in my Laravel 5 application i have many to many relationship between two models.I'm using a pivot table to keep track of them. In my both models i have defined belongsToMany method with relevant pivot table name as parameter.Then i'm going to add values to the pivot table in controller. It works fine for only one column. For the other one it's not inserting any values. In the Controller i'm calling like this,
$this->mymodel->addToPivotTable($values);
Should i pass two parameters there?
I could able to solve this. I needed to call the method after saving my data set to the table.It's like this,
public function add(Request $request){
$post = $request->all();
$arr = array(1,4,5);
$result = $this->mymodel->create($post);
$result->classifications()->attach($arr);
}
Related
I have a Student model and a corresponding one to one mapping relationship to Result model.
I have an eligibleList array containing a list of student id whose marks are to be displayed. Some student have results while some does not have but i need to display all of them from the list.
I am able to retrieve and display students using the following:
$students = Student::with('result:student_id,marks')->whereIn('students.id', $eligibleList)->get();
foreach($students as student) {
if ($student->result != null)
Log::debug($student->result->marks)
else
Log::debug("-1") //-1 indicate no results
}
The above has no issue until i need to sort the list (ascending or descending) by the marks. I tried the following:
$students = Student::with(['result:student_id,marks' => function ($query) {
$query->orderBy('marks','DESC');
}])->whereIn('student.id', $eligibleList)->get();
It throws me a "Call to undefined relationship" error. Is there anyway to sort from the query ? I avoid sorting the collection as it can get very slow for thousands of records. Somehow eloquent early loading encounter some error when sorting with non existence relationship.
you should use 'Subquery Ordering', ordering inside 'with' will not sort the overall result.
$students = Student::with(['result:student_id,marks'])->whereIn('student.id', $eligibleList)
->orderByDesc(Result::select('marks')->whereColumn('student_id','students.id'))
->get();
https://laravel.com/docs/7.x/eloquent#advanced-subqueries
if you use laravel 5 you have to use 'join':
Student::with(['result:student_id,marks'])->whereIn('student.id', $eligibleList)
->join('result','result.student_id','student.id')
->select('user.*,result.marks')->orderBy('result.marks')->get();
'join' use table name not the relation name, so please be careful about table name in previous 'join' and 'select' statements
So, in order to check the existence of a relationship on a model, we use the has function on the relationship like model1->has('relationship1').
While it is possible to supply the model1->with() function with an array of relations to eager load them all, both has and whereHas functions do not accept arrays as parameters. How to check for the existence of multiple relationships?
Right now, I am running multiple has functions on the same model (The relations are not nested):
model1->has('relationship1')
->has('relationship2')
->has('relationship3')
But that is tedious and error-prone. Solution anyone?
There unfortunately isn't a way to pass an array of relationships to has() or whereHas(), but you can use a QueryScope instead. On your Model, define the following:
public function scopeCheckRelationships($query){
return $query->has("relationship1")->has("relationship2")->has("relationship3");
}
Then, when querying your Model in a Controller, simply run:
$result = Model::checkRelationships()->get();
The function name to use a Scope is the name of the function, minus the word scope, so scopeCheckRelationships() is used as checkRelationships().
Also, it's actually possible to pass the relationships you want to query as a param:
public function scopeCheckRelationships($query, $relationships = []){
foreach($relationships AS $relationship){
$query->has($relationship);
// Might need to be `$query = $query->has(...);`, but I don't think so.
}
return $query;
}
...
$result = Model::checkRelationships(["relationship1", "relationship2", "relationship3"])->get();
In case you need this to be dynamic.
Here's the documentation for Query Scopes if you need more info: https://laravel.com/docs/5.8/eloquent#query-scopes
I have a database composed by users, users_child, child.
I create a ONE to MANY relationship between Users and users_child, then i create a relationship between users_child and child. Now the below code work:
$test = users::find(1)->users_child
$test1= users_child::find(1)->child
Now i want to know if is possible to create a single row that link the three table like this:
$test = users::find(1)->users_child->child
I create the relationship in the model but in the db i don't create Foreign Key, it's a problem? on the model i specify the field for link table.
http://laravel.com/docs/5.1/eloquent-relationships#querying-relations
You can chain relationships like this:
$user = Users::with("users_child.child")->where("id",1)->first();
Each point will mean a relation stored in the first.
Out of users users_child will be taken and out of users_child child will be taken. (Relations)
foreach($user->users_child as $user_child) {
$user_child->child;
}
will get you the data you need.
I've got a many to many relationship between a student and an institution_contact.
students should only ever have two institution_contacts and I have an attribute on the pivot table named type to be set as 1 or 2.
So, my pivot table looks like this:
institution_contact_student: id, institution_contact_id, student_id, type
I've run into difficulty in deciding how to approach the issue of adding/updating the pivot table. Let's say I have 100 students and I want to assign them a contact with the type of 1.
My current solution is to delete the contact then add it:
$students = Student::all(); // the 100 students
$contactId = InstitutionContact::first()->id; // the contact
foreach ($students as $student) {
// remove existing contact
$student
->institutionContacts()
->newPivotStatement()
->where('type', 1)
->delete();
// add new contact
$student
->institutionContacts()
->attach([$contactId => ['type' => 1]]);
}
However, I'm thinking that this is going to hit the database twice for each student, right? So would I be better off creating a model for the pivot table and removing all entries that matched the student id and the type then simply adding the new ones? Or would creating a model for the pivot table be considered bad practice and is there a better way of accomplishing this that I've missed?
Please note the reason I'm not using sync is because I'm relying on the type attribute to maintain only two contacts per student. I'm not aware of a way to modify an existing pivot without causing issues to my two contacts per student requirement.
Edit:
Instead of creating a model I could run the following code to perform the delete using DB.
DB::table('institution_contact_student') // the pivot table
->whereIn('student_id', $studentIds)
->where('type', 1)
->delete();
If I have understood your question correctly then you can use the updateExistingPivot method for updating your pivot table.But first of course you have to define the pivot in your relationship. For instance,
public function institutionContacts(){
return $this->belongsToMany('institutionContact')->withPivot('type');
}
after this, all you have to do is use the following code:
$student
->institutionContacts()
->updateExistingPivot($contactId, ["type" => 1]);
Hope this helps.
I'm trying to figure out a way to combine data from two tables into a single variable that I can then send to my view. I'm using Authority as my authentication bundle and so I have the following tables set up: users, roles, role_user. I want to get the following data into a single variable.
From the users table:
id, name, email
From the roles table:
name
The following returns all the user data in the users table:
$users = User::all();
But, I want to make a chain that can get the related data stored in the roles table? I want all users and all of each users roles together.
And while I can find examples that help get related data for a single record I haven't been able to find any reference to retrieving entire tables with related data.
Thanks.
$users = User::with('roles')->get()
Eager loading is what you are looking for, read the docs :)
Im not 100% sure what you are after, I think you should make relations with Eloquents methods. But if you are looking for a way to just merge the data returned by two models you could do the following:
$users = User::all();
$roles = Roles::all();
$array = array_merge($users->toArray(), $roles->toArray());
return Response::json($array);
You could make the model calls so that they return exactly what you are after and then merge them together. If you want one Model to return something specific just make a function for it.
You need to use something like that:
$user = User::get();
$roles = Roles::get();
$user .= (object) $roles; //because of that both them are object array and we have to combine them as object array...
than you can pass the data to View
return View:make('templatefile')//or Redirect to_route whatever
->with('user', $user);
But the best way is belongs_to in your case. Please read the documentation:
http://laravel.com/docs/database/eloquent#relationships