I've two tables user and product, along with their relationship user_product. The relationship table contains an extra field category. Now I want to find
the number of products selected by a user of a particular category.
I've done it in my page through coding. Is there any easier way to do this?
How to use field of pivot table?
you can use withPivot
Ex:
$this->belongsToMany('Role')->withPivot('foo', 'bar');
Related
Hello I am working with Laravel,
I have to create two simple models, let's say Stores and Books.
Stores can have one or multiple Books and Books can belong to many Stores.
Of course I will use a many to many relationship, with a pivot table.
Books the can have different prices depending the store.
I think a separate table can only complicate things, in my mind the pivot table associating books and stores should have a price column, but pivot tables only contains store_id and book_id.
Should I create a book_prices and associate it with books and to stores? What is the best approach?
You are free and able to set other attributes on your pivot table. You can read more about it in the docs.
https://laravel.com/docs/9.x/eloquent-relationships#retrieving-intermediate-table-columns
You have to define the relationship accordingly, the following should clarify how this works. In this example you use the many-to-many relationship and add the price column to every retrieved pivot model.
public function books()
{
return $this->belongsToMany(Book::class)
->withPivot('price')
}
For example, you are able to access the pivot column in a loop like this
foreach ($shop->books as $book)
{
echo $book->pivot->price;
}
You can define additional columns for your pivot table in the migration for the pivot table, and then when defining the relationship use withPivot to define the additional columns so they come through in the model:
return $this->belongsToMany(Book::class)->withPivot('price');
(Adapted from the Laravel documentation, see https://laravel.com/docs/9.x/eloquent-relationships#retrieving-intermediate-table-columns)
Depends on the complexity of your case, but yes, you have two options for it. Let's say that the pivot table is called as book_store:
Directly adds price column to book_store. This is obviously the simpler option. The drawbacks are:
The history of the price changes isn't logged. You'll have to create another table for logging if you want to keep this history information.
Changes made to price will directly change the price of the related book_store record. Meaning that a price is being updated "live" e.g users cannot update the price now but "publish" it some time later just like this example in the doc.
Create a new, different table to store the price. This may seems relatively more complex, but it may also be more future-proof.
Basically, you get 2 things that you miss in the first option above.
Don't think too much about book_store being a pivot table. One way to see it is like this: book_store IS a pivot table from books and stores tables viewpoints, but it's also just a normal SQL table which could relate to any other tables using any kind of relationships.
If you want to implement this, make sure to create a primary-key in the book_store table.
Alast, it all depends on what you need. Feel free to ask if you need more insight about this. I hope this helps.
Is it possible to use Laravel Backpack relationship field type with both inline_create and pivot fields enabled?
I'm trying to make this happen:
I have 2 entities, Products and Productions, and both have a belongsToMany relation defined in the model. Therefore they have a pivot table with product_id and production_id.
In this pivot table I have a count column.
With Backpack I'm trying to solve the following:
I want to fetch products on productions create operation, or create product from this view and specify the pivot field count with it.
If I remove the 'subfields' property from the field definition, the add field button shows up.
I've attached 3 screenshots of the mentioned functionality.
Product with Add, but without count field
Clicked on "Add" - Modal opened
Product with count pivot field and without Add
Hello #roamingTurkey !
You should be able to do it, but you need to configure your pivotSelect key in your n-n field definition : https://backpackforlaravel.com/docs/5.x/crud-how-to#extra-saving-additional-attributes-to-the-pivot-table
Let me know!
I have a table customers with the fields id, name and so on.
One table doctors with the fields id, name.
Then there is one table subject_areas which has all subject areas which a doctor can have. The fields are id, text.
So, each doctor can have multiple subject areas. There is one pivot table doctor_subject which is a belongsToMany relation.
Here is my problem: A customer can have multiple doctors, but only for a specific subject area. I tried it with a new table customer_doctor with the fields id, customer_id and doctor_subject_id. But how do i map this in Eloquent?
Issue was in relation between tables. After chat clarification this came out as solution:
Html form is written in a way that customer first choose doctor, then depending on selection choose several of his available areas.
In that scenario customer needn't to be related to areas directly and should be related to areas only over relation with doctor.
Also as side note, if needed deeper relations, models on pivot tables could be created and used as well.
I have relation many to many (posts and tags) in Eloquent. Is it possible to order tags in the pivot table to get 10 most commonly used tags?
Yes it is possible, add some kind of attribute (to the pivot table and update it upon every select from the database. (increment the value)
And when selecting use wherePivot method.
If you want "most recent used", add timestamps to the pivot table in your migration and touch pivot table on every select.
Yes it is actually very simple to do that.
In the table that you store your tags add another column called count_cache(or whatever you want), then every time you add a tag instance to a post instance do a count() of the tag_id in the pivot table and store the value to the count_cache column in the tags table.
Then you can simply get the tags table ordered by the count_cache collumn (descending) with a limit of 10.
If you need further explanation please make a comment :)
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