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  • Sql Server differential backup : Simple vs Full recovery model

    - by MaxiWheat
    I need to better understand the backup process under SQL Server 2008. Since drive space is a kind of matter for us and we want to have a better disaster recovery solution, I decided that we will implement differential backups throughout the day (every hour). Am I right to think that if I keep the recovery model of my databases to Simple, the differential backup will be almost the same size as Full Backup (too big to make one every hour) ? I already tried to switch to Full recovery and it seemed to have fixed the issue (differential backups were way smaller). I heard that the recovery model must be set to Full to use Log backups (to the minute recovery etc., but we don't need that) but never about differential backups. So, is the recovery model really having an impact on differential backups or am I missing something ? Thank you

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  • How to understand cpu family/model/stepping fields in /proc/cpuinfo

    - by Victor Sorokin
    I have following in cpuinfo: processor : 0 vendor_id : AuthenticAMD cpu family : 15 model : 107 model name : AMD Athlon(tm) 64 X2 Dual Core Processor 5600+ stepping : 2 According to Wikipedia page there are two kinds of 5600+ -- one of 90nm technology, another of 65nm. How can I understand which one I have? There seem to be no direct correspondence between contents of cpuinfo and info on Wikipedia page. AMD site seems to use some other naming scheme for processors too. How can I map values of family, model and stepping from cpuinfo to the data available on Wikipedia/AMD?

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  • How to understand cpu family/model/stepping fields in /proc/cpuinfo [closed]

    - by Victor Sorokin
    I have following in cpuinfo: processor : 0 vendor_id : AuthenticAMD cpu family : 15 model : 107 model name : AMD Athlon(tm) 64 X2 Dual Core Processor 5600+ stepping : 2 According to Wikipedia page there are two kinds of 5600+ -- one of 90nm technology, another of 65nm. How can I understand which one I have? There seem to be no direct correspondence between contents of cpuinfo and info on Wikipedia page. AMD site seems to use some other naming scheme for processors too. How can I map values of family, model and stepping from cpuinfo to the data available on Wikipedia/AMD?

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  • Specifying different initial values for fields in inherited models (django)

    - by Shawn Chin
    Question : What is the recommended way to specify an initial value for fields if one uses model inheritance and each child model needs to have different default values when rendering a ModelForm? Take for example the following models where CompileCommand and TestCommand both need different initial values when rendered as ModelForm. # ------ models.py class ShellCommand(models.Model): command = models.Charfield(_("command"), max_length=100) arguments = models.Charfield(_("arguments"), max_length=100) class CompileCommand(ShellCommand): # ... default command should be "make" class TestCommand(ShellCommand): # ... default: command = "make", arguments = "test" I am aware that one can used the initial={...} argument when instantiating the form, however I would rather store the initial values within the context of the model (or at least within the associated ModelForm). My current approach What I'm doing at the moment is storing an initial value dict within Meta, and checking for it in my views. # ----- forms.py class CompileCommandForm(forms.ModelForm): class Meta: model = CompileCommand initial_values = {"command":"make"} class TestCommandForm(forms.ModelForm): class Meta: model = TestCommand initial_values = {"command":"make", "arguments":"test"} # ------ in views FORM_LOOKUP = { "compile": CompileCommandFomr, "test": TestCommandForm } CmdForm = FORM_LOOKUP.get(command_type, None) # ... initial = getattr(CmdForm, "initial_values", {}) form = CmdForm(initial=initial) This feels too much like a hack. I am eager for a more generic / better way to achieve this. Suggestions appreciated. Other attempts I have toyed around with overriding the constructor for the submodels: class CompileCommand(ShellCommand): def __init__(self, *args, **kwargs): kwargs.setdefault('command', "make") super(CompileCommand, self).__init__(*args, **kwargs) and this works when I try to create an object from the shell: >>> c = CompileCommand(name="xyz") >>> c.save() <CompileCommand: 123> >>> c.command 'make' However, this does not set the default value when the associated ModelForm is rendered, which unfortunately is what I'm trying to achieve. Update 2 (looks promising) I now have the following in forms.py which allow me to set Meta.default_initial_values without needing extra code in views. class ModelFormWithDefaults(forms.ModelForm): def __init__(self, *args, **kwargs): if hasattr(self.Meta, "default_initial_values"): kwargs.setdefault("initial", self.Meta.default_initial_values) super(ModelFormWithDefaults, self).__init__(*args, **kwargs) class TestCommandForm(ModelFormWithDefaults): class Meta: model = TestCommand default_initial_values = {"command":"make", "arguments":"test"}

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  • How with lambda function in MVC3

    - by doogdeb
    I have a model which contains view models for each view. This model is held in session and is initialised when application starts. I need to be able to populate a field from one view model with the value from another so have used a lambda function. Below is my model. I am using a lambda so that when I get Test2.MyProperty it will use the FunctionTestProperty to retrieve the value from Test1.TestProperty. public class Model { public Model() { Test1 = new Test1() Test2 = new Test2(FunctionTestProperty () => Test1.TestProperty) } } public class Test1 { public string TestProperty { get; set; } } public class Test2 { public Test2() : this (() => string.Empty) {} public Test2(Func<string> functionTestProperty) { FunctionTestProperty = functionTestProperty; } public Func<string> FunctionTestProperty { get; set; } public string MyProperty { get{ return FunctionTestProperty() ?? string.Empty; } } } This works perfectly when I first run the application and navigate from Test1 to Test2; I can see that when I get the value for MyProperty it calls back to Model constructor and retrieves the Test1.TestProperty value. However when I then submit the form (Test2) it calls the default constructor which sets it to string.Empty. So if I go back to Test1 and back to Test2 again it always then calls the Test2 default constructor. Does anyone know why this works when first running the application but not after the view is submitted, or if I have made an obvious mistake?

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  • Cloud Based Load Testing Using TF Service &amp; VS 2013

    - by Tarun Arora [Microsoft MVP]
    Originally posted on: http://geekswithblogs.net/TarunArora/archive/2013/06/30/cloud-based-load-testing-using-tf-service-amp-vs-2013.aspx One of the new features announced as part of the Visual Studio 2013 Ultimate Preview is ‘Cloud Based Load Testing’. In this blog post I’ll walk you through, What is Cloud Based Load Testing? How have I been using this feature? – Success story! Where can you find more resources on this feature? What is Cloud Based Load Testing? It goes without saying that performance testing your application not only gives you the confidence that the application will work under heavy levels of stress but also gives you the ability to test how scalable the architecture of your application is. It is important to know how much is too much for your application! Working with various clients in the industry I have realized that the biggest barriers in Load Testing & Performance Testing adoption are, High infrastructure and administration cost that comes with this phase of testing Time taken to procure & set up the test infrastructure Finding use for this infrastructure investment after completion of testing Is cloud the answer? 100% Visual Studio Compatible Scalable and Realistic Start testing in < 2 minutes Intuitive Pay only for what you need Use existing on premise tests on cloud There are a lot of vendors out there offering Cloud Based Load Testing, to name a few, Load Storm Soasta Blaze Meter Blitz And others… The question you may want to ask is, why should you go with Microsoft’s Cloud based Load Test offering. If you are a Microsoft shop or already have investments in Microsoft technologies, you’ll see great benefit in the natural integration this offers with existing Microsoft products such as Visual Studio and Windows Azure. For example, your existing Web tests authored in Visual Studio 2010 or Visual Studio 2012 will run on the cloud without requiring any modifications what so ever. Microsoft’s cloud test rig also supports API based testing, for example, if you are building a WPF application which consumes WCF services, you can write unit tests to invoke the WCF service, these tests can be run on the cloud test rig and loaded with ‘N’ concurrent users for performance testing. If you have your assets already hosted in the Azure and possibly in the same data centre as the Cloud test rig, your Azure app will not incur a usage cost because of the generated traffic since the traffic is coming from the same data centre. The licensing or pricing information on Microsoft’s cloud based Load test service is yet to be announced, but I would expect this to be priced attractively to match the market competition.   The only additional configuration required for running load tests on Microsoft Cloud based Load Tests service is to select the Test run location as Run tests using Visual Studio Team Foundation Service, How have I been using Microsoft’s Cloud based Load Test Service? I have been part of the Microsoft Cloud Based Load Test Service advisory council for the last 7 months. This gave the opportunity to see the product shape up from concept to working solution. I was also the first person outside of Microsoft to try this offering out. This gave me the opportunity to test real world application at various clients using the Microsoft Load Test Service and provide real world feedback to the Microsoft product team. One of the most recent systems I tested using the Load Test Service has been an insurance quote generation engine. This insurance quote generation engine is,   hosted in Windows Azure expected to get quote requests from across the globe expected to handle 5 Million quote requests in a day (not clear how this load will be distributed across the day) There was no way, I could simulate such kind of load from on premise without standing up additional hardware. But Microsoft’s Cloud based Load Test service allowed me to test my key performance testing scenarios, i.e. Simulate expected Load, Endurance Testing, Threshold Testing and Testing for Latency. Simulating expected load: approach to devising a load pattern My approach to devising a load test pattern has been to run the test scenario with 1 user to figure out the response time. Then work out how many users are required to reach the target load. So, for example, to invoke 1 quote from the quote engine software takes 0.5 seconds. Now if you do the math,   1 quote request by 1 user = 0.5 seconds   quotes generated by 1 user in 24 hour = 1 * (((2 * 60) * 60) * 24) = 172,800   quotes generated by 30 users in 24 hours = 172,800 * 30 =  5,184,000 This was a very simple example, if your application requires more concurrent users to test scenario’s such as caching, etc then you can devise your own load pattern, some examples of load test patterns can be found here.  Endurance Testing To test for endurance, I loaded the quote generation engine with an expected fixed user load and ran the test for very long duration such as over 48 hours and observed the affect of the long running test on the Azure infrastructure. Currently Microsoft Load Test service does not support metrics from the machine under test. I used Azure diagnostics to begin with, but later started using Cerebrata Azure Diagnostics Manager to capture the metrics of the machine under test. Threshold Testing To figure out how much user load the application could cope with before falling on its belly, I opted to step load the quote generation engine by incrementing user load with different variations of incremental user load per minute till the application crashed out and forced an IIS reset. Testing for Latency Currently the Microsoft Load Test service does not support generating geographically distributed load, I however, deployed the insurance quote generation engine in different Azure data centres and ran the same set of performance tests to measure for latency. Because I could compare load test results from different runs by exporting the results to excel (this feature is provided out of the box right from Visual Studio 2010) I could see the different in response times. More resources on Microsoft Cloud based Load Test Service A few important links to get you started, Download Visual Studio Ultimate 2013 Preview Getting started guide for load testing using Team Foundation Service Troubleshooting guide for FAQs and known issues Team Foundation Service forum for questions and support Detailed demo and presentation (link to Tech-Ed session recording) Detailed demo and presentation (link to Build session recording) There a few limits on the usage of Microsoft Cloud based Load Test service that you can read about here. If you have any feedback on Microsoft Cloud based Load Test service, feel free to share it with the product team via the Visual Studio User Voice forum. I hope you found this useful. Thank you for taking the time out and reading this blog post. If you enjoyed the post, remember to subscribe to http://feeds.feedburner.com/TarunArora. Stay tuned!

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  • What are the difference between: agent, actor, dataflow based programming?

    - by inf3rno
    What are the difference between the following terms? agent-based programming agent-based programming with microagents actor-based programming actor-based programming with lightweight actors dataflow based programming It is hard to find comparing articles and they are very similar. Afaik they have different constraints and they are implemented on a different abstraction level, but I need some reassurance...

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  • ASP.NET MVC - Html.DropDownList - Value not set via ViewData.Model

    - by chrisb
    Have just started playing with ASP.NET MVC and have stumbled over the following situation. It feels a lot like a bug but if its not, an explanation would be appreciated :) The View contains pretty basic stuff <%=Html.DropDownList("MyList", ViewData["MyListItems"] as SelectList)%> <%=Html.TextBox("MyTextBox")%> When not using a model, the value and selected item are set as expected: //works fine public ActionResult MyAction(){ ViewData["MyListItems"] = new SelectList(items, "Value", "Text"); //items is an ienumerable of {Value="XXX", Text="YYY"} ViewData["MyList"] = "XXX"; //set the selected item to be the one with value 'XXX' ViewData["MyTextBox"] = "ABC"; //sets textbox value to 'ABC' return View(); } But when trying to load via a model, the textbox has the value set as expected, but the dropdown doesnt get a selected item set. //doesnt work public ActionResult MyAction(){ ViewData["MyListItems"] = new SelectList(items, "Value", "Text"); //items is an ienumerable of {Value="XXX", Text="YYY"} var model = new { MyList = "XXX", //set the selected item to be the one with value 'XXX' MyTextBox = "ABC" //sets textbox value to 'ABC' } return View(model); } Any ideas? My current thoughts on it are that perhaps when using a model, we're restricted to setting the selected item on the SelectList constructor instead of using the viewdata (which works fine) and passing the selectlist in with the model - which would have the benefit of cleaning the code up a little - I'm just wondering why this method doesnt work.... Many thanks for any suggestions

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  • ASP.net MVC - Update Model on complex models

    - by ludicco
    Hi there, I'm struggling myself trying to get the contents of a form which is a complex model and then update the model with that complex model. My account model has many individuals [AcceptVerbs(HttpVerbs.Post)] public ActionResult OpenAnAccount(string area,[Bind(Exclude = "Id")]Account account, [Bind(Prefix="Account.Individuals")] EntitySet<Individual> individuals){ var db = new DB(); account.individuals = invdividuals; db.Accounts.InsertOnSubmit(account); db.SubmitChanges(); } So it works nicely for adding new Records, but not for update them like: [AcceptVerbs(HttpVerbs.Post)] public ActionResult OpenAnAccount(string area,[Bind(Exclude = "Id")]Account account, [Bind(Prefix="Account.Individuals")] EntitySet<Individual> individuals){ var db = new DB(); var record = db.Accounts.Single(a => a.Reference == area); account.individuals = invdividuals; try{ UpdateModel(record, account); // I can't convert account ToValueProvider() db.SubmitChanges(); } catch{ return ... //Error Message } } My problem is being how to use UpdateModel with the account model since it's not a FormCollection. How can I convert it? How can I use ToValueProvider with a complex model? I hope I was clear enough Thanks a lot :)

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  • Django model operating on a queryset

    - by jmoz
    I'm new to Django and somewhat to Python as well. I'm trying to find the idiomatic way to loop over a queryset and set a variable on each model. Basically my model depends on a value from an api, and a model method must multiply one of it's attribs by this api value to get an up-to-date correct value. At the moment I am doing it in the view and it works, but I'm not sure it's the correct way to achieve what I want. I have to replicate this looping elsewhere. Is there a way I can encapsulate the looping logic into a queryset method so it can be used in multiple places? I have this atm (I am using django-rest-framework): class FooViewSet(viewsets.ModelViewSet): model = Foo serializer_class = FooSerializer bar = # some call to an api def get_queryset(self): # Dynamically set the bar variable on each instance! foos = Foo.objects.filter(baz__pk=1).order_by('date') for item in foos: item.needs_bar = self.bar return items I would think something like so would be better: def get_queryset(self): bar = # some call to an api # Dynamically set the bar variable on each instance! return Foo.objects.filter(baz__pk=1).order_by('date').set_bar(bar) I'm thinking the api hit should be in the controller and then injected to instances of the model, but I'm not sure how you do this. I've been looking around querysets and managers but still can't figure it out nor decided if it's the best method to achieve what I want. Can anyone suggest the correct way to model this with django? Thanks.

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  • CakePHP belongsTo relationship with a variable 'model' field.

    - by gomezuk
    I've got a problem with a belongsTo relationship in CakePHP. I've got an "Action" model that uses the "actions" table and belongs to one of two other models, either "Transaction" or "Tag". The idea being that whenever a user completes a transaction or adds a tag, the action model is created to keep a log of it. I've got that part working, whenever a Transaction or Tag is saved, the aftersave() method also adds an Action record. The problem comes when I try to do a find('all') on the Action model, the related Transaction or Tag record is not being returned. actions: id model model_id created I thought I could use the "conditions" parameter in the belongsTo relationship like this: <?php class Action extends AppModel { var $name = 'Action'; var $actsAs = array('Containable'); var $belongsTo = array( 'Transaction' => array( 'foreignKey' => 'model_id', 'conditions' => array("Action.model"=>"Transaction") ), 'User' => array( 'fields' => array('User.username') ), 'Recommendation' => array( 'conditions' => array("Action.model"=>"Recommendation"), 'foreignKey' => 'model_id' ) ); } ?> But that doesn't work. Am I missing something here, are my relationships wrong (I suspect so)? After Googling this problem I cam across something called Polymorphic Behaviour but I'm not sure this will help me.

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  • JSON Serialization of a Django inherited model

    - by Simon Morris
    Hello, I have the following Django models class ConfigurationItem(models.Model): path = models.CharField('Path', max_length=1024) name = models.CharField('Name', max_length=1024, blank=True) description = models.CharField('Description', max_length=1024, blank=True) active = models.BooleanField('Active', default=True) is_leaf = models.BooleanField('Is a Leaf item', default=True) class Location(ConfigurationItem): address = models.CharField(max_length=1024, blank=True) phoneNumber = models.CharField(max_length=255, blank=True) url = models.URLField(blank=True) read_acl = models.ManyToManyField(Group, default=None) write_acl = models.ManyToManyField(Group, default=None) alert_group= models.EmailField(blank=True) The full model file is here if it helps. You can see that Company is a child class of ConfigurationItem. I'm trying to use JSON serialization using either the django.core.serializers.serializer or the WadofStuff serializer. Both serializers give me the same problem... >>> from cmdb.models import * >>> from django.core import serializers >>> serializers.serialize('json', [ ConfigurationItem.objects.get(id=7)]) '[{"pk": 7, "model": "cmdb.configurationitem", "fields": {"is_leaf": true, "extension_attribute_10": "", "name": "", "date_modified": "2010-05-19 14:42:53", "extension_attribute_11": false, "extension_attribute_5": "", "extension_attribute_2": "", "extension_attribute_3": "", "extension_attribute_1": "", "extension_attribute_6": "", "extension_attribute_7": "", "extension_attribute_4": "", "date_created": "2010-05-19 14:42:53", "active": true, "path": "/Locations/London", "extension_attribute_8": "", "extension_attribute_9": "", "description": ""}}]' >>> serializers.serialize('json', [ Location.objects.get(id=7)]) '[{"pk": 7, "model": "cmdb.location", "fields": {"write_acl": [], "url": "", "phoneNumber": "", "address": "", "read_acl": [], "alert_group": ""}}]' >>> The problem is that serializing the Company model only gives me the fields directly associated with that model, not the fields from it's parent object. Is there a way of altering this behaviour or should I be looking at building a dictionary of objects and using simplejson to format the output? Thanks in advance ~sm

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  • About Data Objects and DAO Design when using Hibernate

    - by X. Ma
    I'm hesitating between two designs of a database project using Hibernate. Design #1. (1) Create a general data provider interface, including a set of DAO interfaces and general data container classes. It hides the underneath implementation. A data provider implementation could access data in database, or an XML file, or a service, or something else. The user of a data provider does not to know about it. (2) Create a database library with Hibernate. This library implements the data provider interface in (1). The bad thing about Design #1 is that in order to hide the implementation details, I need to create two sets of data container classes. One in the general data provider interface - let's call them DPI-Objects, the other set is used in the database library, exclusively for entity/attribute mapping in Hibernate - let's call them H-Objects. In the DAO implementation, I need to read data from database to create H-Objects (via Hibernate) and then convert H-Objects into DPI-Objects. Design #2. Do not create a general data provider interface. Expose H-Objects directly to components that use the database lib. So the user of the database library needs to be aware of Hibernate. I like design #1 more, but I don't want to create two sets of data container classes. Is that the right way to hide H-Objects and other Hibernate implementation details from the user who uses the database-based data provider? Are there any drawbacks of Design #2? I will not implement other data provider in the new future, so should I just forget about the data provider interface and use Design #2? What do you think about this? Thanks for your time!

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  • Implementing Model-level caching

    - by Byron
    I was posting some comments in a related question about MVC caching and some questions about actual implementation came up. How does one implement a Model-level cache that works transparently without the developer needing to manually cache, yet still remains efficient? I would keep my caching responsibilities firmly within the model. It is none of the controller's or view's business where the model is getting data. All they care about is that when data is requested, data is provided - this is how the MVC paradigm is supposed to work. (Source: Post by Jarrod) The reason I am skeptical is because caching should usually not be done unless there is a real need, and shouldn't be done for things like search results. So somehow the Model itself has to know whether or not the SELECT statement being issued to it worthy of being cached. Wouldn't the Model have to be astronomically smart, and/or store statistics of what is being most often queried over a long period of time in order to accurately make a decision? And wouldn't the overhead of all this make the caching useless anyway? Also, how would you uniquely identify a query from another query (or more accurately, a resultset from another resultset)? What about if you're using prepared statements, with only the parameters changing according to user input? Another poster said this: I would suggest using the md5 hash of your query combined with a serialized version of your input arguments. This would require twice the number of serialization options. I was under the impression that serialization was quite expensive, and for large inputs this might be even worse than just re-querying. And is the minuscule chance of collision worth worrying about? Conceptually, caching in the Model seems like a good idea to me, but it seems in practicality the developer should have direct control over caching and write it into the controller. Thoughts/ideas? Edit: I'm using PHP and MySQL if that helps to narrow your focus.

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  • MVC design in Cocoa - are all 3 always necessary? Also: naming conventions, where to put Controller

    - by Nektarios
    I'm new to MVC although I've read a lot of papers and information on the web. I know it's somewhat ambiguous and there are many different interpretations of MVC patterns.. but the differences seem somewhat minimal My main question is - are M, V, and C always going to be necessary to be doing this right? I haven't seen anyone address this in anything I've read. Examples (I'm working in Cocoa/Obj-c although that shouldn't much matter).. 1) If I have a simple image on my GUI, or a text entry field that is just for a user's convenience and isn't saved or modified, these both would be V (view) but there's no M (no data and no domain processing going on), and no C to bridge them. So I just have some aspects that are "V" - seems fine 2) I have 2 different and visible windows that each have a button on them labeled as "ACTIVATE FOO" - when a user clicks the button on either, both buttons press in and change to say "DEACTIVATE FOO" and a third window appears with label "FOO". Clicking the button again will change the button on both windows to "ACTIVATE FOO" and will remove the third "FOO" window. In this case, my V consists of the buttons on both windows, and I guess also the third window (maybe all 3 windows). I definitely have a C, my Controller object will know about these buttons and windows and will get their clicks and hold generic states regarding windows and buttons. However, whether I have 1 button or 10 button, my window is called "FOO" or my window is called "BAR", this doesn't matter. There's no domain knowledge or data here - just control of views. So in this example, I really have "V" and "C" but no "M" - is that ok? 3) Final example, which I am running in to the most. I have a text entry field as my View. When I enter text in this, say a number representing gravity, I keep it in a Model that may do things like compute physics of a ball while taking in to account my gravity parameter. Here I have a V and an M, but I don't understand why I would need to add a C - a controller would just accept the signals from the View and pass it along to the Model, and vice versa. Being as the C is just a pure passthrough, it's really "junk" code and isn't making things any more reusable in my opinion. In most situations, when something changes I will need to change the C and M both in nearly identical ways. I realize it's probably an MVC beginner's mistake to think most situations call for only V and M.. leads me in to next subject 4) In Cocoa / Xcode / IB, I guess my Controllers should always be an instantiated object in IB? That is, I lay all of my "V" components in IB, and for each collection of View objects (things that are related) I should have an instantiated Controller? And then perhaps my Models should NOT be found in IB, and instead only found as classes in Xcode that tie in with Controller code found there. Is this accurate? This could explain why you'd have a Controller that is not really adding value - because you are keeping consistent.. 5) What about naming these things - for my above example about FOO / BAR maybe something that ends in Controller would be the C, like FancyWindowOpeningController, etc? And for models - should I suffix them with like GravityBallPhysicsModel etc, or should I just name those whatever I like? I haven't seen enough code to know what's out there in the wild and I want to get on the right track early on Thank you in advance for setting me straight or letting me know I'm on the right track. I feel like I'm starting to get it and most of what I say here makes sense, but validation of my guessing would help me feel confident..

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  • A good data model for finding a user's favorite stories

    - by wings
    Original Design Here's how I originally had my Models set up: class UserData(db.Model): user = db.UserProperty() favorites = db.ListProperty(db.Key) # list of story keys # ... class Story(db.Model): title = db.StringProperty() # ... On every page that displayed a story I would query UserData for the current user: user_data = UserData.all().filter('user =' users.get_current_user()).get() story_is_favorited = (story in user_data.favorites) New Design After watching this talk: Google I/O 2009 - Scalable, Complex Apps on App Engine, I wondered if I could set things up more efficiently. class FavoriteIndex(db.Model): favorited_by = db.StringListProperty() The Story Model is the same, but I got rid of the UserData Model. Each instance of the new FavoriteIndex Model has a Story instance as a parent. And each FavoriteIndex stores a list of user id's in it's favorited_by property. If I want to find all of the stories that have been favorited by a certain user: index_keys = FavoriteIndex.all(keys_only=True).filter('favorited_by =', users.get_current_user().user_id()) story_keys = [k.parent() for k in index_keys] stories = db.get(story_keys) This approach avoids the serialization/deserialization that's otherwise associated with the ListProperty. Efficiency vs Simplicity I'm not sure how efficient the new design is, especially after a user decides to favorite 300 stories, but here's why I like it: A favorited story is associated with a user, not with her user data On a page where I display a story, it's pretty easy to ask the story if it's been favorited (without calling up a separate entity filled with user data). fav_index = FavoriteIndex.all().ancestor(story).get() fav_of_current_user = users.get_current_user().user_id() in fav_index.favorited_by It's also easy to get a list of all the users who have favorited a story (using the method in #2) Is there an easier way? Please help. How is this kind of thing normally done?

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  • Complicated .NET factory design

    - by Tom W
    Hello SO; I'm planning to ask a fairly elaborate question that is also something of a musing here, so bear with me... I'm trying to design a factory implementation for a simulation application. The simulation will consist of different sorts of entities i.e. it is not a homogenous simulation in any respect. As a result, there will be numerous very different concrete implementations and only the very general properties will be abstracted at the top level. What I'd like to be able to do is create new simulation entities by calling a method on the model with a series of named arguments representing the parameters of the entity, and have the model infer what type of object is being described by the inbound parameters (from the names of the parameters and potentially the sequence they occur in) and call a factory method on the appropriate derived class. For example, if I pass the model a pair of parameters (Param1=5000, Param2="Bacon") I would like it to infer that the names Param1 and Param2 'belong' to the class "Blob1" and call a shared function "getBlob1" with named parameters Param1:=5000, Param2:="Bacon" whereas if I pass the model (Param1=5000, Param3=50) it would call a similar factory method for Blob2; because Param1 and Param3 in that order 'belong' to Blob2. I foresee several issues to resolve: Whether or not I can reflect on the available types with string parameter names and how to do this if it's possible Whether or not there's a neat way of doing the appropriate constructor inference from the combinatoric properties of the argument list or whether I'm going to have to bodge something to do it 'by hand'. If possible I'd like the model class to be able to accept parameters as parameters rather than as some collection of keys and values, which would require the model to expose a large number of parametrised methods at runtime without me having to code them explicitly - presumably one for every factory method available in the relevant namespace. What I'm really asking is how you'd go about implementing such a system, rather than whether or not it's fundamentally possible. I don't have the foresight or experience with .NET reflection to be able to figure out a way by myself. Hopefully this will prove an informative discussion.

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  • How to Correct & Improve the Design of this Code?

    - by DaveDev
    HI Guys, I've been working on a little experiement to see if I could create a helper method to serialize any of my types to any type of HTML tag I specify. I'm getting a NullReferenceException when _writer = _viewContext.Writer; is called in protected virtual void Dispose(bool disposing) {/*...*/} I think I'm at a point where it almost works (I've gotten other implementations to work) and I was wondering if somebody could point out what I'm doing wrong? Also, I'd be interested in hearing suggestions on how I could improve the design? So basically, I have this code that will generate a Select box with a number of options: // the idea is I can use one method to create any complete tag of any type // and put whatever I want in the content area <% using (Html.GenerateTag<SelectTag>(Model, new { href = Url.Action("ActionName") })) { %> <%foreach (var fund in Model.Funds) {%> <% using (Html.GenerateTag<OptionTag>(fund)) { %> <%= fund.Name %> <% } %> <% } %> <% } %> This Html.GenerateTag helper is defined as: public static MMTag GenerateTag<T>(this HtmlHelper htmlHelper, object elementData, object attributes) where T : MMTag { return (T)Activator.CreateInstance(typeof(T), htmlHelper.ViewContext, elementData, attributes); } Depending on the type of T it'll create one of the types defined below, public class HtmlTypeBase : MMTag { public HtmlTypeBase() { } public HtmlTypeBase(ViewContext viewContext, params object[] elementData) { base._viewContext = viewContext; base.MergeDataToTag(viewContext, elementData); } } public class SelectTag : HtmlTypeBase { public SelectTag(ViewContext viewContext, params object[] elementData) { base._tag = new TagBuilder("select"); //base.MergeDataToTag(viewContext, elementData); } } public class OptionTag : HtmlTypeBase { public OptionTag(ViewContext viewContext, params object[] elementData) { base._tag = new TagBuilder("option"); //base.MergeDataToTag(viewContext, _elementData); } } public class AnchorTag : HtmlTypeBase { public AnchorTag(ViewContext viewContext, params object[] elementData) { base._tag = new TagBuilder("a"); //base.MergeDataToTag(viewContext, elementData); } } all of these types (anchor, select, option) inherit from HtmlTypeBase, which is intended to perform base.MergeDataToTag(viewContext, elementData);. This doesn't happen though. It works if I uncomment the MergeDataToTag methods in the derived classes, but I don't want to repeat that same code for every derived class I create. This is the definition for MMTag: public class MMTag : IDisposable { internal bool _disposed; internal ViewContext _viewContext; internal TextWriter _writer; internal TagBuilder _tag; internal object[] _elementData; public MMTag() {} public MMTag(ViewContext viewContext, params object[] elementData) { } public void Dispose() { Dispose(true /* disposing */); GC.SuppressFinalize(this); } protected virtual void Dispose(bool disposing) { if (!_disposed) { _disposed = true; _writer = _viewContext.Writer; _writer.Write(_tag.ToString(TagRenderMode.EndTag)); } } protected void MergeDataToTag(ViewContext viewContext, object[] elementData) { Type elementDataType = elementData[0].GetType(); foreach (PropertyInfo prop in elementDataType.GetProperties()) { if (prop.PropertyType.IsPrimitive || prop.PropertyType == typeof(Decimal) || prop.PropertyType == typeof(String)) { object propValue = prop.GetValue(elementData[0], null); string stringValue = propValue != null ? propValue.ToString() : String.Empty; _tag.Attributes.Add(prop.Name, stringValue); } } var dic = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase); var attributes = elementData[1]; if (attributes != null) { foreach (PropertyDescriptor descriptor in TypeDescriptor.GetProperties(attributes)) { object value = descriptor.GetValue(attributes); dic.Add(descriptor.Name, value); } } _tag.MergeAttributes<string, object>(dic); _viewContext = viewContext; _viewContext.Writer.Write(_tag.ToString(TagRenderMode.StartTag)); } } Thanks Dave

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  • Two references to the same domain/entity model

    - by Sbossb
    Problem I want to save the attributes of a model that have changed when a user edits them. Here's what I want to do ... Retrieve edited view model Get domain model and map back updated value Call the update method on repository Get the "old" domain model and compare values of the fields Store the changed values (in JSON) into a table However I am having trouble with step number 4. It seems that the Entity Framework doesn't want to hit the database again to get the model with the old values. It just returns the same entity I have. Attempted Solutions I have tried using the Find() and the SingleOrDefault() methods, but they just return the model I currently have. Example Code private string ArchiveChanges(T updatedEntity) { //Here is the problem! //oldEntity is the same as updatedEntity T oldEntity = DbSet.SingleOrDefault(x => x.ID == updatedEntity.ID); Dictionary<string, object> changed = new Dictionary<string, object>(); foreach (var propertyInfo in typeof(T).GetProperties()) { var property = typeof(T).GetProperty(propertyInfo.Name); //Get the old value and the new value from the models var newValue = property.GetValue(updatedEntity, null); var oldValue = property.GetValue(oldEntity, null); //Check to see if the values are equal if (!object.Equals(newValue, oldValue)) { //Values have changed ... log it changed.Add(propertyInfo.Name, newValue); } } var ser = new System.Web.Script.Serialization.JavaScriptSerializer(); return ser.Serialize(changed); } public override void Update(T entityToUpdate) { //Do something with this string json = ArchiveChanges(entityToUpdate); entityToUpdate.AuditInfo.Updated = DateTime.Now; entityToUpdate.AuditInfo.UpdatedBy = Thread.CurrentPrincipal.Identity.Name; base.Update(entityToUpdate); }

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  • Oracle Insurance Gets Innovative with Insurance Business Intelligence

    - by nicole.bruns(at)oracle.com
    Oracle Insurance announced yesterday the availability of Oracle Insurance Insight 7.0, an insurance-specific data warehouse and business intelligence (BI) system that transforms the traditional approach to BI by involving business users in the creation and maintenance."Rapid access to business intelligence is essential to compete and thrive in today's insurance industry," said Srini Venkatasantham, vice president, Product Strategy, Oracle Insurance. "The adaptive data modeling approach of Oracle Insurance Insight 7.0, combined with the insurance-specific data model, offers global insurance companies a faster, easier way to get the intelligence they need to make better-informed business decisions." New Features in Oracle Insurance 7.0 include:"Adaptive Data Modeling" via the new warehouse palette: Gives business users the power to configure lines of business via an easy-to-use warehouse palette tool. Oracle Insurance Insight then automatically creates data warehouse elements - such as line-specific database structures and extract-transform-load (ETL) processes -speeding up time-to-value for BI initiatives. Out-of-the-box insurance models or create-from-scratch option: Includes pre-built content and interfaces for six Property and Casualty (P&C) lines. Additionally, insurers can use the warehouse palette to deploy any and all P&C or General Insurance lines of business from scratch, helping insurers support operations in any country.Leverages Oracle technologies: In addition to Oracle Business Intelligence Enterprise Edition, the solution includes Oracle Database 11g as well as Oracle Data Integrator Enterprise Edition 11g, which delivers Extract, Load and Transform (E-L-T) architecture and eliminates the need for a separate transformation server. Additionally, the expanded Oracle technology infrastructure enables support for Oracle Exadata. Martina Conlon, a Principal with Novarica's Insurance practice, and author of Business Intelligence in Insurance: Current State, Challenges, and Expectations says, "The need for continued investment by insurers in business intelligence capabilities is widely understood, and the industry is acting. Arming the business intelligence implementation with predefined insurance specific content, and flexible and configurable technology will get these projects up and running faster."Learn moreTo see a demo of the Oracle Insurance Insight system, click hereTo read the press announcement, click here

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