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  • many to many and integrity when saving the null

    - by user369759
    I have two classes Software, Tag - they are related by ManyToMany. We CAN NOT create Software without putting the Tag to it. I want to write a test which check that: @Test public void createSoftwareWithNullTags() { List<Tag> tags = null; Software software = new Software("software1", "description1", tags); try { software.save(); fail("tags should not be null"); } catch (Exception ex) { // NEVER COME HERE !!! } } So, this test fails. I guess it is not good test for that case - because it even do not try to SAVE data to SOFTWARE_TAG table. Of course i could do validation manually but i want implement it with hibernate, using some annotation or something. Is it possible? Or how would you do this? My entities: @Entity public class Tag extends Model { public String title; public Tag(String title) { this.title = title; } @ManyToMany( cascade = {CascadeType.ALL}, mappedBy = "tags", targetEntity = Software.class ) public List<Software> softwares; } @Entity public class Software extends Model { public String title; public String description; @ManyToOne(optional = false) public Author author; @ManyToMany(cascade = CascadeType.ALL) @JoinTable( name = "SOFTWARE_TAG", joinColumns = @JoinColumn(name = "Software_id"), inverseJoinColumns = @JoinColumn(name = "Tag_id") ) public List<Tag> tags; public Software(String title, String description, Author author, List<Tag> tags) { this.title = title; this.description = description; this.author = author; this.tags = tags; } }

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  • Applying correct bindings to WPF datatemplate to maximize reusability

    - by johncatfish
    Hi. I have a WPF application. I want to apply that datatemplate to a Listbox filled with records from Table02. Then, for each listboxitem I need to bind the combobox to the same database table (Table01), but for each listboxitem the selected item will vary. It will be a foreign key to Table01. <DataTemplate x:Key="Table01DataTemplate"> <Grid> <ComboBox ItemsSource="{Binding Model.IQueryable_Table01, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" SelectedValue="{Binding Table01_ForeignKey}" DisplayMemberPath="name" SelectedValuePath="id" /> <!-- Other stuff --> </Grid> </DataTemplate> <ListBox x:Name="lbTest" ItemTemplate="{StaticResource Table01DataTemplate}" /> <!-- In .cs file lbTest.DataContext = this; --> Notes: Model.IQueryable_Table01 is a property which encapsulates a Linq-to-sql call returning a IQueryable. lbTest will be filled by setting ItemsSource with a Linq-to-sql call. Is this a good way to do the bindings in a data template for a maximum reusability? I also thought of replacing AncestorType={x:Type Window} with lbTest.DataContext = this; AncestorType={x:Type Application} and lbTest.DataContext = App.Current; But it didn't work (Exception on loading) and I don't know if there's any caveats or down-sides to this approach. Is this good? Any suggestions or improvements? Thanks.

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  • Adding Categories to my Articles in my Rails app (Small Help)

    - by user214038
    I'm currently building a semi-small ruby app for a project. The problem I'm currently facing is the following: I want to be Able to fit the Article into the Categories. I've already accomplish this by having two models. An article model with a foreign key of category_id and my Category model with the name of the category. With a has_one and belogs_to relationship. (We're assuming you can only fit an article into one category). Here's the piece of code. This is the new method, where i create a new article and load up all the categories. def new @article = Article.new @categories = Category.find(:all) end The problem comes when i try to get the category from a combo box in order to insert it along with the article. This is the combo box code : f.select(:category_id,@categories) And this is the create method: def create @category = Category.find(params[:id]) @article = @category.articles.new(params[:article]) if @article.save flash[:notice] = "Article Submitted Sucessfully" redirect_to user_path else render :action = 'new' end end I believe that the problem i have is in this line when i try to load up the selected category "@category = Category.find(params[:id])" because whenever i hardcode the this line into @category = Category.find(1) It Works perfectly

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  • Why is my django bulk database population so slow and frequently failing?

    - by bryn
    I decided I'd like to use django's model system rather than coding raw SQL to interface with my database, but I am having a problem that surely is avoidable. My models.py contains: class Student(models.Model): student_id = models.IntegerField(unique = True) form = models.CharField(max_length = 10) preferred = models.CharField(max_length = 70) surname = models.CharField(max_length = 70) and I'm populating it by looping through a list as follows: from models import Student for id, frm, pref, sname in large_list_of_data: s = Student(student_id = id, form = frm, preferred = pref, surname = sname) s.save() I don't really want to be saving this to the database each time but I don't know another way to get django to not forget about it (I'd rather add all the rows and then do a single commit). There are two problems with the code as it stands. It's slow -- about 20 students get updated each second. It doesn't even make it through large_list_of_data, instead throwing a DatabaseError saying "unable to open database file". (Possibly because I'm using sqlite3.) My question is: How can I stop these two things from happening? I'm guessing that the root of both problems is that I've got the s.save() but I don't see a way of easily batching the students up and then saving them in one commit to the database.

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  • Sonata Media Bundle sortBy created_at

    - by tony908
    I use SonataMediaBundle and i would like sort Gallery by created_at field. In repository class i have (without orderBy working good!): $qb = $this->createQueryBuilder('m') ->orderBy('j.expires_at', 'DESC'); $query = $qb->getQuery(); return $query->getResult(); and this throw error: An exception has been thrown during the rendering of a template ("[Semantical Error] line 0, col 80 near 'created_at D': Error: Class Application\Sonata\MediaBundle\Entity\Gallery has no field or association named created_at") so i add this field to Gallery class: /** * @var \DateTime */ private $created_at; /** * Set created_at * * @param \DateTime $createdAt * @return Slider */ public function setCreatedAt($createdAt) { $this->created_at = $createdAt; return $this; } /** * Get created_at * * @return \DateTime */ public function getCreatedAt() { return $this->created_at; } but now i have error: FatalErrorException: Compile Error: Declaration of Application\Sonata\MediaBundle\Entity\Gallery::setCreatedAt() must be compatible with Sonata\MediaBundle\Model\GalleryInterface::setCreatedAt(DateTime $createdAt = NULL) in /home/tony/www/test/Application/Sonata/MediaBundle/Entity/Gallery.php line 32 GalleryInterface: https://github.com/sonata-project/SonataMediaBundle/blob/master/Model/GalleryInterface.php So... how can i use sortBy in my example?

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  • My first MVVM application architecture setup

    - by 1110
    Ok, time is coming for my first WPF project :). I work before with Flex and PureMVC and I know how project setup is important in RIA's. I decided to work with MVVM. And decided to work with PRISM framework. Application is somethin like operating system. There will be 'shell' (parent for smaller applications). Smaller application I plan to make like modules. So I plan to design structure of project something like this. Module_A {view, viewModel, model, assets} // for example calculator Module_B {view, viewModel, model, assets} // notebook etc I read prism doc and I see that parrent for all this modules should be shell project, and this is my main question here. Parrent_Project {App.xaml, Bootstrapper.cs, Shell.xaml} Because this shell will be fullscreen with background images (like operating system), right click with some features. Is that ok to create folder structure like in modulesXYZ for Shell.xaml here? I want to start project with good structure so any advice is welcome. Thanks

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  • Preventing ActiveRecord save() on an instance

    - by Craig Walker
    I have an ActiveRecord model object Foo; it represents a standard database row. I want to be able to display modified versions of instances of this object. I'd like to reuse the class itself, as it already has all the hooks & aspects I'll need. (For example: I already have a view that displays the appropriate attributes). Basically I want to clone the model instance, modify some of its properties, and feed it back to the caller (view, test, etc). I do not want these attribute modifications getting back into the database. However, I do want to include the id attribute in the cloned version, as it makes dealing with the route-helpers much easier. Thus, I plan on calling ActiveRecord::Base.clone(), manually setting the ID of the cloned instance, and then making the appropriate attribute changes to the new instance. This has me worried though; one save() on the modified instance and my original data will get clobbered. So, I'm looking to lock down the new instance so that it won't hurt anything else. I'm already planning on calling freeze() (on the understanding that this prevents further modification to the object, though the documentation isn't terribly clear). However, I don't see any obvious way to prevent a save(). What would be the best approach to achieving this?

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  • NSFetchedResultsController on secondary UITableView - how to query data?

    - by Jason
    I am creating a core-data based Navigation iPhone app with multiple screens. Let's say it is a flash-card application. The data model is very simple, with only two entities: Language, and CardSet. There is a one-to-many relationship between the Language entity and the CardSet entities, so each Language may contain multiple CardSets. In other words, Language has a one-to-many relationship Language.cardSets which points to the list of CardSets, and CardSet has a relationship CardSet.language which points to the Language. There are two screens: (1) An initial TableView screen, which displays the list of languages; and (2) a secondary TableView screen, which displays the list of CardSets in the Language. In the initial screen, which lists the languages, I am using NSFetchedResultsController to keep the list of languages up-to-date. The screen passes the Language selected to the secondary screen. On the secondary screen, I am trying to figure out whether I should again use an NSFetchedResultsController to maintain the list of CardSets, or if I should work through Language.cardSets to simply pull the list out of the object model. The latter makes the most sense programatically because I already have the Language - but then it would not automatically be updated on changes. I have looked at the NSFetchedResultsController documentation, and it seems like I can easily create predicates based on attributes - but not relationships. I.e., I can create the following NSFetchedResultsController: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name LIKE[c] 'Chuck Norris'"]; How can I access my data through the direct relationship - Language.cardSets - and also have the table auto-update using NSFetchedResultsController? Is this possible?

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  • django join-like expansion of queryset

    - by jimbob
    I have a list of Persons each which have multiple fields that I usually filter what's upon, using the object_list generic view. Each person can have multiple Comments attached to them, each with a datetime and a text string. What I ultimately want to do is have the option to filter comments based on dates. class Person(models.Model): name = models.CharField("Name", max_length=30) ## has ~30 other fields, usually filtered on as well class Comment(models.Model): date = models.DateTimeField() person = models.ForeignKey(Person) comment = models.TextField("Comment Text", max_length=1023) What I want to do is get a queryset like Person.objects.filter(comment__date__gt=date(2011,1,1)).order_by('comment__date') send that queryset to object_list and be able to only see the comments ordered by date with only so many objects on a page. E.g., if "Person A" has comments 12/3/11, 1/2/11, 1/5/11, "Person B" has no comments, and person C has a comment on 1/3, I would see: "Person A", 1/2 - comment "Person C", 1/3 - comment "Person A", 1/5 - comment I would strongly prefer not to have to switch to filtering based on Comments.objects.filter(), as that would make me have to largely repeat large sections of code in the both the view and template. Right now if I tried executing the following command, I will get a queryset returning (PersonA, PersonC, PersonA), but if I try rendering that in a template each persons comment_set will contain all their comments even if they aren't in the date range. Ideally they're would be some sort of functionality where I could expand out a Person queryset's comment_set into a larger queryset that can be sorted and ordered based on the comment and put into a object_list generic view. This normally is fairly simple to do in SQL with a JOIN, but I don't want to abandon the ORM, which I use everywhere else.

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  • Should I invest in GraniteDS for Flex + Java development?

    - by Boden
    I'm new to Flex development, and RIAs in general. I've got a CRUD-style Java + Spring + Hibernate service on top of which I'm writing a Flex UI. Currently I'm using BlazeDS. This is an internal application running on a local network. It's become apparent to me that the way RIAs work is more similar to a desktop application than a web application in that we load up the entire model and work with it directly on the client (or at least the portion that we're interested in). This doesn't really jive well with BlazeDS because really it only supports remoting and not data management, thus it can become a lot of extra work to make sure that clients are in sync and to avoid reloading the model which can be large (especially since lazy loading is not possible). So it feels like what I'm left with is a situation where I have to treat my Flex application more like a regular old web application where I do a lot of fine grained loading of data. LiveCycle is too expensive. The free version of WebOrb for Java really only does remoting. Enter GraniteDS. As far as I can determine, it's the only free solution out there that has many of the data management features of LiveCycle. I've started to go through its documentation a bit and suddenly feel like it's yet another quagmire of framework that I'll have to learn just to get an application running. So my question(s) to the StackOverflow audience is: 1) do you recommend GraniteDS, especially if my current Java stack is Spring + Hibernate? 2) at what point do you feel like it starts to pay off? That is, at what level of application complexity do you feel that using GraniteDS really starts to make development that much better? In what ways?

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  • How do I DRY up business logic between sever-side Ruby and client-side Javascript?

    - by James A. Rosen
    I have a Widget model with inheritance (I'm using Single-Table Inheritance, but it's equally valid for Class-per-Table). Some of the subclasses require a particular field; others do not. class Widget < ActiveRecord ALL_WIDGET_TYPES = [FooWidget, BarWidget, BazWidget] end class FooWidget < Widget validates_presence_of :color end class BarWidget < Widget # no color field end class BazWidget < Widget validates_presence_of :color end I'm building a "New Widget" form (app/views/widgets/new.html.erb) and would like to dynamically show/hide the color field based on a <select> for widget_type. <% form_for @widget do |f| %> <%= f.select :type, Widget::ALL_WIDGET_TYPES %> <div class='hiddenUnlessWidgetTypeIsFooOrBaz'> <%= f.label :color %> <%= f.text_field :color %> </div> <% end %> I can easily write some jQuery to watch for onChange events on widget_type, but that would mean putting some sort of WidgetTypesThatRequireColor constant in my Javascript. Easy enough to do manually, but it is likely to get disconnected from the Widget model classes. I would prefer not to output Javascript directly in my view, though I have considered using content_for(:js) and have a yield :js in my template footer. Any better ideas?

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  • MVVM: Do I need Inheritance with ViewModels A + B ?

    - by Lisa
    Hello guys my first post on SO because EE sucks in the meantime ;P I am using wpf and mvvm in my desktop application. Scenario: I have a calendar with week A and week B which are rotating by every X week depending on the user settings. But the UserControl "week B" is only visible when the user sets the option "rotating weeks"... The UserControl with week A has a DataGrid and for week B I want to use the same UserControl of course. What I want to achieve is that all data entered/choosen by the user in the Week A is saved/backed by a ViewModel A and Model C. When the user wants a rotating weekly calendar plan I need also a ViewModel B and again Model C. The reason why I need to know what data entered by the user belongs to week A or week B is because I have to write the entered data in a certain order into the database = db.Write(weekA),db.Write(weekB),db.Write(weekA),etc... I am unsure how a solution could look like... What would you do to identify a ViewModel A or B so you know the order of how to write the data in the proper order into database? Any other suggestions are also welcome of course, maybe I think in the wrong direction its late here :) I am new to mvvm so please be patient.

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  • Two Applications using the same index file with Hibernate Search

    - by Dominik Obermaier
    Hi, I want to know if it is possible to use the same index file for an entity in two applications. Let me be more specific: We have an online Application with a frondend for the users and an application for the backend tasks (= administrator interface). Both are running on the same JBOSS AS. Both Applications are using the same database, so they are using the same entities. Of course the package names are not the same in both applications for the entities. So this is our usecase: A user should be able to search via the frondend. The user is only allowed to see results which are tagged with "visible". This tagging happens in our admin interface, so the index for the frontend should be updated every time an entity is tagged as "visible" in the backend. Of course both applications do have the same index root folder. In my index folder there are 2 index files: de.x.x.admin.model.Product de.x.x.frondend.model.Product How to "merge" this via Hibernate Search Configuration? I just did not get it via the documentation... Thanks for any help!

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  • Accessing data entered into multiple Django forms and generating them onto a new URL

    - by pedjk
    I have a projects page where users can start up new projects. Each project has two forms. The two forms are: class ProjectForm(forms.Form): Title = forms.CharField(max_length=100, widget=_hfill) class SsdForm(forms.Form): Status = forms.ModelChoiceField(queryset=P.ProjectStatus.objects.all()) With their respective models as follows: class Project(DeleteFlagModel): Title = models.CharField(max_length=100) class Ssd(models.Model): Status = models.ForeignKey(ProjectStatus) Now when a user fills out these two forms, the data is saved into the database. What I want to do is access this data and generate it onto a new URL. So I want to get the "Title" and the "Status" from these two forms and then show them on a new page for that one project. I don't want the "Title" and "Status" from all the projects to show up, just for one project at a time. If this makes sense, how would I do this? I'm very new to Django and Python (though I've read the Django tutorials) so I need as much help as possible. Thanks in advance Edit: The ProjectStatus code is (under models): class ProjectStatus(models.Model): Name = models.CharField(max_length=30) def __unicode__(self): return self.Name

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  • WPF data-bound ComboBox only shows first item of ItemsSource list

    - by Mark
    Hi all, I'm sure I'm doing something stupid but for the life of me I can't think of right now. I have a ComboBox that is data-bound to a list of Layout objects. The list is initially empty but things are added over time. When the list is updated by the model the first time, this update reflects properly in the ComboBox. However, subsequent updates never show up in the ComboBox even though I can see that the list itself contains these items. Since the first update works, I know the data-binding is OK - so what am I doing wrong here? Here's the XAML (abridged): <Grid HorizontalAlignment="Stretch"> <ComboBox ItemsSource="{Binding Path=SavedLayouts, diagnostics:PresentationTraceSources.TraceLevel=High}" DisplayMemberPath="Name" SelectedValuePath="Name" SelectedItem="{Binding LoadLayout}" Height="25" Grid.Row="1" Grid.Column="0"></ComboBox> </Grid> And the related part of the model: public IList<Layout> SavedLayouts { get { return _layouts; } } public Layout SaveLayout( String data_ ) { Layout theLayout = new Layout( SaveLayoutName ); _layouts.Add( theLayout ); try { return theLayout; } finally { PropertyChangedEventHandler handler = PropertyChanged; if( handler != null ) { handler( this, new PropertyChangedEventArgs( "SavedLayouts" ) ); } } } And finally, the layout class (abridged): public class Layout { public String Name { get; private set; } } In the output window, I can see the update occurring: System.Windows.Data Warning: 91 : BindingExpression (hash=64564967): Got PropertyChanged event from TickerzModel (hash=43624632) System.Windows.Data Warning: 97 : BindingExpression (hash=64564967): GetValue at level 0 from TickerzModel (hash=43624632) using RuntimePropertyInfo(SavedLayouts): List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 76 : BindingExpression (hash=64564967): TransferValue - got raw value List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 85 : BindingExpression (hash=64564967): TransferValue - using final value List`1 (hash=16951421 Count=11) But I get do not get this 11th item in the ComboBox. Any ideas?

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  • Prohibit ampersand in Rails form

    - by snlsn
    NOT a Rails 3 issue In a Contact model I have a company_name attribute. For reasons that don't matter to this question, I want to prohibit an ampersand character. We have a lot of clients with ampersands in their company name, and users forget they aren't allowed to use this character. This isn't an html sanitize issue. I don't care about whitespace or CDATA or anything. The entries in this field are plain text and I don't want an ampersand to be entered in this one field in any way, shape or form. I assume a validation on the model is the way to go. I have tried validates_exclusion_of. I have tried validates_format_of. No success. I'm unsophisticated when it comes to regex, so I might be doing things very wrong. But the bottom line is - I need to prevent a user from entering that "&" character in the company_name field. Thanks a million. Steve

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  • CodeIgniter: problem using foreach in view

    - by krike
    I have a model and controller who gets some data from my database and returns the following array Array ( [2010] => Array ( [year] => 2010 [months] => Array ( [0] => stdClass Object ( [sales] => 2 [month] => Apr ) [1] => stdClass Object ( [sales] => 1 [month] => Nov ) ) ) [2011] => Array ( [year] => 2011 [months] => Array ( [0] => stdClass Object ( [sales] => 1 [month] => Nov ) ) ) ) It shows exactly what it should show but the key's have different names so I have no idea on how to loop through the years using foreach in my view. Arrays is something I'm not that good at yet :( this is the controller if you need to know: function analytics() { $this->load->model('admin_model'); $analytics = $this->admin_model->Analytics(); foreach ($analytics as $a): $data[$a->year]['year'] = $a->year; $data[$a->year]['months'] = $this->admin_model->AnalyticsMonth($a->year); endforeach; echo"<pre style='text-align:left;'>"; print_r($data); echo"</pre>"; $data['main_content'] = 'analytics'; $this->load->view('template_admin', $data); }//end of function categories()

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  • NHibernate many-to-many mapping

    - by Scozzard
    Hi, I am having an issue with many-to-many mapping using NHibernate. Basically I have 2 classes in my object model (Scenario and Skill) mapping to three tables in my database (Scenario, Skill and ScenarioSkill). The ScenarioSkills table just holds the IDs of the SKill and Scenario table (SkillID, ScenarioID). In the object model a Scenario has a couple of general properties and a list of associated skills (IList) that is obtained from the ScenarioSkills table. There is no associated IList of Scenarios for the Skill object. The mapping from Scenario and Skill to ScenarioSkill is a many-to-many relationship: Scenario * --- * ScenarioSkill * --- * Skill I have mapped out the lists as bags as I believe this is the best option to use from what I have read. The mappings are as follows: Within the Scenario class <bag name="Skills" table="ScenarioSkills"> <key column="ScenarioID" foreign-key="FK_ScenarioSkill_ScenarioID"/> <many-to-many class="Domain.Skill, Domain" column="SkillID" /> </bag> And within the Skill class <bag name="Scenarios" table="ScenarioSkills" inverse="true" access="noop" cascade="all"> <key column="SkillID" foreign-key="FK_ScenarioSkill_SkillID" /> <many-to-many class="Domain.Scenario, Domain" column="ScenarioID" /> </bag> Everything works fine, except when I try to delete a skill, it cannot do so as there is a reference constraint on the SkillID column of the ScenarioSkill table. Can anyone help me? I am using NHibernate 2 on an C# asp.net 3.5 web application solution.

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  • Entity Framework POCO objects

    - by Dan
    I'm struggling with understanding Entity Framework and POCO objects. Here's what I'm trying to achieve. 1) Separate the DAL from the Business Layer by having my business layer use an interface to my DAL. Maybe use Unity to create my context. 2) Use Entity Framework inside my DAL. I have a Domain model with objects that reside in my business layer. I also have a database full of tables that doesn't really represent my domain model. I setup Entity Framework and generated POCO objects by using the ADO.NET POCO Generator extension. This gave me an object for each table in my database. Now I want to be able to say context.GetAll<User>(); and have it return a list of my User objects. The User object is in my business layer. Is that possible? Does that make sense or am I totally off and should start over? I'm guessing I need to use the repository pattern to achieve this, but I'm not sure. Can anyone help?

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  • Problem with ModelAndView and ModelMap in AnnotationController, Springframework

    - by saltfactory
    I have a question that is a point difference between ModelAndView and ModelMap. I want to maintain modelAndView when requestMethod is "GET" and requestMethod is "POST". My modelAndView saved others. So I made modelAndView return type to "GET", "POST" methods. But, Request lost commandObject, form:errors..., if request return showForm on "POST" because request validation failed. example) private ModelAndView modelAndView; public ControllerTest{ this.modelAndView = new ModelAndView(); } @RequestMapping(method = RequestMethod.GET) public ModelAndView showForm(ModelMap model) { EntityObject entityObject = new EntityObject(); CommandObject commandObject = new CommandObject(); commandObject.setEntityObject(entityObject); model.addAttribute("commandObject", commandObject); this.modelAndView.addObject("id", "GET"); this.modelAndView.setViewName("registerForm"); return this.modelAndView; } @RequestMapping(method = RequestMethod.POST) public ModelAndView submit(@ModelAttribute("commandObject") CommandObject commandObject, BindingResult result, SessionStatus status) { this.commandValidator.validate(commandObject, result); if (result.hasErrors()) { this.modelAndView.addObject("id", "POST"); this.modelAndView.setViewName("registerForm"); return this.modelAndView; } else { this.modelAndView.addObject("id", "after POST"); this.modelAndView.setViewName("success"); } status.setComplete(); return this.modelAndView; }

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  • IOS : BAD ACCESS when trying to add a new Entity object

    - by Maverick447
    So i'm using coredata to model my relationships . This is the model in brief Type A can have one or more types of type B Type B has a inverse relationship of being associated with one of type A Type B can have one or more types of type C Type C has a inverse relationship of being associated with one of type B From a UI standpoint , I have a Navigation controller with controllers that successively sets up the first A object (VC-1) , then another viewcontroller (VC-2) creates a B object ( I pass in the A object to this controller) and the B object is added to the A object . Similarly the same thing happens with B and C . The third Viewcontroller (VC3) first creates a C object and assigns it to the passed B Object . Also between these viewcontrollers the managedObjectCOntext is also passed . SO my use case is such that while viewcontroller (VC-3) is the top controller a button action will keep creating multiple objects of type C and add them to the same type B object that was passed . Also as part of this function I save the managedObject context after saving each type C . e.g. code in viewcontroller 3 - (void) SaveNewTypeC { TypeC *newtypeC = (Question*)[NSEntityDescription insertNewObjectForEntityForName:@"TypeC" inManagedObjectContext:managedObjectContext]; [newtypeC setProp1:] ; [newtypeC setProp2:] .. .. **[typeBObject addTypeCInTypeBObject:newtypeC];** [section setTotalCObjectCount:[ NSNumber numberWithInt:typeCIndex++]]; NSError *error = nil; if (![managedObjectContext save:&error]) { // Handle error NSLog(@"Unresolved error %@, %@, %@", error, [error userInfo],[error localizedDescription]); exit(-1); // Fail } [newtypeC release]; } - (IBAction)selectedNewButton:(id)sender { [self SaveNewTypeC]; [self startRepeatingTimer]; } The BAD ACCESS seems to appear when the bold line above executes Relating to some HashValue . Any clues on resolving this would be helpful .

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  • Schema for storing "binary" values, such as Male/Female, in a database

    - by latentflip
    Intro I am trying to decide how best to set up my database schema for a (Rails) model. I have a model related to money which indicates whether the value is an income (positive cash value) or an expense (negative cash value). I would like separate column(s) to indicate whether it is an income or an expense, rather than relying on whether the value stored is positive or negative. Question: How would you store these values, and why? Have a single column, say Income, and store 1 if it's an income, 0 if it's an expense, null if not known. Have two columns, Income and Expense, setting their values to 1 or 0 as appropriate. Something else? I figure the question is similar to storing a person's gender in a database (ignoring aliens/transgender/etc) hence my title. My thoughts so far Lookup might be easier with a single column, but there is a risk of mistaking 0 (false, expense) for null (unknown). Having seperate columns might be more difficult to maintain (what happens if we end up with a 1 in both columns? Maybe it's not that big a deal which way I go, but it would be great to have any concerns/thoughts raised before I get too far down the line and have to change my code-base because I missed something that should have been obvious! Thanks, Philip

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  • Elegant Disjunctive Normal Form in Django

    - by Mike
    Let's say I've defined this model: class Identifier(models.Model): user = models.ForeignKey(User) key = models.CharField(max_length=64) value = models.CharField(max_length=255) Each user will have multiple identifiers, each with a key and a value. I am 100% sure I want to keep the design like this, there are external reasons why I'm doing it that I won't go through here, so I'm not interested in changing this. I'd like to develop a function of this sort: def get_users_by_identifiers(**kwargs): # something goes here return users The function will return all users that have one of the key=value pairs specified in **kwargs. Here's an example usage: get_users_by_identifiers(a=1, b=2) This should return all users for whom a=1 or b=2. I've noticed that the way I've set this up, this amounts to a disjunctive normal form...the SQL query would be something like: SELECT DISTINCT(user_id) FROM app_identifier WHERE (key = "a" AND value = "1") OR (key = "b" AND value = "2") ... I feel like there's got to be some elegant way to take the **kwargs input and do a Django filter on it, in just 1-2 lines, to produce this result. I'm new to Django though, so I'm just not sure how to do it. Here's my function now, and I'm completely sure it's not the best way to do it :) def get_users_by_identifiers(**identifiers): users = [] for key, value in identifiers.items(): for identifier in Identifier.objects.filter(key=key, value=value): if not identifier.user in users: users.append(identifier.user) return users Any ideas? :) Thanks!

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  • ASP.NET MVC (VB) error when publishing to test server

    - by Colin
    I have an ASP.NET MVC project that works fine on my local machine (no build errors, server errors or anything). However, when I publish the project to a test server, I get an "Object reference not set to an instance of an object" error on a For Each I have in my view. I have a function within a model that returns a DataRowCollection. I'm calling that function in my controller and passing the DataRowCollection to my View, which then iterates over the rows and displays the necessary information: In the Controller I have: Function Index() As ActionResult Dim MyModel As New Model ViewData("MyDataRowCollection") = MyModel.GetDataRowCollection() Return View() End Function And then in the View, which is throwing the error: <%@ Page Language="VB" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %> <asp:Content ID="indexTitle" ContentPlaceHolderID="TitleContent" runat="server"> My Page Title </asp:Content> <asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server"> <% For Each MyDataRow In ViewData("MyDataRowCollection") ' do stuff with each MyDataRow Next %> I'm pretty new to ASP.NET MVC so I'm sure there might be a better way to do what I'm doing (I'd be happy to hear if there is), but my main concern is why this works fine on my local machine but throws an error on the For Each on the test server? Please let me know if I can clarify any of the above, and thanks in advance for any information.

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  • Django ManyToMany Membership errors making associations

    - by jmitchel3
    I'm trying to have a "member admin" in which they have hundreds of members in the group. These members can be in several groups. Admins can remove access for the member ideally in the view. I'm having trouble just creating the group. I used a ManytoManyField to get started. Ideally, the "member admin" would be able to either select existing Users OR it would be able to Add/Invite new ones via email address. Here's what I have: #views.py def membership(request): group = Group.objects.all().filter(user=request.user) GroupFormSet = modelformset_factory(Group, form=MembershipForm) if request.method == 'POST': formset = GroupFormSet(request.POST, request.FILES, queryset=group) if formset.is_valid(): formset.save(commit=False) for form in formset: form.instance.user = request.user formset.save() return render_to_response('formset.html', locals(), context_instance=RequestContext(request)) else: formset= GroupFormSet(queryset=group) return render_to_response('formset.html', locals(), context_instance=RequestContext(request)) #models.py class Group(models.Model): name = models.CharField(max_length=128) members = models.ManyToManyField(User, related_name='community_members', through='Membership') user = models.ForeignKey(User, related_name='community_creator', null=True) def __unicode__(self): return self.name class Membership(models.Model): member = models.ForeignKey(User, related_name='user_membership', blank=True, null=True) group = models.ForeignKey(Group, related_name='community_membership', blank=True, null=True) date_joined = models.DateField(auto_now=True, blank=True, null=True) class Meta: unique_together = ('member', 'group') Any ideas? Thank you for your help.

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