I have a small (no, not that small) probleme in my current project. Today I came across with Yii and viaTable but something is not working with it. I think something is wrong with the table linking.
My goal would be to get all the data from the client windows(Ablak)
that is connected to a user via felhasznalo2ablak table.
I have 3 tables. Felhasznalo(Users in English), Ablak(Client Window in English) and Felhasznalo2Ablak which is the via table.
Here are the table structures:
Felhasznalo(Model):
public function getWindows() {
return $this->hasMany(Ablak::className(), ['id' => 'ablak_id'])- >viaTable('felhasznalo2ablak',['felhasznalo_id','id']);
}
Ablak(Model):
public function getUsers() {
return $this->hasMany(Felhasznalo::className(), ['id' => 'felhasznalo_id'])->viaTable('felhasznalo2ablak', ['ablak_id' => 'id']);
}
And the query in the controller:
$u = Felhasznalo::findOne(Yii::$app->user->getId());
$allowedWindows = $u->getWindows();
foreach ($allowedWindows as $aw) {
print_r($aw);
}
I want to get the ralational data from Ablak table that blongs to a specific user. It works but not tha way it should. Any ideas guys?
Thank you for your answers!
Gábor
Check the link in your Felhasznalo::getWindows()
public function getWindows() {
return $this
->hasMany(Ablak::className(), ['id' => 'ablak_id'])
->viaTable('felhasznalo2ablak', ['felhasznalo_id' => 'id']);
}
Query for all "Windows"
$u = Felhasznalo::findOne(Yii::$app->user->getId());
$allowedWindows = $u->getWindows()->all();
print_r($allowedWindows);
I forget to answer my thread. So the problem was solved by adding forign keys to my database structure and after that i generated the model files with gii.
Related
I am cleaning up a quite messy php laravel 8 project right now.
Currently my ressource looks like this:
class MyModelSimpleResource extends JsonResource
{
public function toArray($request)
{
return [
'id' => $this->id,
'name' => $this->name,
'my_calculated_attribute' => MyModel::whereRaw('fk_id = ? AND model_type = "xyz"', [$this->id])->count(),
];
}
}
My problem is that on calling the API endpoint, for every record of MyModel it creates a separate query to calculate my_calculated_attribute.
I know that you can define foreign key constrains in the model like and query like this:
MyModel::with('myFkModel')->get()
This works great for foreign keys. But how can I avoid n queries when I need this my_calculated_attribute.
Thanks a lot!
PS: I know that raw queries are a bad idea and I know that the resource is supposed to transform data and not query it. 😅
Ok, I figured it out. I don't only can define foreign keys in my model! I just defined a new relationship:
public function myFkModels(): HasMany
{
return $this->hasMany(MyFkModel::class);
}
public function myFkWithCondition(): HasMany
{
return $this->myFkModels()->where('model_type ', 'xyz');
}
This I can put in my with statement like this:
MyModel::with('myFkModels', 'myFkWithCondition')->get()
I'm just started to work with Laravel and think its a pretty good framework.
But there is a lot to learn and i can mostly find everything in the user guide except this part:
I'm trying to get items from my database they are sorted with a category id that relates to a other table item_catagories in this table are stored:
id
name
parent
In my url of the website I use the name of the category instead of the id.
http://example.com/catagory/subcatagory
when subcatagory has a value I want to search for the related items.
I now have it like this:
if($subcategory){
$foo = ItemCategories::where(['group' => $category, 'name'=> $subcategory])
->get()[0]->id;
$data['products'] = Items::where('category_id', $foo)->get();
}
but there must be a much simpler way to get the same results.
I hope someone can help me to understand how I can do it better
Edit
I forgot to add the relation code:
The item class:
public function categorie(){
return $this->hasOne('App\ItemCategories');
}
The categorie class:
public function items(){
return $this->belongsTo('App\Items');
}
You can use Laravel Eloquent's relationships for this. On your category model:
public function items() { return $this->hasMany('Items'); }
Once you've done that, on a category, you can do $category->items to fetch all of its related items.
Incidentally, when you do this:
->get()[0]
you can just do this:
->first()
If you wish to bring your results already populated, one way to do this is:
$foo = ItemCategories::where(['group' => $category, 'name'=> $subcategory])->with('items')->first();
I have three models: Person, Feature and PersonFeature. PersonFeature is a junction table with two foreign keys, person_id referencing id in the person table and feature_id referencing id in the feature table.
My question is does Gii in Yii2 generate all the relevant relations. These are the relation in each of the three models
Person:
public function getPersonfeatures()
{
return $this->hasMany(Personfeature::className(), ['personid' => 'id']);
}
Feature:
public function getPersonfeatures()
{
return $this->hasMany(Personfeature::className(), ['featureid' => 'id']);
}
PersonFeature:
public function getPerson()
{
return $this->hasOne(Person::className(), ['id' => 'personid']);
}
public function getFeature()
{
return $this->hasOne(Feature::className(), ['id' => 'featureid']);
}
But when I browse other posts I see that there exists a 'viaTable' operation for example:
public function getPerson() {
return $this->hasMany(Person::className(), ['id' => 'personid'])
->viaTable('personfeature', ['featureid' => 'id']);}
So basically my question is, is Yii supposed to generate this for me? Or can I manually add it in?
Cheers
The last function (with viaTable) is a many to many relationship, that function can be used just as any other relational function (for instance in a ->with() query).
You don't need a model for your join table, unless you want to use it for something else.
Hope this helps.
I'm trying to get data from a join table in Yii2 without an additional query. I have 2 models (User, Group) associated via the junction table (user_group). In the user_group table, I want to store extra data (admin flag, ...) for this relation.
What's the best way to add data to the junction table? The link method accepts a parameter extraColumns but I can't figure out how this works.
What's the best way to retrieve this data? I wrote an additional query to get the values out of the junction table. There must be a cleaner way to do this?!
FYI, this is how I defined the relation in the models:
Group.php
public function getUsers() {
return $this->hasMany(User::className(), ['id' => 'user_id'])
->viaTable('user_group', ['group_id' => 'id']);
}
User.php
public function getGroups() {
return $this->hasMany(Group::className(), ['id' => 'group_id'])
->viaTable('user_group', ['user_id' => 'id']);
}
In short: Using an ActiveRecord for the junction table like you suggested is IMHO the right way because you can set up via() to use that existing ActiveRecord. This allows you to use Yii's link() method to create items in the junction table while adding data (like your admin flag) at the same time.
The official Yii Guide 2.0 states two ways of using a junction table: using viaTable() and using via() (see here). While the former expects the name of the junction table as parameter the latter expects a relation name as parameter.
If you need access to the data inside the junction table I would use an ActiveRecord for the junction table as you suggested and use via():
class User extends ActiveRecord
{
public function getUserGroups() {
// one-to-many
return $this->hasMany(UserGroup::className(), ['user_id' => 'id']);
}
}
class Group extends ActiveRecord
{
public function getUserGroups() {
// one-to-many
return $this->hasMany(UserGroup::className(), ['group_id' => 'id']);
}
public function getUsers()
{
// many-to-many: uses userGroups relation above which uses an ActiveRecord class
return $this->hasMany(User::className(), ['id' => 'user_id'])
->via('userGroups');
}
}
class UserGroup extends ActiveRecord
{
public function getUser() {
// one-to-one
return $this->hasOne(User::className(), ['id' => 'user_id']);
}
public function getGroup() {
// one-to-one
return $this->hasOne(Group::className(), ['id' => 'userh_id']);
}
}
This way you can get the data of the junction table without additional queries using the userGroups relation (like with any other one-to-many relation):
$group = Group::find()->where(['id' => $id])->with('userGroups.user')->one();
// --> 3 queries: find group, find user_group, find user
// $group->userGroups contains data of the junction table, for example:
$isAdmin = $group->userGroups[0]->adminFlag
// and the user is also fetched:
$userName = $group->userGroups[0]->user->name
This all can be done using the hasMany relation. So you may ask why you should declare the many-to-many relation using via(): Because you can use Yii's link() method to create items in the junction table:
$userGroup = new UserGroup();
// load data from form into $userGroup and validate
if ($userGroup->load(Yii::$app->request->post()) && $userGroup->validate()) {
// all data in $userGroup is valid
// --> create item in junction table incl. additional data
$group->link('users', $user, $userGroup->getDirtyAttributes())
}
I don't know for sure it is best solution. But for my project it will be good for now :)
1) Left join
Add new class attribute in User model public $flag;.
Append two lines to your basic relation but don't remove viaTable this can (and should) stay.
public function getUsers()
{
return $this->hasMany(User::className(), ['id' => 'user_id'])
->viaTable('user_group', ['group_id' => 'id'])
->leftJoin('user_group', '{{user}}.id=user_id')
->select('{{user}}.*, flag') //or all ->select('*');
}
leftJoin makes possible to select data from junction table and with select to customize your return columns.
Remember that viaTable must stay because link() relies on it.
2) sub-select query
Add new class attribute in User model public $flag;
And in Group model modified getUsers() relation:
public function getUsers()
{
return $this->hasMany(User::className(), ['id' => 'user_id'])
->viaTable('user_group', ['group_id' => 'id'])
->select('*, (SELECT flag FROM user_group WHERE group_id='.$this->id.' AND user_id=user.id LIMIT 1) as flag');
}
As you can see i added sub-select for default select list. This select is for users not group model. Yes, i agree this is litle bit ugly but does the job.
3) Condition relations
Different option is to create one more relation for admins only:
// Select all users
public function getUsers() { .. }
// Select only admins (users with specific flag )
public function getAdmins()
{
return $this->hasMany(User::className(), ['id' => 'user_id'])
->viaTable('user_group', ['group_id' => 'id'],
function($q){
return $q->andWhere([ 'flag' => 'ADMIN' ]);
});
}
$Group->admins - get users with specific admin flag. But this solution doesn't add attribute $flag. You need to know when you select only admins and when all users. Downside: you need to create separate relation for every flag value.
Your solution with using separate model UserGroup still is more flexible and universal for all cases. Like you can add validation and basic ActiveRecord stuff. These solutions are more one way direction - to get stuff out.
Since I have received no answer for almost 14 days, I'll post how I solved this problem. This is not exactly what I had in mind but it works, that's enough for now. So... this is what I did:
Added a model UserGroup for the junction table
Added a relation to Group
public function getUserGroups()
{
return $this->hasMany(UserGroup::className(), ['user_id' => 'id']);
}
Joined UserGroup in my search model function
$query = Group::find()->where('id =' . $id)->with('users')->with('userGroups');
This get's me what I wanted, the Group with all Users and, represented by my new model UserGroup, the data from the junction table.
I thought about extending the query building Yii2 function first - this might be a better way to solve this. But since I don't know Yii2 very well yet, I decided not to do for now.
Please let me know if you have a better solution.
For that purpose I've created a simple extension, that allows to attach columns in junction table to child model in relation as properties.
So after setting up this extension you will be able to access junction table attributes like
foreach ($parentModel->relatedModels as $childModel)
{
$childModel->junction_table_column1;
$childModel->junction_table_column2;
....
}
For more info please have look at
Yii2 junction table attributes extension
Thanks.
UPDATE: Apparently $problem->userRatings()->count(); returns 1, so a record does exist, but the script still doesn't enter the foreach loop for some reason...
UPDATE 2/Solution: I feel incredibly foolish, but the reason it isn't working, is that I was calling foreach($problem->userRatings() as $rating){ when it should be foreach($problem->userRatings as $rating){ (dynamic property)
In my database I have problem_ratings, problems, and users. I have models for users and problems, and problems_ratings is a pivot table between problems and users with an extra 'content' column that stores the numeric rating value (1-5).
The many-to-many relation in my Problem model:
public function userRatings(){
return $this->belongsToMany('User', 'problem_ratings', 'author_id', 'problem_id')->withPivot('content');
}
The many-to-many relation in my User model:
public function problemRatings(){
return $this->belongsToMany('Problem', 'problem_ratings', 'author_id', 'problem_id')->withPivot('content');
}
When creating a problem_ratings element, I attach it to my user model like so:
$user->problemRatings()->attach($problem->id, array('content' => $val));
I can access the pivot table through the user, but when I try this:
foreach($problem->userRatings() as $rating){
echo "In average loop";
$newAverage = ($rating->pivot->content) + $newAverage;
}
it doesn't find any records, even though some exist in the database. Am I using these relations correctly?
Thanks in advance!
In the Problem model I think your relationship should looks something like :
public function userRatings(){
return $this->belongsToMany('User', 'problem_ratings', 'problem_id', 'author_id')->withPivot('content');
}
When using a foreach loop over something like this, you need to use dynamic properties (ie. without parentheses):
foreach($problem->userRatings as $rating){ instead of foreach($problem->userRatings() as $rating){