owner_id', $user_id)->get();
If you want, you can extract the where out into a scope on the Comment.
patricus solution pointed me in the right direction. I cross posted my question to the laracasts Forum and got a lot of help from Jarek Tkaczyk who also frequently visits this site.
hasManyThrough() for the Group model is the way to go:
public function comments()
{
return $this->hasManyThrough('ThreadComment', 'Thread');
}
There a couple of caveats, though:
Use the relation object instead of a collection ($group->comments(), NOT $group->comments)
If you use Laravel’s soft deletes you can’t just change the get() to a delete(), because you’ll get an ambiguity error for the column updated_at. You can’t prefix it either, it’s just how Eloquent works.
If you want to delete all comments from a specific user in a specific group you’ll have to do it a little bit differently:
$commentsToDelete = $group->comments()
->where('threads_comments.owner_id', $id)
->select('threads_comments.id')
->lists('id');
ThreadComment::whereIn('id', $commentsToDelete)->delete();
You basically fetch all relevant IDs in the first query and then batch delete them in a second one.

Eloquent where owner equals follow

I am trying to make a twitter like feed in an application, I have a database called connections where inside there's user and follow and another database called feed containing owner which would equal to the follow column in connections.
What I could do if had every id of a follower statically is to use where('owner', '=' $follow) on each follower and return it.
I tried this approach but it wasn't ideal:
Get each follower inside connections;
foreach(follower) {
Get 10 of the latest posts orderBy "created_at";
Push into array;
}
shuffle array;
limit array to 15;
return array;
That also ended with the returned array not being ordered by created date.
How would I use eloquent to get the feed item only if the user follows the owner in the best/simplest way?
Are there any specific Laravel tools that can be used?
Also the database layout isn't fixed as it is, it can be altered if needed to better suite this.
You need to create a many-to-many relationship between the user and itself. See the laravel eloquent documentation http://laravel.com/docs/eloquent#relationships. I didn't test this code but it should be enough to get you started down the right track.
Create a pivot table called "user_following" with:
(int) id, (int) user_id, (int) following_id
Then do something like this:
<?php
// Model
class User extends Eloquent {
public function following()
{
return $this->belongsToMany('User', 'user_following', 'user_id', 'following_id');
}
public function tweets()
{
return $this->hasMany('Tweet')->orderBy('created_at', 'desc');
}
}
// controller
$tweetsOfWhoImFollowing = User::find($id)->following->tweets;

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