Querying on related models using Laravel 4 and Eloquent - php

Using Laravel 4 I have the following models and relations: Event which hasMany Record which hasMany Item. What I would like to do is something like this
Item::where('events.event_type_id', 2)->paginate(50);
This of cause doesn't work as Eloquent doesn't JOIN the models together when retrieving the records. So how do I go about this without just writing the SQL myself (which I would like to avoid as I want to use pagination).

What you want is eager loading.
It works like this if you want to specify additional constraints:
Item::with(array('events' => function($query) {
return $query->where('event_type_id', 2);
}))->paginate(50);

There is a pull request pending here https://github.com/laravel/framework/pull/1951.
This will allow you to use a constraint on the has() method, something like this:
$results = Foo::has(array('bars' => function($query)
{
$query->where('title', 'LIKE', '%baz%');
}))
->with('bars')
->get();
The idea being you only return Foos that have related Bars that contain the string 'baz' in its title column.
It's also discussed here: https://github.com/laravel/framework/issues/1166. Hopefully it will be merged in soon. Works fine for me when I update my local copy of the Builder class with the updated code in the pull request.

Related

laravel elequent way to find single row from table

hello I am new to laravel and maybe I am a bit confused between eloquent and query builder way for writing a query but anyway can you please tell me what could be the best eloquent way to retrieve info like this in laravel 6 or 7
User > hasMany > Recipes
Recipe > belongsTo > User
I want to check if user id 2 present in users table then get only one post which id is 3
Query builder is for explicitly building SQL queries, and does not return instances of your models. Eloquent query builder, is similar but the result will contain the model(s) loaded with all their attributes, and has some handy functions for querying the relations you define in your models.
Given the limited information in your post, I am assuming when you say a post, you mean a recipe:
Query Builder:
DB::table('users')
->join('recipes', 'recipes.user_id', '=', 'users.id')
->select(['users.some_col', ... 'recipes.some_col'])
->where('users.id', 2)
->get();
If you have your models setup with the relations. You can use Eloquent like so:
User::where('id', 2)->with('recipes')->get();
If I understand you correctly it would be like this:
User::whereId($userId) //asuming it is 2
->with(['recipes' => function($q) use($recipeId) {
$q->where('id', $recipeId); //assuming it is 3
}])->first();
you can do this if i understand correctly:
$user = User::findOrFail(2); //auto 404 if user not found
$recipe = $user->Recipes()->where('id',3)->first();
You may use conditional eager loading for better performance.
$userId = 2;
$receiptId = 3;
$user = User::with(['receipts'=> function ($query) use($receiptId){
$query->where('id', $receiptId);
}
])->find($userId)

loading relationship with groupBy laravel

I have a query which selects some relationships and groups by the accommodations to remove the duplicate accommodations. But now when I want to load the discount realtion on rooms, it doesn't work because I select only the accommodation_id.
Here is my code:
$data = AccommodationRoom::with('accommodation.city', 'accommodation.accommodationFacilities', 'accommodation.gallery','discount')
->select('accommodation_id')
->whereHas('roomCapacityHistory', function ($query) use ($from_date, $to_date) {
$query->whereDate('from_date', '<=', $from_date);
$query->whereDate('to_date', '>=', $to_date);
})
->whereHas('accommodation', function ($query) use ($searchCity) {
$query->where('city_id', $searchCity);
})
->groupBy('accommodation_id')
->get();
Now if I add the id to the select it would be fine, but my groupBy doesn't work and gives me an error in this case. So I need a solution to get all my accomodations with the listed relations.
As you are looking for all your accommodations with some related models, you should actually select from your Accommodation model. This will work out of the box for the first three relations but will require some tweaking for the discount relation. The simpliest solution is to create a HasManyThrough relation on the Accommodation model:
class Accommodation extends Model
{
public function discounts()
{
return $this->hasManyThrough(Discount::class, AccommodationRoom::class);
}
}
Note: this expects your models to use foreign key columns named by convention; for different names you will need to pass the custom foreign key names as additional parameters according to the documentation.
With this relation set up, you can then use a query like the following:
$data = Accommodation::with('city', 'accommodationFacilities', 'gallery', 'discounts')
->whereHas('accommodationRooms.roomCapacityHistory', function ($query) use ($from_date, $to_date) {
$query->whereDate('from_date', '<=', $from_date);
$query->whereDate('to_date', '>=', $to_date);
})
->where('city_id', $searchCity)
->get();
Further explanation as asked for in the comments:
HasManyThrough builds a virtual relation between two models using a third model in between. Imagine you have Post, Comment and Like as models. One Post can have many Comments and one Comment can have many Likes:
has many has many
Post -----------------> Comment -----------------> Like
1 n 1 n
In this case we also know that one Post can have many Likes. And this is exactly the knowledge we utilize when using HasManyThrough. We simply tell Eloquent that a Post has many Likes, connected by the Posts in between:
has many has many
Post -----------------> Comment -----------------> Like
1 n 1 n
has many through Comment
Post ------------------------------------------------> Like
1 n

How to add a condition in Eloquent query based on related model data?

If you have a query that uses eager loading like this:
Brand::with('tags')
->where('id', $id)
->get();
A brand can have many tags.
I then also have an array of tag ids like this [2,4]. How do I add a condition to this query where it returns only those brands whose tags are in the array?
I tried the eager load constraints but that condition is then placed on the tags model, not the Brand.
I tried this also but it returns an unknown method error:
public function tagsIn($allTags){
return $this->belongsToMany('App\Tag', 'brand_tags')
->whereIn('tags.id', $allTags);
}
Brand::with('tags')
->tagsIn('[2,4]')
->get();
I suspect a possible limitation to getting it to work is the fact that Eloquent makes two separate database calls. But is there a way nevertheless?
DB::table('Brands')
->join('brand_tag','brands.id','=','brand_tag.brand_id')
->join('tags','brand_tag.tag_id','=','tags.id')
->whereIn('tags.id',$allTags)
->get();
Try this DB::table('name')->whereIn('column', array(1, 2, 3))->get();
I think you should use this package to handle tag. I used it in my projects. laravel-tagging

Laravel 4 - Eloquent way to attach a where clause to a relationship when building a collection

This may be a dupe but I've been trawling for some time looking for a proper answer to this and haven't found one yet.
So essentially all I want to do is join two tables and attach a where condition to the entire collection based on a field from the joined table.
So lets say I have two tables:
users:
-id
-name
-email
-password
-etc
user_addresses:
-address_line1
-address_line2
-town
-city
-etc
For the sake of argument (realising this may not be the best example) - lets assume a user can have multiple address entries. Now, laravel/eloquent gives us a nice way of wrapping up conditions on a collection in the form of scopes, so we'll use one of them to define the filter.
So, if I want to get all the users with an address in smallville, I may create a scope and relationships as follows:
Users.php (model)
class users extends Eloquent{
public function addresses(){
return $this->belongsToMany('Address');
}
public function scopeSmallvilleResidents($query){
return $query->join('user_addresses', function($join) {
$join->on('user.id', '=', 'user_addresses.user_id');
})->where('user_addresses.town', '=', 'Smallville');
}
}
This works but its a bit ugly and it messes up my eloquent objects, since I no longer have a nice dynamic attribute containing users addresses, everything is just crammed into the user object.
I have tried various other things to get this to work, for example using a closure on the relationship looked promising:
//this just filters at the point of attaching the relationship so will display all users but only pull in the address where it matches
User::with(array('Addresses' => function($query){
$query->where('town', '=', 'Smallville');
}));
//This doesnt work at all
User::with('Addresses')->where('user_addresses.town', '=', 'Smallville');
So is there an 'Eloquent' way of applying where clauses to relationships in a way that filters the main collection and keeps my eloquent objects in tact? Or have I like so many others been spoiled by the elegant syntax of Eloquent to the point where I'm asking too much?
Note: I am aware that you can usually get round this by defining relationships in the other direction (e.g. accessing the address table first) but this is not always ideal and not what i am asking.
Thanks in advance for any help.
At this point, there is no means by which you can filter primary model based on a constraint in the related models.
That means, you can't get only Users who have user_address.town = 'Smallwille' in one swipe.
Personally I hope that this will get implemented soon because I can see a lot of people asking for it (including myself here).
The current workaround is messy, but it works:
$products = array();
$categories = Category::where('type', 'fruit')->get();
foreach($categories as $category)
{
$products = array_merge($products, $category->products);
}
return $products;
As stated in the question there is a way to filter the adresses first and then use eager loading to load the related users object. As so:
$addressFilter = Addresses::with('Users')->where('town', $keyword)->first();
$users= $addressFilter->users;
of course bind with belongsTo in the model.
///* And in case anyone reading wants to also use pre-filtered Users data you can pass a closure to the 'with'
$usersFilter = Addresses::with(array('Users' => function($query) use ($keyword){
$query->where('somefield', $keyword);
}))->where('town', $keyword)->first();
$myUsers = $usersFilter->users;

Laravel ORM "with" is returning all rows even with constraint

Using Laravel 4 Eloquent ORM, any idea why the following is pulling every row instead of just the one I'm asking for (book_id=3)?
if ($Book = Book::find(3)) {
return (Book::with(array('chapters.pages' => function($query)
{
$query->where('book_id', '=', 3 ); // hard-coded id for illustration purposes
})
)->get()->toJson());
}
The output I'm getting is every single book with every chapter and every page. I only want to pull that single book with chapters and pages.
According to the documentation I should be able to add a constraint. Seems like I'm following the docs pretty closely. Thanks in advance.
I think the problem is you are asking for Book::with() - but you have not put a constraint on the Book() itself. So you need to do Book::with()->where()
Does this work
Book::with(array('chapters.pages' => function($query)
{
$query->where('book_id', '=', 3 ); // hard-coded id for illustration purposes
})
)->where('id', '=', '3')->get()->toJson());
note the ->where() - which is putting the id constraint on the query.
Edit: if you have correctly defined relationships (such as HasMany() etc) - then this should work:
$books = Book::with('chapters.pages')->where('id', '=', '3')->get();
Because the relationship with mean it only gets the 'chapters/pages' for the book with id of 3 by defintion.

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