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I want to get Id from students table where i want insert this id in differs table . I don't really know how to explain it but maybe if you see my codes, you would understand. I have already finish making the relationship between this 2 tables already
my student controller
this my differ controller but I do not know any idea about if this code true or no
first: 'app\Differ'? but Differ is in App\Models
you can use hasOne(Differ::class); when Student model and differ in the same folder
the second thing you should know, when using functions of relationship in laravel such as hasOne, a foreign key should be named by student_id in Differ or
you show it in function like hasOne(Differ::class,'id_student','id')
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.
I'm trying to figure out if there's some way to get the values of two columns in a pivot table, based on a unique incrementing ID that I gave each row.
I have a Job model, a Location model, and an Application model.
The Job and Location have a many to many relationship with a pivot table "job_location". The two foreign keys it contains are job_id and location_id. However, I also gave every row a unique incrementing ID, jobloc_id.
If I only have the jobloc_id, how can I look up the values of the other two columns?
$jobLoc = $location->jobs->wherePivot('jobloc_id', '=', 1);
return $jobLoc->job_id;
Returns "Method wherePivot does not exist" even though I've seen references of people using it. All I have is the jobloc_id, and am trying to lookup the other two values based on this so that I can fully load the Job and Location to pull attributes from them.
Any pointers would be greatly appreciated. This is in Laravel 5.3.
If you're added ID to pivot table (jobloc_id for example) and you want to get row by ID, just use query builder:
DB::table('job_location')->where('jobloc_id', 1)->first();
That's the fastest and simpliest way to do that when you have unique row ID in the pivot table.
I have a first table named "Building", and this one gets a Type and a Level. There are multiple building with same type and level.
I have another table named "BuildingInfo", who also gets a Type and a Level. The couple Type/Level is unique on this table.
Is there a way to have a HasOne relationship on Building, giving me the matching BuildingInfo ? The problem being that there are two keys on each table to get it, and I can only specify one key for each table with HasOne().
Thank you.
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 know how to handle mysql tables created with constraints in joomla.
for a example,
theater_table
id , name, description, image, address, tel, fax ,email
theater_facility_table
id, theater_id, facility_id
facility_table
id, name, description, image
Facility table already filled with data and id is the primary key. When creating a theater I am adding facilities to it. I created facility and theater JTables.
Do I have to create theater_facility JTable too?
Using theater Model class how I insert data to theater_facility table. I know I can insert data after theater stored successfully creating and calling storeTheaterFacility() method where it contains insert query to save required information. But I feel it can't be a good method to do so. Please help me to solve this.
Depending on how you implemented the theater - facility relationship, you can handle insering new data in different parts of your code. I mean, if for example your JTable class (the one that loads theaters) is loading/saving the theater-facilities relationship too, then the same class should delete it.
May be you can take a look at other components (for example, com_content, which relates an article to a category, or K2, where you can have multiple tags related to multiple "items"(articles)), so you can take a look on how do these components handle these kind of relationships.
Another important point you shouldn't forget is to update your facility model / table to delete records from the relationship table upon facility deleting.
I hope it helped!