I have a working Core Data app and I want to display a representation for some of the Entities. I have set up an NSCollectionView with the Interface Builder "Core Data Entity Assistant" to setup the collection (generated a View in the MyDocument.xib), and can access simple representedObject.attributes, as well as simple relationship attributes.
my problem is with the to-many Relationships, which I would like to display as tables nested in the Collection item. I have tried different representedObject keypath combinations for the NSTableColumns, but did not figure out the correct cocoa binding incantation to drill down the data.
EntityA (reprensented in the Collection) <WORKS>
. EntityB (simple relationship) <WORKS with representedObject.relationship.attr>
.. EntityC (to-many-relationsip of EntityB) <how to get there???>
as of right now 99% of the code is generated through the Core Data Model and by Interface Builder. I am not opposed to subclassing something to get the desired behavior but I would prefer to keep things as automated as possible -- especially since this should "just work" with the as-is classes. using Xcode 3.2.5 -- I don't mind jumping to 4GM if someone tells me the bindings are more explicit there.
Related
I have a 'document' table (very original) that I need to dynamically subset at runtime so that my API consumers can't see data that isn't legal to view given some temporal constraints between the application/database. JOOQ created me a nice auto-gen Document class that represents this table.
Ideally, I'd like to create an anonymous subclass of Document that actually translates to
SELECT document.* FROM document, other_table
WHERE document.id = other_table.doc_id AND other_table.foo = 'bar'
Note that bar is dynamic at runtime hence the desire to extend it anonymously. I can extend the Document class anonymously and everything looks great to my API consumers, but I can't figure out how to actually restrict the data. accept() is final and toSQL doesn't seem to have any effect.
If this isn't possible and I need to extend CustomTable, what method do I override to provide my custom SQL? The JOOQ docs say to override accept(), but that method is marked final in TableImpl, which CustomTable extends from. This is on JOOQ 3.5.3.
Thanks,
Kyle
UPDATE
I built 3.5.4 from source after removing the "final" modifier on TableImpl.accept() and was able to do exactly what I wanted. Given that the docs imply I should be able to override accept perhaps it's just a simple matter of an erroneous final declaration.
Maybe you can implement one of the interfaces
TableLike (and delegate all methods to a JOOQ implementation instance) such as TableImpl (dynamic field using a HashMap to store the Fields?)
Implement the Field interface (and make it dynamic)
Anyway you will need to remind that there are different phases while JOOQ builds the query, binds values, executes it etc. You should probably avoid changing the "foo" Field when starting to build a query.
It's been a while since I worked with JOOQ. My team ended up building a customized JOOQ. Another (dirty) trick to hook into the JOOQ library was to use the same packages, as the protected identifier makes everything visible within the same package as well as to sub classes...
I am having a very hard time understanding what needs to be included in the Children Views in order to perform a fetch request and display the results in a table view when using Core Data. All the examples I have found are either only one layer deep (Random Dates), using the Root View Controller which always works, or using several view controllers with pictures and other attributes (Recipes) that make it confusing for me to follow.
An example of what I am looking for would be an Entity with three attributes. The entity is album and the three attributes are albumTitle, albumArtist and yearRecorded.
Now in my Navigation app my Root View Controller has three rows to choose from not using the Entity or Core Data at all. The three choices are "Title", "Artist" and "Year". When you click on one of the three rows it will push a new view controller and list all of the appropriate attributes in a new table view.
I believe it should be very simple and not require too much code but I can't get a handle on it. Any explanations or sample code is greatly appreciated.
You could just make a fetch request with no predicates to get all the objects from your Core Data store, so, you'll have an array of songs.
Than you just call, for example, [fetchedSongs valueForKeyPath:#"artist"]; to get an arry of artist and add it as a source to your tableview.
I want to serialize an Entity Framework Self-Tracking Entities full object graph (parent + children in one to many relationships) into Json.
For serializing I use ServiceStack.JsonSerializer.
This is how my database looks like (for simplicity, I dropped all irrelevant fields):
I fetch a full profile graph in this way:
public Profile GetUserProfile(Guid userID)
{
using (var db = new AcmeEntities())
{
return db.Profiles.Include("ProfileImages").Single(p => p.UserId == userId);
}
}
The problem is that attempting to serialize it:
Profile profile = GetUserProfile(userId);
ServiceStack.JsonSerializer.SerializeToString(profile);
produces a StackOverflowException.
I believe that this is because EF provides an infinite model that screws the serializer up. That is, I can techincally call: profile.ProfileImages[0].Profile.ProfileImages[0].Profile ... and so on.
How can I "flatten" my EF object graph or otherwise prevent ServiceStack.JsonSerializer from running into stack overflow situation?
Note: I don't want to project my object into an anonymous type (like these suggestions) because that would introduce a very long and hard-to-maintain fragment of code).
You have conflicting concerns, the EF model is optimized for storing your data model in an RDBMS, and not for serialization - which is what role having separate DTOs would play. Otherwise your clients will be binded to your Database where every change on your data model has the potential to break your existing service clients.
With that said, the right thing to do would be to maintain separate DTOs that you map to which defines the desired shape (aka wireformat) that you want the models to look like from the outside world.
ServiceStack.Common includes built-in mapping functions (i.e. TranslateTo/PopulateFrom) that simplifies mapping entities to DTOs and vice-versa. Here's an example showing this:
https://groups.google.com/d/msg/servicestack/BF-egdVm3M8/0DXLIeDoVJEJ
The alternative is to decorate the fields you want to serialize on your Data Model with [DataContract] / [DataMember] fields. Any properties not attributed with [DataMember] wont be serialized - so you would use this to hide the cyclical references which are causing the StackOverflowException.
For the sake of my fellow StackOverflowers that get into this question, I'll explain what I eventually did:
In the case I described, you have to use the standard .NET serializer (rather than ServiceStack's): System.Web.Script.Serialization.JavaScriptSerializer. The reason is that you can decorate navigation properties you don't want the serializer to handle in a [ScriptIgnore] attribute.
By the way, you can still use ServiceStack.JsonSerializer for deserializing - it's faster than .NET's and you don't have the StackOverflowException issues I asked this question about.
The other problem is how to get the Self-Tracking Entities to decorate relevant navigation properties with [ScriptIgnore].
Explanation: Without [ScriptIgnore], serializing (using .NET Javascript serializer) will also raise an exception, about circular
references (similar to the issue that raises StackOverflowException in
ServiceStack). We need to eliminate the circularity, and this is done
using [ScriptIgnore].
So I edited the .TT file that came with ADO.NET Self-Tracking Entity Generator Template and set it to contain [ScriptIgnore] in relevant places (if someone will want the code diff, write me a comment). Some say that it's a bad practice to edit these "external", not-meant-to-be-edited files, but heck - it solves the problem, and it's the only way that doesn't force me to re-architect my whole application (use POCOs instead of STEs, use DTOs for everything etc.)
#mythz: I don't absolutely agree with your argue about using DTOs - see me comments to your answer. I really appreciate your enormous efforts building ServiceStack (all of the modules!) and making it free to use and open-source. I just encourage you to either respect [ScriptIgnore] attribute in your text serializers or come up with an attribute of yours. Else, even if one actually can use DTOs, they can't add navigation properties from a child object back to a parent one because they'll get a StackOverflowException.
I do mark your answer as "accepted" because after all, it helped me finding my way in this issue.
Be sure to Detach entity from ObjectContext before Serializing it.
I also used Newton JsonSerializer.
JsonConvert.SerializeObject(EntityObject, Formatting.Indented, new JsonSerializerSettings { PreserveReferencesHandling = PreserveReferencesHandling.Objects });
Has anyone been able to use a SubSonic generated collection as a "business object datasource" with Microsoft report (rdlc)? I have generated the SubSonic class code but for some reason the report datasource window is not seeing the class as a potential object collection datasource.
Is there something I need to do for this to work?
Thanks in advance...vsdotnetguy
I have loaded Reporting Service reports from business objects before (loaded via NHibernate -- which isn't exact but close enough for argument sake).
Couple of key points:
1. return your objects in List, even if you are only returning one object.
2. You want FLAT business objects. You might have to go thru a DTO transformation to get that. By flat, I mean the most complex property you can have in a business object is a string and a number (int, decimal, double). If you are expecting to grab a value like this:
myObject.Customer.Name, forget it. Create a CustomerName property.
3. If you need data from multiple places try to break up your reports into subreports. You key off of the datasource key to figure out what data to return to the report.
I'll add more as I remember, it has been a few months since I've done this.
Yes I've done it, you should only need to make sure the project containing your reports references your SubSonic project (obviously :).
Sometimes I've also found that Visual Studio can get a little borked and require a restart before repopulating the datasource window with SubSonic generated objects.
Thx Chris and Adam,
Here is the answer I found.
In my case I wanted to dynamically set the main and subreport datasources at run time using the SubSonic object collections. However, I also wanted to design the report layout using drag and drop of the datasource columns.
But I was unable to design the report using drag&drop because none of my SubSonic collections were showing up in the Website Data Sources.
However, later while I was doing some control binding using the ObjectDataSource control, I noticed that NOW my SubSonic collections were showing up in the Website DataSources window and I could drag and drop the report layout.
So if you are dynamically setting the report datasources at run time and ARE NOT using the ObjectDataSource control already in your project, you MUST add a dummy ObjectDataSource control to one of your aspx pages. This will then make the business object datasources show up in the report designer.
I want to follow the DDD philosophy and not access entity objects of an aggregate directly. So, i have to call the root object to get the associated entity. But In other cases I dont always want every associated entity to load when the root is called. Is that the purpose of lazy loading?
How do I access entity objects through the root without loading all the associated objects everytime if i disable lazyloading feature of linq?
EDIT:
For example, If I have a Person as the Root Entity, and the Person has Name, Addresses and OwnedProperties. If I want to get a list of People so that I could display their names, I dont necvessarily want to load up Owned Properties every time on the call to the Repository. Conversely, on another page I may want to show a list of OwnedProperties, but do not want the other information to load with the call. what is the simple way of just calling the Person without the owned property entity other than creating a new person object without that owned properties?
I don't thinks that's possible without lazy loading.
Getting all data at once: Eager Loading
Getting data when accessed: Lazy Loading
According to your edit:
What I do in these situations, is create a 'View' class or a 'DTO' class which just contains the properties that I'm interested in.
For instance, I could have a 'PersonView' class which just has a Name property for instance.
Then, using my OR/M mapper (I use NHibernate), I create a HQL query (or Criteria query) which works on my 'Person' entity. Before I execute the query, I tell NHibernate that I want 'PersonView' objects as a result (I specify a projection). Then, NHibernate is smart enough to execute a query that only retrieves the columns that are necessary to populate the PersonView instances.
One way to avoid lazy loading is just using the object 'id'