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  • How to export EclipseLink objects to XML

    - by Raven
    Hi, is there an easy approach to store my model, which I use with EclipseLink, in XML files? I want to implement an export functionality in my program and I was wondering if this can be done with eclipselink or with any other framework. Thanks

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  • Returning modified data to a template

    - by Duncan
    I need to amend QuerySet data when i return it to a template. for example, model.objects.all() returns a date (with other fields), but i also want to return the number of days since that date has passed. This is so that in the template, i can say "you last logged in 4 days ago". What is the best way to do this?

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  • SQL Server JOIN with optional NULL values

    - by Paul McLoughlin
    Imagine that we have two tables as follows: Trades ( TradeRef INT NOT NULL, TradeStatus INT NOT NULL, Broker INT NOT NULL, Country VARCHAR(3) NOT NULL ) CTMBroker ( Broker INT NOT NULL, Country VARCHAR(3) NULL ) (These have been simplified for the purpose of this example). Now, if we wish to join these two tables on the Broker column, and if a country exists in the CTMBroker table on the Country, we have the following two choices: SELECT T.TradeRef,T.TradeStatus FROM Trades AS T JOIN CTMBroker AS B ON B.Broker=T.Broker AND ISNULL(B.Country, T.Country) = T.Country or SELECT T.TradeRef,T.TradeStatus FROM Trades AS T JOIN CTMBroker AS B ON B.Broker=T.Broker AND (B.COUNTRY=T.Country OR B.Country IS NULL) These are both logically equivalent, however in this specific circumstance for our database (SQL Server 2008, SP1) two different execution plans are produced for these two queries with the second version significantly outperforming the first version in terms of both time and logical reads. My question really is as follows: as a general rule would (2) be preferred to (1), or does this just happen to be exploiting some particular idiosyncracy of the optimiser in 2008 SP1 (that could therefore change with future versions of SQL Server).

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  • Why is C++ backward compatible with C ? Why isn't there some "pure" C++ language ?

    - by gokoon
    C and C++ are different languages, blababla we know that. But if those language are different, why is it still possible to use function like malloc or free ? I'm sure there are all sort of dusty things C++ has because of C, but since C++ is another language, why not remove those things to make it a little less bloat and more clean and clear ? Is it because it allows programmers to work without the OO model or because some compilers doesn't support high-level abstract features of C++ ?

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  • WM_SYSCOMMAND oddities

    - by Andreas Rejbrand
    An application recieves the WM_SYSCOMMAND message when the user selects a menu item command on the system menu, and so wParam can be SC_CLOSE, SC_CONTEXTHELP, SC_MAXIMIZE, SC_MINIMIZE, SC_RESTORE etc. That's logical. But one can also send the WM_SYSCOMMAND message to send commands to the Windows Shell. For instance, one can display the start menu (SC_TASKLIST), activate the screen saver (SC_SCREENSAVE), and turn off the monitor (SC_MONITORPOWER). This does not make sense, does it? What does this have to do with the application's system menu? This is more of a "system command", i.e. more of a completely other interpretation of the name "WM_SYSCOMMAND" of the message. It's like the message is used to send command requests to the system. Why is this message used for two seemingly entirely different things, and what thing does the name "SYSCOMMAND" refer to (command on the system menu, or command of the operating system)?

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  • how to bind association in RoR

    - by ashok
    I have two tables, AppTemplate and AppTemplateMeta AppTemplate table has column id, MetaID, name etc. I have associated these two model like this class AppTemplate < ActiveRecord::Base set_table_name 'AppTemplate' belongs_to :app_template_meta, :class_name => "AppTemplateMeta", :foreign_key => 'MetaID' end If we fetch data using AppTemplate.all, I want associated meta details also. But currently it's not returning associated meta details. It just returns AppTemplate details. any guys can help me for this

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  • UML tool similar to USE

    - by llazzaro
    Hello, To "simulate" instances from class diagrams I am using USE But I find very frustating to create instances. I am looking for similar tools like this one. I really like USE, but GUI is painfull. I think, that USE is pretty cool to learn how the model "works". Do you know similar tools like this one?

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  • Authlogic's current_user object in models

    - by jriff
    Hi all! I need to know the ID of the current user in a model: def after_save desc, points=nil, nil if answer_index == daily_question.correct_answer_index desc = I18n.t('daily_question.point_log.description.correct') points=daily_question.points else desc = I18n.t('daily_question.point_log.description.incorrect') end current_user.give_points(:description => desc, :points => points ) end But I guess that is not how it is done? Regards, Jacob

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  • Is there an ActiveRecord equivalent to using a nested subquery i.e. ... where NOT IN(select...) ?

    - by Snorkpete
    I have 3 models: Category, Account, and SubAccount The relations are: Accounts has_many :sub_accounts Categories has_many :sub_accounts I wanted to get a list of all Categories that are not used by a given account. My method in the Category model currently looks like: class Category < ActiveRecord::Base def self.not_used_by(account) Category.find_by_sql("select * from categories where id not in(select category_id from sub_accounts where account_id = #{account.id})") end end My question is, is there a cleaner alternative than using SQL? NB. I am currently using Rails 3(beta)

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  • Is it possible to mix a named pipe with select in perl?

    - by Haiyuan Zhang
    I need to write a daemon that supposed to have one TCP socket and one named pipe. Usually if I need to implement a multi IO server with "pure" sockets, the select based multi-IO model is always the one I will choose. so does anyone of you have ever used named pipe in select or you can just tell me it is impossible. thanks in advance.

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  • Modifying an observable collection bound to a ListBox

    - by Rohit Kandhal
    I've a collection in viewmodel binded to listbox. I want to hide a particular type from the collection. Here is the code: public ObservableCollection [YZModeModelView] YZModeModelView { return this.XModelVIew.YZModelViewCollection; } I want to a particular type of model view's from YZModelViewCollection. eg. ModelView's with property abc set to null. Any suggestions ...

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  • primary key datatype in sql server database

    - by ooo
    i see after installing the asp.net membership tables, they use the data type "uniqueidentifier" for all of the primary key fields. I have been using "int" data type and doing increment by one on inserts. Is there any particular benefits to using the uniqueIdentifier data type compared to my current model of using int and auto increments on new inserts ?

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  • Error for Minitab program (statistics)

    - by user216428
    I have a problem with Minitab (a statistics program). When I enter my general model and want to see the results, the program warns me: too few arguments or space missing. Everything seems true, and I can't determine where the problem is. Could anyone help me on this subject?

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  • asp.net mvc2 - update list of objects

    - by ile
    I want to display list of objects from database, and on the same page have option to edit them. When submitting, I'd like to submit changes to all of them. I found this link: http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx and http://www.hanselman.com/blog/ASPNETWireFormatForModelBindingToArraysListsCollectionsDictionaries.aspx but there is no description how to handle posted data in controller. Thanks in advance!

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  • Explain Entity Framework 4's connection strings

    - by metanaito
    I created an Entity Framework file. My database is called MyDB. My Entity Framework file is MyDB.edmx and I used an existing connection string (MyDBConnectionString) to generate the edmx model. It created two more connection strings: MyDBEntities MyDBContainer What are these for? They look exactly the same and both have the information from my old connection string. Do I still need my old connection string?

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  • PropertyChanged Event of ObservableCollection

    - by developer
    Hi All, I have a observable collection of viewmodel objects. How can I subscribe to the Property Changed event of each view model in my collection as they are created and track which ones have been changed, so that I can updated them to my database. List<DomainObject> objectsToSave = new List<DomainObject>(); foreach (Test val in dirtyObjs) { objectsToSave.AddRange(val.GetObjectsToSave()); } //DB changes bool saveSucceeded = DataServices.SaveMultiple(objectsToSave);

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  • Unit Testing VS 2008 Using Excel

    - by David
    When using Excel (2003) to provide data for my unit tests it seems to think that when a cell has TRUE / FALSE value that it is null when there has been no preceding cell values e.g. if (TestContext.DataRow["SatisfactionExtremelySatisfied"] != DBNull.Value) model.SatisfactionExtremelySatisfied = (bool)TestContext.DataRow ["SatisfactionExtremelySatisfied"]; Sample Excel Data DataRow SatisfactionExtremelySatisfied 0 1 2 TRUE 3 TRUE When reading the test data using OLEDB the cells with TRUE hold no value but when the preceding cells have the value FALSE entered it correctly gets the values TRUE. Am I missing something?

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  • Should I learn Haskell or F# if I already know OCaml?

    - by Unknown
    I am wondering if I should continue to learn OCaml or switch to F# or Haskell. Here are the criteria I am most interested in: Longevity Which language will last longer? I don't want to learn something that might be abandoned in a couple years by users and developers. Will Inria, Microsoft, University of Glasgow continue to support their respective compilers for the long run? Practicality Articles like this make me afraid to use Haskell. A hash table is the best structure for fast retrieval. Haskell proponents in there suggest using Data.Map which is a binary tree. I don't like being tied to a bulky .NET framework unless the benefits are large. I want to be able to develop more than just parsers and math programs. Well Designed I like my languages to be consistent. Please support your opinion with logical arguments and citations from articles. Thank you.

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  • Cocoa's newbie question: is it possible to bind a NSTableView's selection to another tableview's selection?

    - by cocoaOverloaded
    http://img651.imageshack.us/img651/6999/modelsf.jpg Let'say, I've 2 entities in the Core Data's Model file, one being all "transactions" ever done by X company. The "transactions" entity has among other properties, a "DATE" property and a to-one relationship "COMPANY"(specifying the company with which X company has done that particular transaction). The other entity:"companies" of course contains all the companies' info ,with which X company has done transaction. The "companies" entity has a to-many relationships "TRANSACTIONS" which is an inverse relationship to "transactions" entity's "COMPANY" relationship. So within IB, I created a NSTableView(with its own NSArrayController) showing all the transactions on a particular Date (with the help of NSPredicate). Then I create another table view showing the to-many relationship "TRANSACTIONS" of the company of the selected transaction in the first table view(which shows transactions on a particular date). The 2nd table view's NSArrayController binding is like this: ** bind to: "name of the first tableview's controller", Controller Key: selection, Model Key Path:COMPANY.TRANSACTIONS(the to-many relationship in the "companies" entity)** Everythings work fine up to this moment, the 2nd tableview shows all the transactions X company has done with the company of the selected transactions in the 1st table view. But I have a group of textfields showing details of a particular transactions. Binding the these textfields with the controller of the 1st table view(the one showing transactions on a particular date) is pretty straightforward. But what I want to do are: 1/ Look up the transactions on a particular date in the first table view, select any one of them 2/ Then, check all previous transactions of the company of that transaction( selected in the first table view) from the 2nd table view 3/ Select any previous transactions and check the details of the transaction from that group of textfields So naturally I should have bind the textfields' gp to the 2nd table view's controller. But I found the default selected row in the 2nd table view(the one show all previous transactions of a company) wasn't the transaction I've selected in the 1st tableView for a particular date. Of course, i can manually select that transaction in the 2nd table view again.... So I just want to know if it's possible to have the 2nd table view automatically select the transaction according to the transaction I've selected in the 1st table view thr binding?? After hours of googling, I solved the problem by implementing the tableview Delegate protocol: - (void)tableViewSelectionDidChange:(NSNotification *)aNotification { if (["nameOf1stTableView" selectedRow] > -1) { NSArray *objsArray = ["nameOf2ndTableView'sController" arrangedObjects]; for (id obj in objsArray) { if ([[obj valueForKey:@"DATE"] isEqualToDate: ["nameOf1stTableView'sController".selection valueForKey:@"DATE"]]) { ["nameOf2ndTableView" selectRowIndexes:[NSIndexSet indexSetWithIndex:[objsArray indexOfObject:obj]] byExtendingSelection:NO]; } } } } But,this just look too cumbersome... can it be done with binding alone? Thanks in Advance,

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  • Where to reopen a class in RoR

    - by Jeriko
    I'm attempting to reopen the String class in rails and add a bunch more methods for my app to use. Writing the code isn't a problem - my question is rather about where this code should go. It doesn't make sense to me to reopen a class inside a different model file, because it really has nothing to do with any of the models specifically. I thought perhaps somewhere in config or lib would make sense, but I'm not particularly well versed with RoR yet. To summarize, where would be the most logical place to define class-modifying code?

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