I have cases, cases_judges, judges and witness tables.
A case can have many judges and witness
I want to be able to select all the judges and witness associated to a case
I don't know how to create a relationship between case and judges because their is no direct link between judges and case. Cases_judges is the only intermediary between case and judge. I also tried using Hasmanythrough relationship but without success
Cases model
public function case_judges(){
return $this->hasMany(Cases_judges::class,'case_id','id');
}
public function witness(){
return $this->hasMany(Witness::class,'case_id','id');
}
public function judges(){
return $this->hasManyThrough(Judges::class, Case_judge::class,'judge_id','id');
}
Judges model
public function judges(){
return $this->hasMany(Case_judge::class,'case_id','id');
}
Cases_judge model
public function case(){
return $this->belongsTo(Cases::class);
}
Cases Controller
My case controller is something like this
public function index()
{
return Cases::with('case_judge','witness')->get();
}
This fiddle (http://sqlfiddle.com/#!9/217dcb/2/0)shows how I would have done it using raw query but I want to do it the eloquent way
To arrive at the solution, first we have to uncover what really is the relationship between your Case and Judge models.
The simplified diagram highlights the connection between your Case and Judge models via an intermediate CaseJudge model. Indeed, a Case really can have multiple Judges. However, we must not miss out the fact that a Judge can handle multiple Cases.
From this, we can conclude that Case and Judge models have a many-to-many relationship.
To establish a many-to-many relationship between models in Laravel, you must use belongsToMany relationship method, as opposed to hasManyThrough which only applies to one-to-many relationship.
class Cases extends Model {
...
public function judges() {
return $this->belongsToMany(Judges::class, 'case_judges', 'case_id', 'judge_id');
}
}
Here, belongsToMany has four arguments:
Model that has the many-to-many relationship with our Cases model.
Intermediate table connecting tables cases and judges.
Foregin key on intermediate table that connects to table cases.
Foregin key on intermediate table that connects to table judges.
When all is set and done, running:
return Cases::with(['judges', 'witness'])->get();
will now return what you want — a collection of cases, along with witnesses and judges associated to their respective cases.
As a side note: you might want to follow Laravel's conventions on naming things, to avoid running into weird default Eloquent behaviors as consequence, and enjoy any conveniences it brings when you conform to these conventions.
I think cases and judges are 'Many to Many' relationship with intermediate table cases_judges.
You can follow this document to setup this : https://laravel.com/docs/9.x/eloquent-relationships#many-to-many
Related
In my app, you can create lists of roles that are attached to contacts. So you can assign the contact "Bob" the roles of "Gardener" and "Pet Sitter". Then you can create the list "People" and add "Gardener (Bob)" and "Pet Sitter (Bob)" to it.
I have the following tables:
contacts
id
name
roles
id
name
contact_role (pivot)
id
contact_id
role_id
lists
id
name
contact_role_list (pivot)
id
contact_role_id
list_id
Everything was working smoothly until the second pivot table linked to the first pivot table. My pivot tables are (currently) not having any models so I'm not sure if there is a built-in feature to tackle this in Laravel or if I need to think differently.
I currently have this in my List model:
public function list_roles(): BelongsToMany
{
return $this->belongsToMany(XYZ::class, 'contact_role_list', 'list_id', 'contact_role_id');
}
Is this even close? What do I put where it says XYZ::class?
Ok, so the below is doing what I want, but is there an even better way to do it? The key to solving my problem was to create a Model for ContactRole and changing extends Model to extends Pivot.
I placed this in my List Model:
public function list_roles(): BelongsToMany
{
return $this->belongsToMany(ContactRole::class, 'contact_role_list', 'list_id', 'contact_role_id');
}
And this in my ContactRole Model:
public function contact(): BelongsTo
{
return $this->belongsTo(Contact::class);
}
Now I could reach the contact data by using something like this: List::first()->contact_roles->first()->contact
Any way to use with, pivot or similar to tidy this up even more? Thanks!
I like to approach these issues in terms of Models rather than pivots. I think many new Developers in Laravel get over obsessed with what's going on in the Database which is fine, but theres a lot of Magic going on so you can write very simple code that does a lot of Heavy lifting, so that being said if I fully understand your problem
You have a Contacts Model
This model can have many roles
so in your contacts Model you need a role relationship
public function roles()
{
return $this->belongsToMany(Roles::class);
}
next of course you have a role Model (pun intended)
your each role can have many list
public function lists()
{
return $this->hasMany(List::class)
}
then the idea is now that you have roles on contacts and lists on roles you should be able to have many lists through contact
public function lists()
{
return $this->hasManyThrough(List::class, Role::class);
}
I've done similar things before and for your description it seems like that's the approach you might need to take.
I have a problem with Laravel relationships.
I need to make relationship based on this table:
issuer and friend need to be united. Relationship will return all rows where user id in issuer or in friend. At the moment code looks like this:
return DB::table('contacts')->select()->where('friend', $this->id)->orWhere('issuer', $this->id)->where('status', 'approved');
Previously I used that method, but there are no relationship, 'cause attach() is undefined.
private function contactsIssued() {
return $this->belongsToMany(User::class, 'contacts','issuer', 'friend');
}
private function contactsFriended() {
return $this->belongsToMany(User::class, 'contacts','friend', 'issuer');
}
public function contacts() {
return $this->contactsIssued()->union($this->contactsFriended()->toBase());
}
So, I need to make one relationship that has two foreign columns.
Sorry, my English can be broken, 'cause it's not my native language.
That's look like a one to many relationship but you are using belongsToMany which is many to many relationship and required a pivot table.
if you have user model that has many contact model then in your contact model you should use the one to many relationship by using belongsTo.
but if you have 3 table you didn't say that in you question then please edit you question and provide your models and the relations between them.
I'm building a DB for a software where authentication is coupled with the companys LDAP Server.
I now have the two tables
AD_Groups
and
AD_Users
Which are joined in the table
AD_UsersXAD_Groups
I already learnt about establishing relationships in eloquent.
The many to many relationship is exemplified in the official docs by this:
https://laravel.com/docs/5.8/eloquent-relationships#many-to-many
Now, as you can see, the following feature of eloquent won't help me much:
"To define this relationship, three database tables are needed: users, roles, and role_user. The role_user table is derived from the alphabetical order of the related model names, and contains the user_id and role_id columns."
I therefore need to override this derived name by using the second parameter, as described here:
"As mentioned previously, to determine the table name of the relationship's joining table, Eloquent will join the two related model names in alphabetical order. However, you are free to override this convention. You may do so by passing a second argument to the belongsToMany method:
return $this->belongsToMany('App\Role', 'role_user');
But as seen in the above example from the docs, the infamous "snake case" is still applied to the name.
However, I'm affraid this might not work for my case.
Admittedly, AD_UsersXAD_Groups is pretty ugly, and I fear that eloquent/lumen will not be able to correctly identify its elements and apply the snake case rule correctly.
But I don't know for sure, and therefore I'm asking you what will be the most likely to work.
Using AD_UsersXAD_Groups or AD_UserXAD_Group
Because you have an "x", the Eloquent magic will never be able to match your table automatically.
You can override the table name in the relationship in your User model. You can also specify the keys if they are not Eloquent's expected "group_id" and "user_id":
function groups() {
return $this->belongsToMany(GroupModel::class, 'AD_UsersXAD_Groups', 'user_id_key', 'group_id_key')
}
And in your Group model you could do this to reverse it
function users() {
return $this->belongsToMany(UserModel::class, 'AD_UsersXAD_Groups', 'group_id_key', 'user_id_key')
}
I have a couple of models that I have included pivot tables for to avoid a polymorphic relation.
role table
id
name
description
restriction table
id
rule
status
restriction_role table
id
restriction_id
role_id
Reason for this setup is that both Roles and Restrictions can actually belong to multiple other models. In this case, a Role can only have 1 Restriction. I would normally define this as
class Role extends Eloquent {
public function restrictions()
{
return $this->hasOne('Restriction');
}
}
This obviously does not work because Laravel is unaware of the pivot table connecting this relation. I could easily accomplish this by using a many-to-many relationship instead, but this is not exactly how my model works. Not seeing anything in the documentation for defining this. Any thoughts?
I've solved this by using the belongsToMany relation and defining a custom accessor for it, like so:
public function foo()
{
return $this->belongsToMany(App\Bar::class);
}
public function getFooAttribute()
{
return $this->foo()->first();
}
As #deczo stated in the comments, belongsToMany() is about all that will work here. I recommend returning the first result using the first() method if you require only one result but cannot use a hasOne() relationship.
I've been working with PHP for years but have never really ventured out of procedural programming except when working with things like IPB and Magento. I'm trying to advance to the next level and get a better understanding of application structures, OOP, and some common PHP frameworks. That being said, I apologize if my question sounds immature or technically incorrect, I'm new to all of this.
Anyway, I was thinking about the structure of a simple forum. Forgetting about categories, tags, users, roles, advanced editors/bbcode, etc for now and just focusing on the topics and posts...
Because a topic is essentially a series of linked posts ordered by their created_at column, is there a necessity for an actual topics table or could one not simply have a parent column in the posts table? Topics would be identified as posts with a parent equal to their own id, null or 0; something that would otherwise be unused.
If that were the db schema, how would it be laid out in the code, and if relevant, Laravel? Could you still create a Topic model? What would be the pros and cons to having two models working from a single table?
Lastly, how would you approach it if you were creating it? Would you use two tables? A pivot table? Something else? Please explain why you would implement it that way.
For the database design, self referencing tables are a valid design pattern and useful in cases of nested hierarchies such as Categories that can contain sub-categories that can also contain sub-categories ect ect... In this case sub-categories are categories that have a parent but there is no other distinction between them.
It's up to you to decide if a Topic and Post is an identical entity with a parent-child relationship. Personally the way I define the objects I don't feel they are.
The topic-post relationship you're describing is probably more of a One to Many relationship with the topic being the owner or maybe even a Many to Many relationship. This depends on the answer to, "can your topic have many posts? Can your posts be part of many topics?"
If you answered yes and no, then it is a One to Many with topics being the parent aka owner in the relationship.
If you answered yes and yes, then you have a Many to Many relationship. In SQL these are represented by a table with two columns that reference id's from two tables.
If you answered no and yes, then you have a One to Many with posts being the parent aka owner in the relationship.
In laravel, depending on the relationship, your models would include a method that looks like this:
One to Many:
class Topic extends Eloquent
{
public function posts()
{
return $this->hasMany('Post');
}
}
Laravel One-to-Many Relationships
Many to Many:
In laravel the term "pivot table" refers to the table with references to the other objects.
class Post extends Eloquent
{
public function topics()
{
return $this->belongsToMany('Topic');
}
}
class Topic extends Eloquent
{
public function posts()
{
return $this->belongsToMany('Post');
}
}
Laravel Many-to-Many
Self referencing model:
For a self referencing parent child relationship like I explained before you could create something like this, as you can see it's just a one-to-many and the many-to-one in the same model.
class Category extends Eloquent
{
public function parent()
{
return $this->belongsTo('Category', 'parent_id');
}
public function children()
{
return $this->hasMany('Category', 'parent_id');
}
}
There is also the Polymorphic Relation.
This is useful when you have the same entity with just a different type. For example in this table you can have an insurance policy for an employee and a manager. The personType column in the insurancePolicies table defines who the insurance policy belongs to.
Image from codecommit.com
Our laravel models in this case would look like:
class InsurancePolicy extends Eloquent
{
public function insurable()
{
return $this->morphTo();
}
}
class Manager extends Eloquent
{
public function insurance()
{
return $this->morphMany('InsurancePolicy', 'person');
}
}
class Employee extends Eloquent
{
public function insurance()
{
return $this->morphMany('InsurancePolicy', 'person');
}
}
Most everything of what I've explained can also be found in the laravel docs