Laravel eloquent relationships user group posts - php

I am trying to get the users group, and include the post on that group.
This returns the users groups, but the groups must contain the posts of the group too. a post has group_id to where it is posted
My code to get the user:
return User::find(1)->groups;
My User model:
public function groups()
{
return $this->belongsToMany('Group');
}
My group model:
public function posts()
{
return $this->hasMany('Post');
}

You need to specify the relation to retrieve with your user, for example :
$user = User::with('groups')->find(1);
Also I would recomend to specify the keys in your relations for performance boost.
Also if you need nested with you can do this way:
$user = User::with('groups.posts')->find(1);
This will load User with groups and also posts in that group. It's stated in laravel docs. See this: eager loading

Here's what you need: return User::with('groups', 'groups.posts')->find(1);
Check out nested eager loading at the bottom of the section on http://laravel.com/docs/eloquent#eager-loading

Related

Calling Laravel relationship with aggregate

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;

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();

Get Table values using Eloquent Model in Laravel5

I want to find username from post_id using Post_Tag table using Eloquent model. Here are the tables.
User Table
user_id(pk)
username
Post Table
post_id(pk)
user_id(fk)
Post_Tag Table
post_id(fk)
Tag_id(fk)
How can I fetch username from User table using Post_Tag table. Here is what I have tried:
class Post extends Eloquent {
public function user() {
return $this->belongsTo('App\User');
}
}
class PostTag extends Eloquent {
public function post() {
return $this->hasMany('App\Post');
}
}
$posts = PostTag::with('post')->where('tag_id','=','20')->get();
One tag belongs to Multiple posts and each post will belong to an owner/User. Thank you in advance.
If your relations are working this would do it:
PostTag::find(20)->post()->first()
->user()->first()->username;
You say one Tag belongs to many posts, how do you choose which of the many posts you want to get the user's username?
Do you want to get all the users who have a post with some PostTag?
Edit: Try this:
PostTag::find(20)->with(['post', 'post.user'])->get();
Run this in artisan tinker or dd the result so you can see what is returned, I think this solves your problem. Just note that this may return a lot of data, you could use take instead of get to limit the results.

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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