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  • General ORM design question

    - by Calvin
    Suppose you have 2 classes, Person and Rabbit. A person can do a number of things to a rabbit, s/he can either feed it, buy it and become its owner, or give it away. A rabbit can have none or at most 1 owner at a time. And if it is not fed for a while, it may die. Class Person { Void Feed(Rabbit r); Void Buy(Rabbit r); Void Giveaway(Person p, Rabbit r); Rabbit[] rabbits; } Class Rabbit { Bool IsAlive(); Person pwner; } There are a couple of observations from the domain model: Person and Rabbit can have references to each other Any actions on 1 object can also change the state of the other object Even if no explicit actions are invoked, there can still be a change of state in the objects (e.g. Rabbit can be starved to death, and that causes it to be removed from the Person.rabbits array) As DDD is concerned, I think the correct approach is to synchronize all calls that may change the states in the domain model. For instance, if a Person buys a Rabbit, s/he would need to acquire a lock in Person to make a change to the rabbits array AND also another lock in Rabbit to change its owner before releasing the first one. This would prevent a race condition where 2 Persons claim to be the owner of the little Rabbit. The other approach is to let the database to handle all these synchronizations. Who makes the first call wins, but then the DB needs to have some kind of business logics to figure out if it is a valid transaction (e.g. if a Rabbit already has an owner, it cannot change its owner unless the Person gives it away). There are both pros/cons in either approach, and I’d expect the “best” solution would be somewhere in-between. How would you do it in real life? What’s your take and experience? Also, is it a valid concern that there can be another race condition the domain model has committed its change but before it is fully committed in the database? And for the 3rd observation (i.e. state change due to time factor). How will you do it?

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  • Mongoid Embeds_many won't save on nested form

    - by Brandon J McKay
    I've got an embeds_many association I'm trying to set up which I've done successfully before, but I'm trying to do it all in one nested form and I can't figure it out. Let's say we have a pocket model: class Pocket include Mongoid::Document field :title, type: String embeds_many :coins, cascade_callbacks: true end and a Coin Model: class Coin include Mongoid::Document field :name, type: String embedded_in :pocket end in my form for the pocket, I'm using: = f.fields_for @pocket.coins do |coin| = coin.text_field :name My controller is the default scaffolded controller. When I use the console, it saves fine and I can see the new pocket and coin I've created. But when I try to create or update a coin from the form, the pocket saves but the coin remains unchanged. What am I missing here?

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  • Reading directly from the Doctrine Searchable index table

    - by phidah
    I've got a Doctrine table with the Searchable behavior enabled. Whenever a record is created, an index is made in another table. I have a model called Entry and the behavior automatically created the table entry_index. My question now is: How can I - without using the search(...) methods of my model use the data from this table? I want to create a tag cloud of the words most used, and the data in the index table is exactly what I need.

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  • Django: way to test what class a generic relation content_object is?

    - by bitbutter
    In my project I have a class, NewsItem. Instances of NewsItem act like a wrapper. They can be associated with either an ArtWork instance, or an Announcement instance. Here's how the NewsItem model looks: class NewsItem(models.Model): content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') date = models.DateTimeField(default=datetime.datetime.now,) class Meta: ordering = ('-date',) def __unicode__(self): return (self.title()) In a template I'm dealing with a NewsItem instance, and would like to output a certain bunch of html it it's 'wrapping' an Artwork instance, and a different bunch of html if it's wrapping an Announcement instance. Could someone explain how I can write a conditional to test for this? My first naive try looked like this: {% if news_item.content_object.type=='Artwork' %}do this{% else %}do that{% endif %}

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  • CakePHP Shell issue

    - by aboxy
    Hello, I am just getting started with Cakephp shell and running into issues. My cake core library is under path d:/libs/cake My app is setup under d:/servers/htdocs/myapp I wrote a test shell under d:/servers/htdocs/myapp/vendor/shells class ReportShell extends Shell { var $uses = array('Appt'); function main() { echo $this->Appt->find('first'); } } When I try to run this code from d:/servers/htdocs/myapp , It gives me an error Warning: include_once(d:/servers/htdocs/myapp/config/database.php): failed to open stream: No such file or directory in d:/libs/cake\libs\mode l\connection_manager.php on line 23 Warning: include_once(): Failed opening 'd:/servers/htdocs/myapp/config/database.php' for inclusion (include_path='.;D:\work\xampp\php\PEAR') in d:/libs/cake\libs\model\connection_manager.php on line 23 Fatal error: ConnectionManager::getDataSource - Non-existent data source default in d:/libs/cake\libs\model\connection_manager.php on line 102 Reason is that it is trying to find database.php under 'd:/servers/htdocs/myapp/config/' and the correct path is 'd:/servers/htdocs/myapp/app/config/database.php' What am I doing wrong here? thanks

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  • gparted dont figure any partition

    - by radi
    hi all , i am trying to install ununtu 10.04 lts on my laptop , first i installed it inside windows and when it boot for first time i got the error message "dont find root file system , try partition table to fix the problem " . and when i want to install it on a single partition (normally) and when it told me to chose a partition i dont find any partition (entire disk) . i have 2 primary partitions and 3 logical partitions . please help me thanks .

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  • System.Timers.Timer leaking due to "direct delegate roots"

    - by alimbada
    Apologies for the rather verbose and long-winded post, but this problem's been perplexing me for a few weeks now so I'm posting as much information as I can in order to get this resolved quickly. We have a WPF UserControl which is being loaded by a 3rd party app. The 3rd party app is a presentation application which loads and unloads controls on a schedule defined by an XML file which is downloaded from a server. Our control, when it is loaded into the application makes a web request to a web service and uses the data from the response to display some information. We're using an MVVM architecture for the control. The entry point of the control is a method that is implementing an interface exposed by the main app and this is where the control's configuration is set up. This is also where I set the DataContext of our control to our MainViewModel. The MainViewModel has two other view models as properties and the main UserControl has two child controls. Depending on the data received from the web service, the main UserControl decides which child control to display, e.g. if there is a HTTP error or the data received is not valid, then display child control A, otherwise display child control B. As you'd expect, these two child controls bind two separate view models each of which is a property of MainViewModel. Now child control B (which is displayed when the data is valid) has a RefreshService property/field. RefreshService is an object that is responsible for updating the model in a number of ways and contains 4 System.Timers.Timers; a _modelRefreshTimer a _viewRefreshTimer a _pageSwitchTimer a _retryFeedRetrievalOnErrorTimer (this is only enabled when something goes wrong with retrieving data). I should mention at this point that there are two types of data; the first changes every minute, the second changes every few hours. The controls' configuration decides which type we are using/displaying. If data is of the first type then we update the model quite frequently (every 30 seconds) using the _modelRefreshTimer's events. If the data is of the second type then we update the model after a longer interval. However, the view still needs to be refreshed every 30 seconds as stale data needs to be removed from the view (hence the _viewRefreshTimer). The control also paginates the data so we can see more than we can fit on the display area. This works by breaking the data up into Lists and switching the CurrentPage (which is a List) property of the view model to the right List. This is done by handling the _pageSwitchTimer's Elapsed event. Now the problem My problem is that the control, when removed from the visual tree doesn't dispose of it's timers. This was first noticed when we started getting an unusually high number of requests on the web server end very soon after deploying this control and found that requests were being made at least once a second! We found that the timers were living on and not stopping hours after the control had been removed from view and that the more timers there were the more requests piled up at the web server. My first solution was to implement IDisposable for the RefreshService and do some clean up when the control's UnLoaded event was fired. Within the RefreshServices Dispose method I've set Enabled to false for all the timers, then used the Stop() method on all of them. I've then called Dispose() too and set them to null. None of this worked. After some reading around I found that event handlers may hold references to Timers and prevent them from being disposed and collected. After some more reading and researching I found that the best way around this was to use the Weak Event Pattern. Using this blog and this blog I've managed to work around the shortcomings in the Weak Event pattern. However, none of this solves the problem. Timers are still not being disabled or stopped (let alone disposed) and web requests are continuing to build up. Mem Profiler tells me that "This type has N instances that are directly rooted by a delegate. This can indicate the delegate has not been properly removed" (where N is the number of instances). As far as I can tell though, all listeners of the Elapsed event for the timers are being removed during the cleanup so I can't understand why the timers continue to run. Thanks for reading. Eagerly awaiting your suggestions/comments/solutions (if you got this far :-p)

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  • Possible to use Tables of same type in Linq to SQL?

    - by Schneider
    Lets say I've got an object model, where I have many collections of the same type. For example something like class StockMarketData { List<SummaryData> WeeklySummary; List<SummaryData> MonthlySummary; } class SummaryData { DateTime DateTime {get; set;} double Value {get; set;} } Those lists will map onto database tables. If you actually use L2S to generate a model from the database you will get something like: class StockMarketData { List<WeeklySummaryData> WeeklySummary; List<MonthlySummaryData> MonthlySummary; } Even though WeeklySummaryData and MonthlySummaryData have the same shape. Is it possible for Linq to SQL to create tables from a database of summary data, but get each table to contain the same type (such as shown in the top example).

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  • setting codeigniter mysql datetime column to time() always sets it to 0

    - by Jake
    Hi guys. I'm using Codeigniter for a small project, and my model works correctly except for the dates. I have a column defined: created_at datetime not null and my model code includes in its array passed into db-insert: 'created_at' = time() This produces a datetime value of 0000-00-00 00:00:00. When I change it to: 'created_at' = "from_unixtime(" . time() . ")" it still produces the 0 datetime value. What am I doing wrong? How can I set this field to the given unix time? Also, I know mysql sets TIMESTAMP columns automatically for you - I'm not interested in that solution here. So far I can't find a complete example of this on the web.

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  • How to limit number of displayed items in html.dropdownlist?

    - by Remnant
    I have a html.dropdownlist on my webpage as follows: <%=Html.DropDownList("MyDropDown", Model.Data, new { @class = "dropdown"})%> I am populating the dropdown with ~80 items. The issue is that when I click the dropdown the list of items is rendered from the top of the screen to the bottom of the screen. How can I set up the dropdownlist so that it only displays a maximum of 20 items when the dropdown menu is clicked (i.e. user needs to scroll down to see items 21 - 80)? I was anticipating (!) that there would be a html.dropdownlist property to control the number of displayed items that would allow something like the following e.g.: <% =Html.DropDownList("MyDropDown", Model.Data, new { @class = "dropdown", rows ="20"}) %> From research I have been doing on the msdn website it appears that there is no such property and that each browser has its own rules of how many items are displayed in a dropdownlist (?). I am using IE6 and IE7.

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  • Ruby on Rails - Create Entity with Relationship

    - by SooDesuNe
    I'm new to rails, so be nice. I'm building a "rolodex" type application, and this question is about the best way to handle creating an entity along with several relationship entities at the same time. For (a contrived) example: My application will have a Person model, which has_one Contact_Info model. On the create.html.erb page for Person it makes sense for the user of my appliction to create the person, and the contact_info at the same time. It doesn't seem right to include details for creating a contact directly in the create view/controller for person. What's the rails way to handle this?

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  • Gparted doesn't detect any partitions

    - by radi
    I am trying to install Ubuntu 10.04 LTS on my laptop. First I installed it inside Windows and when it boots for first time I got the error message "couldn't find root filesystem , try partition table to fix the problem " . When I want to install it on a single partition (normally) and when it told me to chose a partition I don't find any partition (entire disk) . I have 2 primary partitions and 3 logical partitions. How can I proceed with the install ?

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  • Clean Method for a ModelForm in a ModelFormSet made by modelformset_factory

    - by Salyangoz
    I was wondering if my approach is right or not. Assuming the Restaurant model has only a name. forms.py class BaseRestaurantOpinionForm(forms.ModelForm): opinion = forms.ChoiceField(choices=(('yes', 'yes'), ('no', 'no'), ('meh', 'meh')), required=False, )) class Meta: model = Restaurant fields = ['opinion'] views.py class RestaurantVoteListView(ListView): queryset = Restaurant.objects.all() template_name = "restaurants/list.html" def dispatch(self, request, *args, **kwargs): if request.POST: queryset = self.request.POST.dict() #clean here return HttpResponse(json.dumps(queryset), content_type="application/json") def get_context_data(self, **kwargs): context = super(EligibleRestaurantsListView, self).get_context_data(**kwargs) RestaurantFormSet = modelformset_factory( Restaurant,form=BaseRestaurantOpinionForm ) extra_context = { 'eligible_restaurants' : self.get_eligible_restaurants(), 'forms' : RestaurantFormSet(), } context.update(extra_context) return context Basically I'll be getting 3 voting buttons for each restaurant and then I want to read the votes. I was wondering from where/which clean function do I need to call to get something like: { ('3' : 'yes'), ('2' : 'no') } #{ 'restaurant_id' : 'vote' } This is my second/third question so tell me if I'm being unclear. Thanks.

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  • Trying to implement a method that can compare any two lists but it always returns false

    - by Tyler Pfaff
    Hello like the title says I'm trying to make a method that can compare any two lists for equality. I'm trying to compare them in a way that validates that every element of one list has the same value as every element of another list. My Equals method below always returns false, can anyone see why that is? Thank you! using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; public class IEnumerableComparer<T> : IEqualityComparer<IEnumerable<T>> { public bool Equals(IEnumerable<T> x, IEnumerable<T> y) { for(int i = 0; i<x.Count();i++){ if(!Object.Equals(x.ElementAt(i), y.ElementAt(i))){ return false; } } return true; } public int GetHashCode(IEnumerable<T> obj) { if (obj == null) return 0; return unchecked(obj.Select(e => e.GetHashCode()).Aggregate(0, (a, b) => a + b)); } } Here is my data I'm using to test this Equals method. static void Main(string[] args) { Car car1 = new Car(); car1.make = "Toyota"; car1.model = "xB"; Car car2 = new Car(); car2.make = "Toyota"; car2.model = "xB"; List<Car> l1 = new List<Car>(); List<Car> l2 = new List<Car>(); l1.Add(car1); l2.Add(car2); IEnumerableComparer<Car> seq = new IEnumerableComparer<Car>(); bool b = seq.Equals(l1, l2); Console.Write(b); //always says false Console.Read(); } } Car class class Car { public String make { get; set; } public String model { get; set; } }

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  • Ajax Post Request Returns JSON but Deferred Fails

    - by imrane
    I have a cross-domain POST request to http://api.local/user/auth - my API endpoint. I allow Cross Domain requests in my api with CORS. Using Chrome if that makes a difference. I get a valid server JSON response with 200 Status Code but I am using deferreds from a backbone model like so: @model.save() .fail(-> console.log 'sync fail') .success -> console.log 'sync OK' And I consistently get a 'sync fail' instead of the expected 'sync OK' Thoughts?

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  • What is difference between Where and Join in linq ?

    - by Freshblood
    hello What is difference between of these 2 queries ? they are completely equal ? from order in myDB.OrdersSet from person in myDB.PersonSet from product in myDB.ProductSet where order.Persons_Id==person.Id && order.Products_Id==product.Id select new { order.Id, person.Name, person.SurName, product.Model,UrunAdi=product.Name }; and from order in myDB.OrdersSet join person in myDB.PersonSet on order.Persons_Id equals person.Id join product in myDB.ProductSet on order.Products_Id equals product.Id select new { order.Id, person.Name, person.SurName, product.Model,UrunAdi=product.Name };

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  • ProgrammingError: (1146, "Table 'test_<DB>.<TABLE>' doesn't exist") when running unit test for Djang

    - by abigblackman
    I'm running a unit test using the Django framework and get this error. Running the actual code does not have this problem, running the unit tests creates a test database on the fly so I suspect the issue lies there. The code that throws the error looks like this member = Member.objects.get(email=email_address) and the model looks like class Member(models.Model): member_id = models.IntegerField(primary_key=True) created_on = models.DateTimeField(editable=False, default=datetime.datetime.utcnow()) flags = models.IntegerField(default=0) email = models.CharField(max_length=150, blank=True) phone = models.CharField(max_length=150, blank=True) country_iso = models.CharField(max_length=6, blank=True) location_id = models.IntegerField(null=True, blank=True) facebook_uid = models.IntegerField(null=True, blank=True) utc_offset = models.IntegerField(null=True, blank=True) tokens = models.CharField(max_length=3000, blank=True) class Meta: db_table = u'member' there's nothing too odd there i can see. the user running the tests has the same permissions to the database server as the user that runs the website where else can I look to see what's going wrong, why is this table not being created?

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  • RIA Services - Two entity models share an entity name

    - by Alex
    I have two entity models hooked up to two different databases. However, the two databases both have a table named 'brand', for example. As such, there is a naming conflict in my models. Now, I've been able to add a namespace to each model, via Custom Tool Namespace in the model's properties, but the generated code in my Silverlight project will try to use both namespaces, and come up with this, Imports MyProject.ModelA Imports MyProject.ModelB Public ReadOnly Property brands() As EntitySet(Of brand) Get Return MyBase.EntityContainer.GetEntitySet(Of brand) End Get End Property giving me this exception: 'Error 1 'brand' is ambiguous, imported from the namespaces or types 'MyProject.ModelA,MyProject.ModelB'. Has anyone had experience with naming conflicts like this using RIA services? How did you solve it?

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  • How do I use the html 'title' attribute with Html.Encode()?

    - by Kai
    Hello, I've been tryin to find an example of the syntax for getting an html 'title' for a string when using Html.Encode(). I want to display the full name in the mouseover title, if it's too long. Is there a way to do this without wrapping the string in a < span , i.e. <span title = "<%=Html.Encode(model.Name) %>"> //displays the full name on mouseover <%=Html.Encode(model.Name.Substring(0, 10))%>... //displays the name up to a max length </span> Or should I just do it this way? Thanks!

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  • Ubuntu hardware wireless switch has no effect after suspend and 13.10 upgrade

    - by blaineh
    I'm posting this on SU after it stalled on askubuntu. I hope someone here can help! If you'd prefer to answer on AU itself, here's the link: http://askubuntu.com/questions/365177/hardware-wireless-switch-has-no-effect-after-suspend-and-13-10-upgrade Wireless works fine after a reboot, but after a suspend the hardware switch (for my laptop this is f12) has no effect on the wireless, it is just permanently off, and shows that it is with a red LED. My rfkill list all reads: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: yes 1: hp-wifi: Wireless LAN Soft blocked: no Hard blocked: yes Any combination with rfkill <un>block wifi doesn't work, although one time first blocking then unblocking actually turned it on again. sudo lshw -C network reads: *-network DISABLED description: Wireless interface product: AR9285 Wireless Network Adapter (PCI-Express) vendor: Qualcomm Atheros physical id: 0 bus info: pci@0000:02:00.0 logical name: wlan0 version: 01 serial: 78:e4:00:65:2e:3f width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.11.0-12-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:90100000-9010ffff *-network DISABLED description: Ethernet interface product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:03:00.0 logical name: eth0 version: 02 serial: c8:0a:a9:89:b4:30 size: 10Mbit/s capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half latency=0 link=no multicast=yes port=MII speed=10Mbit/s resources: irq:42 ioport:2000(size=256) memory:90010000-90010fff memory:90000000-9000ffff memory:90020000-9002ffff Also, adding a /etc/pm/sleep.d/brcm.sh file as recommended here simply prevents the laptop from suspending at all, which of course is no good. This question has an answer urging to install the original driver, but it wasn't an "accepted answer" so I'd rather not take a chance on it. Also I'll admit I'm a bit lost on that and would like help doing so with the specific information I've given. I would be happy to provide more information, so long as you're willing to help me find it for you! This is a very annoying bug. I have a Compaq Presario CQ62. Edit. Output of lspci | grep Network: 02:00.0 Network controller: Qualcomm Atheros AR9285 Wireless Network Adapter (PCI-Express) (rev 01) Edit. This morning, I had had the laptop suspended all night, and then when I tried to awake it, it simply wouldn't. It would try, and then it would sleep again (I guess it felt a little bit like me! </badjoke>). Is it possible these problems are related? Edit. I don't have enough reputation on SU proper to post links to pastebins and other questions I've tried, so I'm putting them in comments, and of course they're available in the original question.

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  • ComboBox SelectedItem vs SelectedValue

    - by Anna Lear
    The following code works as you’d expect — MyProperty on the model is updated when the user picks a new item in the dropdown. comboBox1.DataBindings.Add("SelectedValue", myModel, "MyProperty", true, DataSourceUpdateMode.OnPropertyChanged); The following, however, doesn’t work the same way and the model update isn’t triggered until the input focus moves to another control on the form: comboBox1.DataBindings.Add("SelectedItem", myModel, "MyProperty", true, DataSourceUpdateMode.OnPropertyChanged); Does anybody know why? I don’t even know where to start investigating the cause. Pointers in the right direction to start the investigation or an outright explanation would be equally appreciated. Thanks.

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