i have instance model from
$model = Model::find(1);
for example this instance always return these attribute (some is from $append):
-id
-name
-countRelation
-description
-created_at
-updated_at
what i want is to only retrive name and description from this instance;
makeVisible only work to show hidden attribute; i don't want use makeHidden because the result of find may change if on model i add new append attribute;
Since you are appending accessors limiting the SELECT statement won't stop those from being appended to the serializied output. You can use setVisible to do this though:
$model->setVisible(['name', 'description']);
Setting what is visible this way will limit the attributes, appends and relationships that are returned in the serialized output of the Model.
You can use select to only retrieve some column in your database, it will not affect append, see the doc for more info Eloquent
$model = Model::find(1);
// to this
$model = Model::select('name', 'description')->find(1);
See Query Builder for more insight about grabbing data from database.
if you retrieve name and description only, then you may use
$model = Model::select(['name', 'description'])->find(1);
You can use select() to select only certain columns in your query.
$model = Model::select('name', 'description')->find(1);
https://laravel.com/docs/8.x/queries#specifying-a-select-clause
You can also get the Model and use functions on the model. If you have a single Model you can use get().
$model = Model::find(1)->get('name', 'description');
If you have a collection you can use ->map->only(). This maps the only function as a callback for each Model in your Collection.
$models = $models->map->only(['name', 'description']);
Related
I started learning Laravel and I am trying to achieve the following:
Get data from database and display specific field.
Here is my code in the controller:
public function show()
{
$students = DB::select('select * from students', [1]);
return $students;
}
Here is my route code:
Route::get('', "StudentController#show");
That all works for me and I get the following displayed:
[{"id":1,"firstname":"StudentFirstName","lastname":"StudentLastName"}]
How can I get only the "lastname" field displayed?
Thanks in advance!
DB::select('select * from students')
is a raw query that returns an array of stdClass objects, meaning you have to loop through the array and access properties:
$students[0]->lastname
You can also use the query builder to return a collection of objects:
$collection = DB::table('students')->get();
$student = $collection->first();
$student->lastname;
Lastly, using the query builder, you can use pluck or value to get just the last name. If you only have one user, you can use value to just get the first value of a field:
DB::table('students')->where('id', 1)->value('lastname');
I strongly advise you to read the Database section of the Laravel docs.
$students[0]['lastname'] will return the last name field, the [0] will get the first student in the array.
I would recommend creating a model for Students, which would make your controller something like this:
$student = Students::first(); // to get first student
$student->lastname; // get last names
If you only want the one column returned, you can use pluck()
public function show()
{
$last_names= DB::table('students')->pluck('lastname');
return $last_names;
}
This will return an array of all the students' lastname values.
If you want just one, you can access it with $last_names[0]
As a side note, your show() method usually takes a parameter to identify which student you want to show. This would most likely be the student's id.
There are several ways you can accomplish this task. Firstly, I advise you to use the model of your table (probably Students, in your case).
Thus, for example,to view this in the controller itself, you can do something like this using dd helper:
$student = Students::find(1);
dd($student->lastname);
or, using pluck method
$students = Students::all()->pluck('lastname');
foreach($students as $lastName) {
echo $lastName;
}
or, using selects
$students = DB::table('students')->select('lastname');
dd($students);
Anyway, what I want to say is that there are several ways of doing this, you just need to clarify if you want to debug the controller, display on the blade...
I hope this helps, regards!
How to avoid querying relationship after object creation?
$store = new Store();
$store->name = 'Store 1';
$store->save();
return response()->json($store->products());
Laravel is querying products table. I would like to avoid that since I know there is none. This is just an example.
return response()->json([]); is not an option. In real world I really need to use $store->products().
Use the wasRecentlyCreated property of model to identify if the model was inserted during the current request lifecycle.
$data = $store->wasRecentlyCreated ? [] : $store->products();
Im getting various data out of my database.
Product::with('users');
I also have toe execute a complex raw query to get back some information. This is returned as an array.
In my method I would like to get products with users and then add on the data from my raw query to this collection, but this data comes back as an array. Something like:
Product::with('users');
Product->extraData = $rawQuery;
How can I add the raw query output to my Product Collection?
By using Eloquent Facade like Product:: you will get an Eloquent Model object as a result or an Eloquent Collection object as a result, including results retrieved via the get method or accessed via a relationship.
Now, if i understand correctly, you need to add a single extraData property to Eloquent Collection model alongside with Collection items? Or you need to add extraData for each Product ?
If you need to add additional property to Eloquent Collection object, maybe it is a good idea to use a Custom Collection. Please read this section: http://laravel.com/docs/5.1/eloquent-collections#custom-collections .
<?php namespace App;
use App\CollectionWithExtraData;
use Illuminate\Database\Eloquent\Model;
class User extends Model
{
public function newCollection(array $models = [])
{
return new CollectionWithExtraData($models);
}
}
And maybe your CollectionWithExtraData can have let's say a
public function setExtraData() {
}
or
public $extraData = array();
If you need extraData for each Product Eloquent Model, just create a new attribute within your Eloquent Model, make it public and set your extra data when needed. Make use of setExtraData() method and $extraData property from above
So I got the following code in my controller's show function which just returns a page with the tags:
$page = Post::with('tags')->findOrFail($id);
$page->tags->lists('name');
return response($page);
When I try to to execute this, it won't change the tags key, which is an array with the tags from the eloquent belongsToMany relationship.
Why isn't this working? To me it seems pretty handy to just change a value like this.
When I change it to $page->test = $page->tags->lists('name') it will add the test key as usual.
How would I modify a eloquent value in a easy way?
What works pretty well for such cases is overriding toArray in your Model:
public function toArray(){
$array = parent::toArray();
$array['tags'] = $this->tags->lists('name');
return $array;
}
After the $page = Post::with('tags')->findOrFail($id); line is executed, $page->tags is going to be an Illuminate\Database\Eloquent\Collection object containing all the related Tags for the Post. From your provided code and question, it sounds like you want to then change $page->tags to be an array containing just the related tag names.
The statement $page->tags->lists('name') is only going to return an array of all the names of the related tags; it does not modify the underlying collection. If you wanted to modify the $page->tags attribute, you would need to assign it the result of your statement:
$page->tags = $page->tags->lists('name');
However, $page->tags was an attribute that was dynamically created and assigned by the Model, and is expected to hold the contents of a relationship. Manually modifying the contents like this may have unintended consequences, but I do not know.
Edit
The Model::toArray() method merges in the relationship information over the attribute information. So, you can change the attribute, but if you echo the model, the relationship information will show up over your attribute change.
$page->tags = $page->tags->lists('name');
// this will echo the tags attribute, which is now the array of tags
echo print_r($page->tags, true);
// this will echo the model, with the tags attribute being
// overwritten with the related data
echo $page;
One option would be to unset the attribute (which also unsets the relationship) and then reassign the attribute to your desired data:
$page = Post::with('tags')->findOrFail($id);
$temp = $page->tags;
unset($page->tags); // you must unset the attribute before reassigning it
$page->tags = $temp->lists('name');
return response($page);
A little bit cleaner would be to use a different attribute name:
$page = Post::with('tags')->findOrFail($id);
$page->tagNames = $page->tags->lists('name');
unset($page->tags);
return response($page);
And another option is to do what #lukasgeiter suggested and override the Model::toArray method:
class Post extends Model {
public function toArray() {
// call the parent functionality first
$array = parent::toArray();
if (isset($this->tags)) {
$array['tags'] = $this->tags->lists('name');
}
return $array;
}
}
If you want to change the output of one of the relationships in the toArray/toJson methods, then use accessor:
// in order to not show the underlying collection:
protected $hidden = ['tags'];
// in order to append accessor to toArray output
protected $appends = ['allTags'];
// mutate the collection to be just an array of tag names
public function getAllTagsAttribute()
{
$collection = return $this->getRelation('tags');
return ($relation) ? $collection->lists('name') : [];
}
then you will get simple array instead of collection when you do $page->allTags or in the toArray/toJson output, while not showing the real collection.
It is allTags not `tags, since the latter should remain eloquent dynamic property, so you can work with it as usual before outputting anything.
not sure if this helps. To be honest, I do not get your point. But I guess there is something wrong with this line:
$page->tags->lists('name');
If $page->tags is a belongsToMany relationship and you want to add more query conditions after this relationship, you should query like this:
$page->tags()->lists('name');
I am looking for solution how to access eloquent model items by 'alias' field.
There is no problem accessing items by 'id'. But building a custom query I find myself unable to access item properties.
This piece of code works perfect
$cat = Category::find(1);
return $cat->title;
But if I am querying items with any other argument - properties are inaccessible
This code
$cat = Category::where('alias','=','vodosnab')->get();
return $cat->title;
throws an exception
Undefined property: Illuminate\Database\Eloquent\Collection::$title
Could you please help.
You already got the answer but here are some insights, when you use get() or all(), it returns a collection of model objects, which is an instance of Illuminate\Database\Eloquent\Collection, so here you'll get a Collection object
$cat = Category::where('alias','=','vodosnab')->get();
Now, you can use, $cat->first() to get the first item (Category Model) from the collection and you may also use $cat->last() to get the last item or $cat->get(1) to get the second item from the collection. These methods are available in the Collection object.
Using the first() method like Category::where('alias','=','vodosnab')->first(); will return you only a single (the first mathing item) model which is an instance of your Category model. So, use all() or get() to get a collection of model objects and you can loop through the collection like:
foreach(Category::all() as $cat) { // or Category::get()
$cat->propertyName;
}
Or you may use:
$categories = Category::where('alias','=','vodosnab')->get();
foreach($categories as $category) {
$category->propertyName;
}
Also, you may use:
$categories = Category::where('alias','=','vodosnab')->get();
$firstModel = $categories->first();
$lastModel = $categories->last();
$thirdModel = $categories->get(2); // 0 is first
If you need to get only one then you may directly use:
$category = Category::where('alias','=','vodosnab')->first();
$category->fieldname;
Remember that, if you use get() you'll get a collection of Model objects even if there is only one record available in the database. So, in your example here:
$cat = Category::where('alias','=','vodosnab')->get();
return $cat->title;
You are trying to get a property from the Collection object and if you want you may use:
$cat = Category::where('alias','=','vodosnab')->get();
return $cat->first()->title; // first item/Category model's title
return $cat->last()->title; // last item/Category model's title
return $cat->get(0)->title; // first item/Category model's title
You may read this article written on Laravel's Collection object.
get() returns a Collection of items. You probably need first() that returns a single item.