Eloquent relationship causes model nesting - sql

I have the Eloquent BfsImages model defined with the following relationship:
public function listing()
{
return $this->belongsTo('App\CommercialPeople\Models\BfsListings', 'bfs_listing_id', 'bfs_listing_id');
}
And the attribute appended:
public function getPathAttribute()
{
return config('settings.bfs_image_path') . $this->listing->auth_agent_id . '/' . $this->filename;
}
As you can see the attribute refers to the parent model, so when I call the following:
BfsListings::with('images')->all();
Even though technically the relationship from images to listings is not called, because of that reference in the custom attribute BfsListing model is appended to images which causes model nesting so I get BfsListing->BfsImages->BfsListing.
My question is, is there a way to refer to parent model without actually appending it and returning it's data? Or.. perhaps there is a better way to maybe pass a variable from the parent to the child so that it could be used without calling the relationship back again?
To be honest since all my models are cached I don't care that much about multiple queries back and forth, I just want to remove the unnecessary data from images model, however I could use some smart way around it to not duplicate the query.
Edit
its possible to refer to other models without using the relations like this:
$this->listing()->setEagerLoads([])->first()->auth_agent_id;
However this still means that the reference to the parent model will be made once, which again causes two level nesting (so basically problem is not solved, but in some cases this will help to avoid infinite loops).
I still can't figure out how to call the parent model without actually loading it again.

You can alias the parent -> child relationship then access the parent via the alias.
$a = $parent->child;
$b = $a->parent;

Related

Laravel 5: Can't get model property in relationship

I have a relationship in my model that requires a where condition:
public function characters() {
return $this->hasMany('Character')->where('characters.game_id', $this->game_id);
}
The problem is that "$this->game_id" doesn't appear to work. If I hard code the ID I need in its place, then the relationship works fine. I've also tried "$this->attributes['game_id']", which doesn't work either. I know that the value for "$this->game_id" exists, because I can view it when I return it in an accessor or as just a normal property in the resulting object. But for whatever reason, I can't access this value in the relationship. Thoughts?
Why do you require that particular where clause? I think hasMany does that for you.

Yii CActiveRecord with Column Named "attributes"

I used the CRUD generator from a legacy database. When searching for a column value I get the following error:
htmlspecialchars() expects parameter 1 to be string, array given (/usr/local/share/yii/framework/web/helpers/CHtml.php:103)
The problem is that the model has an existing column named "attributes" which is creating a conflict. I removed the entry from the _search.php and commented out all instances in the model hoping to at least get it working but no luck. Any suggestions would be appreciated.
Thanks.
Every CActiveRecord instance (or CModel instance for that matter) has a getter/setter named attributes with which all the attributes can be set. This leads to a conflict because the generated crud code uses the attributes attribute expecting it works as described before.
The controller does something like:
$model->attributes=$_POST['ModelClassName'];
// or
$model->attributes=$_GET['ModelClassName'];
This is meant to set al the (safe) attributes of the model at once. Instead this overwrites the database attribute attributes of your legacy DB model.
This in turn leads to the error you describe, because $_GET['ModelClassName'] and $_POST['ModelClassName'] typically contain arrays of data.
I guess the easiest fix would be to directly call the setter function for the "normal" attributes behavior which would lead to replacing the lines mentioned above with something like the following:
// in the controller
$model->setAttributes($_POST['ModelClassName']);
// and
$model->setAttributes($_GET['ModelClassName']);
I think rest of the generated CRUD code (the views) could and should be left untouched to make it work.
If you want to know how and why this works, it's best to do some research into the __get and __set magic functions and how they're used in the yii framework.

How to manually instantiate ActiveRecord truncated objects?

Working with ActiveRecord and JRuby, I try to invoke a stored procedure on a Database. Using the underlying Java Library I reached a point where I have a hash with the columns specified in the select.
Now I'd like to use this hash to have ActiveRecord models, but I'd like them to look like if I did a classic Model.select(columns).all (with only the columns values, errors when trying to reach the other ones and readonly).
There must be something inside of AR to do this but I can't find anything and all my search leads to all the basic "fetch" tutorials ...
OK so I kept digging in Rails code and figured out my answer was the instantiate method.
The idea is if you are inside a model called MyModel and do this
object = instantiate(value1: 1, value2: 'ok')
you will have an instance of the MyModel class with theses attributes defined. If the model is supposed to have more columns, they are not defined. The object is readonly.

NHibernate Component mapping (Creating Criteria)

Is there any way to create an “alias” for a component?
I have a “Criteria Builder” that takes strings in the format of “Address.City” (or “User.Address.City”, …) and creates an ICriteria (filters and sorts) based on it.
I am using components to map the “Address” class so it stays in the same table as “User”.
The exception I am getting is:
NHibernate.QueryExceptioncould not resolve property: City of: MyNamespace.User
If I attempt to do not create an “alias” for the Address Component, it works just fine.
However, as it is a criteria builder, is there a way to detect that “Address” is a component and avoid the call criteria.CreateAlias(“Address”)? Any work around?
This is the same question as mine, however the solution is not viable to me (I do not create criteria manually for each query).
Any help would be much appreciated!
You can't create an Alias for Address because Address is not a mapped entity. The only difference between CreateAlias and CreateCriteria is that the former returns the original Criteria, whereas the latter returns the new Subcriteria. So the only classes you can create Criteria for are classes that have been mapped. Since components are not mapped classes, you can't create a criteria around them.
The only suggestion I have is to have your Address class either to implement an empty descriptor interface like IComponent or mark it with a custom ComponentAttribute. Then your CriteriaBuilder can check whether or not the class it's creating a criteria for has this meta data and ignore it.

Using Criteria to get only base types

I'm looking for way in Fluent NHibernate to get a list of all object of type PARENT
using criteria.
I have a father object and a derived child.
The father contains a list of childs.
The problem is that when I use:
ICriteria crit = session.CreateCriteria(typeof(Parent))
IList<Parent> myRes = crit.List<Parnet>()
NH return back the list of both parent elements and the derived children elements, which is "right" b/c that is what I've asked, but that is not what I need.
(the children elements should be only inside the father object, but since they are of type parent as well - since they derived from it... NH brings them as well using this method.)
How can I get the list of all my "father" elements without the derived children ?
This is from the first answer (#Stefan Steinegger's)
session
.CreateQuery("from Parent where Parent.class == :class")
.AddType(typeof(Parent));
It looks like I need something like that - but it doesn't work in Fluent NHibernate.
Thanks,
Dani
the question actually is: how do you determine if a Parent is a root parent? there are various approaches:
You keep your model and define: a root is a Parent that is not inherited and is not included in any other Parent.
The part "is not inherited" might be easy to determine, but is actually a poor definition. When using inheritance, you should actually not care if an object you get as a certain type is actually inherited or not, this is the nature of inheritance.
The part "is not included in any other Parent" is hard to find out in an efficient way.
You set a reference to an objects parent. A root is a Parent where its parent references null.
You derive your Root from a common Base class. A Child is not a Root anymore, and a Root is a Root.
I suggest to take the last option.
BTW: you can filter for the exact type, but only using HQL.
session
.CreateQuery("from Parent where Parent.class == :class")
.AddType(typeof(Parent));