I can't get my head around this:
$fragment = factory(Fragment::class)->create();
$this->assertCount(0, $fragment->values);
fragment->fetch(); // updates the 'values' by adding one Value object.
var_dump($fragment->id); // i.e. 6
var_dump(Fragment::first()->id); // 6
var_dump($fragment->values->count()); // 0
var_dump(Fragment::first()->values->count()); // 1
$this->assertCount(1, $fragment->values);
I use DatabaseTranscations, so after a Fragment is created, there is always one and only one. Thus, $fragment and Fragment::first() are the exact same instance. Yet... the values relationship is different. How can this be the case?
Note that this happens only during testing, when I manually test this through my controller (and the values are passed to the blade template page) it works just fine. I am confused :S.
Any ideas?
Relationship attributes ($fragment->values) are only loaded once. They are not kept up to date when you add or delete items from the relationship. They do not hit the database every time to check for changes.
Your second line is $this->assertCount(0, $fragment->values);. Accessing $fragment->values here lazy loads the relationship, and as your assert proves, it is empty.
You then call $fragment->fetch(), in which your comment says it adds a Value object to the fragment. However, your relationship attribute ($fragment->values) has already been loaded from the previous statement, so it will not reflect the additional Value object you added to the relationship.
Therefore, even after the call to fetch(), $fragment->values is still going to be an empty collection. Fragment::first()->values will contain the newly related Value though, because it is getting a new instance of the Fragment, and when it loads the values for the first time, it will pick up the related Value.
When you need to reload the relationship, you can use the load() method. If you add this after your call to fetch() (or put it in your fetch() method, whichever makes sense for you), your test will work fine.
$fragment = factory(Fragment::class)->create();
$this->assertCount(0, $fragment->values);
$fragment->fetch(); // updates the 'values' by adding one Value object.
var_dump($fragment->id); // i.e. 6
var_dump(Fragment::first()->id); // 6
var_dump($fragment->values->count()); // 0
// reload the values relationship
$fragment->load('values');
var_dump($fragment->values->count()); // 1
var_dump(Fragment::first()->values->count()); // 1
$this->assertCount(1, $fragment->values);
The other option you have is to use the relationship query by accessing the relationship method instead of the relationship attribute. If you do $fragment->values()->count() (note: values(), not values), that will hit the database every time and always return the current count.
Related
I'm new to laravel. I found a way here how to count article views, I used it on my own and it works as it should
$viewed = Session::get('viewed_article', []);
if (!in_array($article->id, $viewed)) {
$article->increment('views');
Session::push('viewed_article', $article->id);
}
But the only thing I do not fully understand is how it works and what it does, which makes me feel a little uneasy.
Who is not difficult, can you explain how this function works?
The first line:
$viewed = Session::get('viewed_article', []);
uses the Session facade to get the data with the key viewed_article from the session, or if nothing exists for that key, set $viewed to an empty array instead (the second argument sets the default value).
The next line, the if statement:
if (!in_array($article->id, $viewed)) {
makes sure that the current article id is not in the $viewed array.
If this condition is true (i.e. the article is not in the array), then the views are incremented (i.e. increased by one) on the article:
$article->increment('views');
Lastly, the article id is added into the viewed_article session data, so the next time the code runs, it won't count the view again:
Session::push('viewed_article', $article->id);
In my Laravel 5.1 app, I have classes Page (models a webpage) and Media (models an image). A Page contains a collection of Media objects and this relationship is maintained in a "media_page" pivot table. The pivot table has columns for page_id, media_id and sort_order.
A utility form on the site allows an Admin to manually associate one or more Media items to a Page and specify the order in which the Media items render in the view. When the form submits, the Controller receives a sorted list of media ids. The association is saved in the Controller store() and update() methods as follows:
[STORE] $page->media()->attach($mediaIds);
[UPDATE] $page->media()->sync($mediaIds);
This works fine but doesn't allow me to save the sort_order specified in the mediaIds request param. As such, Media items are always returned to the view in the order in which they appear in the database, regardless of how the Admin manually ordered them. I know how to attach extra data for the pivot table when saving a single record, but don't know how to do this (or if it's even possible) when passing an array to attach() or sync(), as shown above.
The only ways I can see to do it are:
loop over the array, calling attach() once for each entry and passing along the current counter index as sort_order.
first detach() all associations and then pass mediaIds array to attach() or sync(). A side benefit would be that it eliminates the need for a sort_order column at all.
I'm hoping there is an easier solution that requires fewer trips to the database. Or am I just overthinking it and, in reality, doing the loop myself is really no different than letting Laravel do it further down the line when it receives the array?
[SOLUTION] I got it working by reshaping the array as follows. It explodes the comma-delimited 'mediaIds' request param and loops over the resulting array, assigning each media id as the key in the $mediaIds array, setting the sort_order value equal to the key's position within the array.
$rawMediaIds = explode(',', request('mediaIds'));
foreach($rawMediaIds as $mediaId) {
$mediaIds[$mediaId] = ['sort_order' => array_search($mediaId, $rawMediaIds)];
}
And then sorted by sort_order when retrieving the Page's associated media:
public function media() {
return $this->belongsToMany(Media::class)->orderBy('sort_order', 'asc');
}
You can add data to the pivot table while attaching or syncing, like so:
$mediaIds = [
1 => ['sort_order' => 'order_for_1'],
3 => ['sort_order' => 'order_for_3']
];
//[STORE]
$page->media()->attach($mediaIds;
//[UPDATE]
$page->media()->sync($mediaIds);
I have some instances where a eloquent is resulting an single array not a collection. Although dd shows it as a collection with a single entry.
For example I have a query in a controller:
$pg = Page::with('getPanels')->where('slug',$slug)->get();
This will return a single result and works fine, so I pass this to a blade template. My complete function is
$pg = Page::with('getPanels')->where('slug',$slug)->get();
return view('front.page',['pg' => $pg]);
As soon as he template is brought in it will fall over at
if (!is_null($pg->headImage))
{$img = asset('images/pages')."/".$pg->headImage;}
and I will get
Property [headImage] does not exist on this collection instance.
If I change the line to
if (!is_null($pg[0]['headImage']))
it will continue OK. This is of course a pain as I would much rather use $pg->headImage.
Can someone enlighten me please?
I have sorted this and I hope it will help other people.
If I use
$pg = Page::with('getPanels')->where('slug',$slug)->first();
it will be just one result (naturally) and therefore
$pg->headImage
will fail as it wants
$pg[0]['headImage']
but if I change the eloquent instead of get(0 to first() (still just one result)
$pg = Page::with('getPanels')->where('slug',$slug)->first();
I can use $pg->headImage or what field I want.
I am trying to get the value of a single column using Eloquent:
MyModel::where('field', 'foo')->get(['id']); // returns [{"id":1}]
MyModel::where('field', 'foo')->select('id')->first() // returns {"id":1}
However, I am getting anything but the value 1. How can get that 1?
NOTE: It is possible that the record with field of foo does not exist in the table!
EDIT
I am ideally looking for a single statement that either returns the value (e.g. 1) or fails with a '' or null or other. To give you some more context, this is actually used in Validator::make in one of the rules:
'input' => 'exists:table,some_field,id,' . my_query_above...
EDIT 2
Using Adiasz's answer, I found that MyModel::where('field', 'foo')->value('id') does exactly what I need: returns an integer value or an empty string (when failed).
Laravel is intuitive framework... if you want value just call value() method.
MyModel::find(PK)->value('id');
MyModel::where('field', 'foo')->first()->value('id');
You're using the Eloquent query builder, so by default, it'll return an Eloquent model with only the value you wish.
The method you're looking for is pluck() which exists in the normal query builder (of which the Eloquent one extends) so your code should look as follows:
MyModel::where('field', 'foo')->pluck('id'); // returns [1]
The value() method that is being used in the other answers is an Eloquent model method. Using that means that the framework queries the database, hydrates the model and then returns only that value. You can save yourself a few keystrokes and few CPU cycles by using pluck() and have it handled simply in one query.
I am new to laravel and confused about some query methods.
find($id) is useful and returns a nice array, but sometimes I need to select by other fields rather than id.
The Laravel document said I could use where('field', '=', 'value') and return a bunch of data, which is fine.
What I can't understand is why I need to add ->first() every time, even if I am pretty sure there is only one single row matches the query.
It goes like this:
$query->where(..)->orderBy(..)->limit(..) etc.
// you can chain the methods as you like, and finally you need one of:
->get($columns); // returns Eloquent Collection of Models or array of stdObjects
->first($columns); // returns single row (Eloquent Model or stdClass)
->find($id); // returns single row (Eloquent Model or stdClass)
->find($ids); // returns Eloquent Collection
// those are examples, there are many more like firstOrFail, findMany etc, check the api
$columns is an array of fields to retrieve, default array('*')
$id is a single primary key value
$ids is an array of PKs, this works in find method only for Eloquent Builder
// or aggregate functions:
->count()
->avg()
->aggregate()
// just examples here too
So the method depends on what you want to retrieve (array/collection or single object)
Also the return objects depend on the builder you are using (Eloquent Builder or Query Builder):
User::get(); // Eloquent Colleciton
DB::table('users')->get(); // array of stdObjects
even if I am pretty sure there is only one single row matches the query.
Well Laravel cant read your mind - so you need to tell it what you want to do.
You can do either
User::where('field', '=', 'value')->get()
Which will return all objects that match that search. Sometimes it might be one, but sometimes it might be 2 or 3...
If you are sure there is only one (or you only want the first) you can do
User::where('field', '=', 'value')->first()
get() returns an array of objects (multiple rows)
while
first() returns a single object (a row)
You can of course use get() when you know it will return only one row, but you need to keep that in mind when addressing the result:
using get()
$rez = \DB::table('table')->where('sec_id','=','5')->get();
//will return one row in an array with one item, but will be addressed as:
$myfieldvalue = $rez[0]->fieldname;
using first()
$rez = \DB::table('table')->where('sec_id','=','5')->first();
// will also return one row but without the array, so
$myfieldvalue = $rez->fieldname;
So it depends on how you want to access the result of the query: as an object or as an array, and also depends on what "you know" the query will return.
first() is the equivalent of LIMIT 1 at the end of your SELECT statement. Even if your query would return multiple rows, if you use first() it will only return the first row