In a Symfony 2.8 controller, I get a field data with an association inverse side named owners.
At this point I have $form->get('foo')->getData()->getOwners()->getInitialized === false.
After that I perform some complex DQL query which can be simplified as :
"SELECT foo, owners
FROM Foo foo
LEFT JOIN foo.owners owners WITH IDENTITY(owners.bar) = 1
"
The important part is that there are several owners pointing on foo, but in the query we return only one of them, which makes subsequent calls to foo->getOwners() returning only one owner.
I see it as something dangerous because it means that accessing data via a DQL SELECT requests can actually makes you manipulate an association inverse side that is not synchronized with the database. I would not expect a SELECT request to do this kind of things.
Thanks
Related
I've got multiple entities set up with their respective repositories, all working properly. However, Doctrine seems to populate proxies where I don't want them to be populated.
I've got an entity called Item, which references a Category, both by having a $category_id and a $category field. The latter has the relationship set up with #ORM\ManyToOne() and #ORM\JoinColumn(), working correctly.
In my controller, when I'm querying Items, I receive a list of items with proxies to the related categories, which I can strip out from my response, identifying them as being proxies. However, if for whatever reason, I also query Categories in an unrelated query, the item-related query return with not proxies but actual hydrated Category instances, which I don't want.
$this->categoryRepository->findBy(...);
...
$items = $this->itemRepository->findBy(...);
return $this->respond($items);
Here, $items[0]->category will have been populated by the framework by the time the execution reaches the return statement.
Is it possible to turn this behaviour off?
You can specify the fetch policy on a relationship to be EXTRA_LAZY, this will fetch the least amount of date on execution as possible. Per the docs:
With Doctrine 2.1 a feature called Extra Lazy is introduced for associations. Associations are marked as Lazy by default, which means the whole collection object for an association is populated the first time its accessed.
So in your #ORM\ManyToOne() annotation, add a parameter: fetch="EXTRA_LAZY" to the others.
Iterations of this question have been asked in the past, but this presents unique challenges as it combines some of the issues in one larger problem.
I have an entity(User) that is used as the user class in my application, then I have another entity (UserExtra), in a one-to-one relationship with the user entity, UserExtra's id is the same as User. The foreign key is the same as the primary key.
When the user object is loaded (say by $this->getUser() or by {{ app.user }}, the UserExtra data is also loaded through a join. The whole point of having two entities is so I don't have to load all the data at once.
I even tried defining a custom UserLoaderInterface/UserProviderInterface Repository for User, making sure that refreshUser and loadUserByUsername would only load the User data (I'd like for the UserExtra data to sit in a proxy unless I explicitly need it) but when Doctrine goes to Hydrate the object, it issues an extra query to load the UserExtra data, thereby skipping the Proxy status.
Is there a way out of this?
there are many solution for your issue:
1) Change the owning side and inverse side http://developer.happyr.com/choose-owning-side-in-onetoone-relation - I don't think that's right from a DB design perspective every time.
2) In functions like find, findAll, etc, the inverse side in OneToOne is joined automatically (it's always like fetch EAGER). But in DQL, it's not working like fetch EAGER and that costs the additional queries. Possible solution is every time to join with the inverse entity
3) If an alternative result format (i.e. getArrayResult()) is sufficient for some use-cases, that could also avoid this problem.
4) Change inverse side to be OneToMany - just looks wrong, maybe could be a temporary workaround.
5) Force partial objects. No additional queries but also no lazy-loading: $query->setHint (Query::HINT_FORCE_PARTIAL_LOAD, true) - seams to me the only possible solution, but not without a price:
Partial Objects are a little bit risky, because your entity behavior is not normal. For example if you not specify in ->select() all associations that you will user you can have an error because your object will not be full, all not specifically selected associations will be null
6) Not mapping the inverse bi-directional OneToOne association and either use an explicit service or a more active record approach - https://github.com/doctrine/doctrine2/pull/970#issuecomment-38383961 - And it looks like Doctrine closed the issue
this question may help you : one to one relation load
I am new programmer student, now i develop mobile app with phonegap. So I use sqlite and persistence js.but I don't know how to write "inner join" in persistence js function. Hope all of you help me.
Take a look at documentation:
https://github.com/zefhemel/persistencejs
Some text from it:
The methods to define relationships to other entities:
EntityName.hasMany(property, Entity, inverseProperty)
defines a 1:N or N:M relationship (depending on the inverse property).
EntityName.hasOne(property, Entity)
defines a 1:1 or N:1 relationship.
If an object has a hasOne relationship to another which has not yet been fetched from the database (e.g. when prefetch wasn't used), you can fetch in manually using fetch. When the property object is retrieved the callback function is invoked with the result, the result is also cached in the entity object itself.
obj.fetch(prop, callback)
I need to create a fairly complex rule in Drupal - I am willing to use either code or the interface to do so.
I am more familiar with the interface, however, as opposed to the Rules API.
Anyway, the rule will be as follows:
It will happen based on a form submission from entityforms (which is one entity). It will take the checkbox value of a field (not just the true or false, but rather the value submitted when a value is true or false). It will convert this number to an integer.
At this point things get interesting - I want to create a new entity of registrations (a different entity), which as far as I can tell, means I'll have to bring a registration into scope. I also need to bring node (and not just node: type and other data selectors, but specifically node) into scope, because the next step requires it.
So at this point, I should have three entities loaded into scope:
entityforms
registration
node
I believe the best way to bring registration into scope would be entity is of type? The documentation page says that content of type should be appropriate - but that seems like it might be related to the specific use case of the example - not in my more complex example where registration isn't the first entity dealt with, but rather a second.
https://drupal.org/node/1463042
So anyway, if all three of these entities is called in correctly, the ultimate result should be the following:
Value from boolean field (not the straight 1 or 0, but whatever the value to be submitted is switched to) from the entityform is converted to an integer, and inserted where entity host ID is required. In the section where host entity type is the value should be node.
I am also open to alternative suggestions if this seems overly complex or poorly architected.
The Host Entity Type cannot be of Entityform? Why be a Node since a Registration can be attached to any entity? Then you will get the id of the Entityform as also as any other fields from that entity type instead of Node. Next steps are the same.
I'm having a problem updating a disconnected POCO model in an ASP.NET application.
Lets say we have the following model:
Users
Districts
Orders
A user can be responsible for 0 or more districts, an order belongs to a district and a user can be the owner of an order.
When the user logs in the user and the related districts are loaded. Later the user loads an order, and sets himself as the owner of the order. The user(and related districts) and order(and related district) are loaded in two different calls with two different dbcontexts. When I save the order after the user has assigned himself to it. I get an exception that saying that acceptchanges cannot continue because the object's key values conflict with another object.
Which is not strange, since the same district can appear both in the list of districts the user is responsible and on the order.
I've searched high and low for a solution to this problem, but the answers I have found seems to be either:
Don't load the related entities of one of the objects in my case that would be the districts of the user.
Don't assign the user to the order by using the objects, just set the foreign key id on the order object.
Use nHibernate since it apparently handles it.
I tried 1 and that works, but I feel this is wrong because I then either have to load the user without it's districts before relating it to the order, or do a shallow clone. This is fine for this simple case here, but the problem is that in my case district might appear several more times in the graph. Also it seems pointless since I have the objects so why not let me connected them and update the graph. The reason I need the entire graph for the order, is that I need to display all the information to the user. So since I got all the objects why should I need to either reload or shallow clone it to get this to work?
I tried using STE but I ran in to the same problem, since I cannot attach an object to a graph loaded by another context. So I am back at square 1.
I would assume that this is a common problem in anything but tutorial code. Yet, I cannot seem to find any good solution to this. Which makes me think that either I do not under any circumstance understand using POCOs/EF or I suck at using google to find an answer to this problem.
I've bought both of the "Programming Entity Framework" books from O'Reilly by Julia Lerman but cannot seem to find anything to solve my problem in those books either.
Is there anyone out there who can shed some light on how to handle graphs where some objects might be repeated and not necessarily loaded from the same context.
The reason why EF does not allow to have two entities with the same key being attached to a context is that EF cannot know which one is "valid". For example: You could have two District objects in your object graph, both with a key Id = 1, but the two have different Name property values. Which one represents the data that have to be saved to the database?
Now, you could say that it doesn't matter if both objects haven't changed, you just want to attach them to a context in state Unchanged, maybe to establish a relationship to another entity. It is true in this special case that duplicates might not be a problem. But I think, it is simply too complex to deal with all situations and different states the objects could have to decide if duplicate objects are causing ambiguities or not.
Anyway, EF implements a strict identity mapping between object reference identity and key property values and just doesn't allow to have more than one entity with a given key attached to a context.
I don't think there is a general solution for this kind of problem. I can only add a few more ideas in addition to the solutions in your question:
Attach the User to the context you are loading the order in:
context.Users.Attach(user); // attaches user AND user.Districts
var order = context.Orders.Include("Districts")
.Single(o => o.Id == someOrderId);
// because the user's Districts are attached, no District with the same key
// will be loaded again, EF will use the already attached Districts to
// populate the order.Districts collection, thus avoiding duplicate Districts
order.Owner = user;
context.SaveChanges();
// it should work without exception
Attach only the entities to the context you need in order to perform a special update:
using (var context = new MyContext())
{
var order = new Order { Id = order.Id };
context.Orders.Attach(order);
var user = new User { Id = user.Id };
context.Users.Attach(user);
order.Owner = user;
context.SaveChanges();
}
This would be enough to update the Owner relationship. You would not need the whole object graph for this procedure, you only need the correct primary key values of the entities the relationship has to be created for. It doesn't work that easy of course if you have more changes to save or don't know what exactly could have been changed.
Don't attach the object graph to the context at all. Instead load new entities from the database that represent the object graph currently stored in the database. Then update the loaded graph with your detached object graph and save the changes applied to the loaded (=attached) graph. An example of this procedure is shown here. It is safe and a very general pattern (but not generic) but it can be very complex for complex object graphs.
Traverse the object graph and replace the duplicate objects by a unique one, for example just the first one with type and key you have found. You could build a dictionary of unique objects that you lookup to replace the duplicates. An example is here.