I am trying to select specific columns using Laravel's Eloquent but I am having some issues. I just want to SELECT quantity, prices from prices. I have tried
$prices = Price::select(array('quantity', 'price'))->whereMonthAndYearAndType($month,$year,'cpi')
->with(array('product'=>function($query){ $query->select('id','name'); }))
->with(array('market'=>function($query){ $query->select('id','name'); }))->get();
but I am getting Trying to get property of non-object
There is nothing in your code snippet that would produce that error. However, I suspect you are getting the error when you are trying to access fields on the eager loaded product or market relationships without checking for their existence.
A common problem with specifying select statements and eager loading relationships is that the local and foreign keys usually get left out. However, these are the values that Laravel uses to match up all the related models, so they need to be selected, as well.
If price belongsTo a product and price belongsTo a market, then you also need to select the prices.product_id and prices.market_id fields. If price hasOne product or price hasOne market, then you'll need to select the prices.id field, and the corresponding foreign keys on the eager loaded relationships (products.price_id or markets.price_id).
Though, even once this is resolved, it is still a good idea to check to make sure the related record exists before trying to access it. In a hasOne/belongsTo relationship, if the related record doesn't exist, the relationship property will be NULL. If you try to access a field on NULL, you'll get the error you're seeing.
Related
I am making a multi-vendor ecommerce website using Laravel 7. I am trying to make an Order History page where in a single can user can view only his/her own orders. I am having a problem building the query on my OrderHistoryController. These are the codes on my controller:
$users = User::get();
$orders = Order::find($users);
return view('order-history', compact('orders'));
And I'm trying to loop $orders on my blade file. I have:
#foreach ($orders as $order)
<div>{{ $order->id}}</div>
<div>{{ $order->grand_total}}</div>
#endforeach
I am trying to pass the order id and order grand total to my view. I don't get any error however it shows a different order details from a different customer. How do I do this?
You should use MySQL (or any other database you are using) table relationships and foreign keys.
So, your orders table, should have columns id, user_id, date, and so on. The important thing is user_id column. You want to make that column a foreign key. That basically means that user_id will hold an id value from another table, in this case user. See how to make foreign key columns in laravel migrations here.
Next up is to use Laravel's built in model relationships. You can read more about them here. Basically, in your orders model you want to have a function user which returns $this->belongsTo(App\Models\User::class) and in your user model you want to have a function orders which returns $this->hasMany(App\Models\Order::class) (or whatever the namespace is for both of them).
That way, you can call $user->orders and get a collection of Order models which will contain only the orders of that particular user.
Definitely read the documentation carefully and learn basic concepts of the framework first and how relational databases function!
You can get a lot of this information just by googling it or reading the documentation of Laravel or any other framework you plan on using! Good luck learning :)
Laravel Version: 5.5
PHP Version: 7+
Database Driver & Version: mysql 5.7+
Scenario:
I have a SaaS application that has flexible database structure, so its fields are bound to change, especially given it has a Json field (for any extra database structure to be created from client side of the application), including relationship based fields. so Account Table can have dynamically created employee_id field, and thus the need to access relationships dynamically
Problem:
I need to EagerLoad models based on this dynamic relationship. If I had something like this:
// Account Model
public function employee(){
return $this->belongsTo(App\Employee);
}
it would be easy. But what I have is this:
public function modelBelongsTo(){
return $this->belongsTo($dynamicClassName, $dynamicForeignKey);
}
Now if I eager load this, I'll get Account Model instance with related Employee on key modelBelongsTo. This is how Eloquent Names based on the function of eagerload. But after this I cannot use this function again to eagerload a second model because it'll just overwrite results on modelBelongsTo key.
Possible Solution Directions:
1) Can I Somehow change laravel's process to use a name I provide?
or
2) Can I write functions on the fly to overcome this so I'll write employee function on the fly?
or
3) Worst Case Scenario: I iterate over all records to rename their keys individually because I am using a pagination, it wouldn't that big of a deal to loop over 10 records.
Us a morph relationship
define the various dynamic classnames say
Employee
Boss
Morph works by having the related key and the table name stored in the parent table, it means to relate them you have to use a join or an orm and you cant have foreign key constraint on it as it links to different tables.
then have your account have morphs where
we have
Account
as top class
then we have
EmployeeAccount, BossAccount
which have their relation to boss and employee
then in Account have morphto relation call it specificAccount()
to which in its child morphs have the morph relation to Account
then add it to $with so to eager load them so when fetching account you could simply do
$account ->specificAccount
to get its morph child. which is nullable
This is totally dynamic such that if you have other classes in future you can just add and add the morph relationship. This may be applied to any reflection or runtime evaluated and loaded classes/code though it is not advisable to do this, as you can always edit code to create new functionality without affecting previous.
Can I have column name and relationship name same?
example:
I have a column edited_by in mack.php model and I want to get full details of user mentioned in edited_by from users table so i have relationship like below
public function edited_by(){
return $this->hasOne('App\User','id','edited_by');
}
now, if i try to access $model->edited_by->first_name its throwing error 'trying to get property of non-object'
is there any way to fix it other than having different names?
The short answer is no. You can't have them be the same name because the column will always be returned if found and the relationship will never be returned if a column is found with that name.
Changing the column name to user_id would be more appropriate than edited_by. It's more descriptive, and it's also the default id that Eloquent will look for. Similarly the relationship name makes more sense being named user() rather than edited_by() because it returns a user Model.
The slightly longer, and totally incorrect answer is that you can access the relationship with $model->edited_by()->first_name this will result in extra queries being run unnecessarily though.
I have this schema
All the relations here must be one-to-zero/one.
A user can be either an employee or a customer. The user_type ENUM gives me the type so I know where to go from there.
Then an employee can be either basic or a manager. The employee_type discriminator let's me know that.
How am I supposed to build the Eloquent Model relations?
Let's say I have a user that is an employee. I need to get it's common fields from the users table but also need to get common fields from employees table. Do I need to hard code, and know that when user_type=emp I need to select from the employees table? What if I need to add another user type later?
UPDATE
Would it make sense to change my schema into something simpler?
My problem is that by using, as suggested, polymorphic relations I would end up to something like this:
$user = new User::userable()->employable()->...
Would a schema in which I drop the employees table and have employee_managers and employee_basics linked straight to the users table?
this is an polymorphic relationship. but if you want to be easy, you need to fix some things.
in the table employees
- user_id
- employable_id
- employable_type enum(Manager, Basic) # References to the target model
.... this last two are for the polymorphic relation, this is the nomenclature
in the basics and managers table you could delete the user_id field, but you need an id field as increments type
and now in the model Employee you need to make this function
public function employable(){
return $this->morphTo();
}
I hope this works :)
I want to design an online store. For each category of productions, we would have its own fields.
Connections between tables of fields and categories are done and displayed in the part of registration of productions.
At the end, the value of each field should be stored that it should contains the related table between table of fields and productions (in addition to/plus/+) the value of that field.
My problem is in this part and I want that this related table has an additional field that I could value it.
In the following figure, the picture of table and my connections are shown, if there is (any problem/ something wrong with it), I would appreciate you to help me.
View Relationship Images :
http://ir-up.ir/uploads/1416568805731.jpg
You'd simply need to add a withPivot when declaring the relationship:
return $this->belongsToMany('Role')->withPivot('foo', 'bar');
Extra attributes in pivot tables are covered in the docs, here - http://laravel.com/docs/4.2/eloquent#working-with-pivot-tables