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  • Implementing 1 to n mapping for ORM c++

    - by karan
    I am writing a project where I need to implement a stripped down version of an ORM solution in C++. I am struck in implementing 1-n relationships for the same. For instance, if the following are the classes: class A { ... } class B { ... std::list<A> _a_list; ... } I have provided load/save methods for loading/saving to the db. Now, if I take the case of B and the following workflow: 1 entry from _a_list is removed 1 entry from _a_list is modified 1 entry is added to _a_list Now, I need to update the db using something like "b.save()". So, what would be the best way to save the changes, i.e, identify the additions, deletions and updates to _a_list.

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  • How do I create multiple submit buttons for the same form in Rails?

    - by Angela
    I need to have multiple submit buttons. I have a form which creates an instance of Contact_Call. One button creates it as normal. The other button creates it but needs to have a different :attribute value from the default, and it also needs to set the attribute on a different, but related model used in the controller. How do I do that? I can't change the route, so is there a way to send a different variable that gets picked up by [:params]? And if I do then, what do I do in the controller, set up a case statement?

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  • Setting package-wide variables during python setup.py install

    - by Morgoth
    Is there a way that when a user types python setup.py install to install a Python package, setup.py can be made to set specific variables at the base of the pacakge? A common example would be to basically set mypackage.__revision__ to be the svn revision of the checkout if one is working from svn. Another example case would be if the user can choose a global option, so that the option mypackage.__option__ be set according to a flag passed to setup.py, e.g. python setup.py install --set-flag=10 Then when using the package, mypackage.__option__ would equal 10.

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  • What is the Software Development Lifecycle?

    - by j-t-s
    Our investor wants a SDLC. I've never written one before, and I don't have enough time to go and buy a book, or spend much time learning about them. From what I've been told about them, they consist of requirements (what needs to be done), and a list is done. Is this correct? Update: I have found this article which really helps to explain things in simple terms and very quickly. Not that I think an SDLC should be done quickly. In my case, I have no other option.

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  • How to build the ViewModel in MVVM not to violate the Single Responsibility Principle?

    - by Przemek
    Robert Martin says: "There should never be more than one reason for a class to change". Let's consider the ViewModel class which is bound to a View. It is possible (or even probable) that the ViewModel consists of properties that are not really related to each other. For small views the ViewModel may be quite coherent, but while the application gets more complex the ViewModel will expose data that will be subject to change for different and unrelated reasons. Should we worry about the SRP principle in the case of ViewModel class or not?

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  • Importing Classes Within a Module

    - by CodeJoust
    Currently, I have a parser with multiple classes that work together. For Instance: TreeParser creates multiple Product and Reactant modules which in turn create multiple Element classes. The TreeParser is called by a render method within the same module, which is called from the importer. Currently, using the class name in the imported module file works only if the file calling the module contains from module_name import *, so the classes are imported into the main namespace. Finally, if the package has dependencies (such as re and another another module within the same folder), where is the best place to require those modules? Within the __init__.py file or within the module itself? I don't really want to add the module name in front of every call to the class, in case I do call import *, however, is it possible to use a variable name of the current module to call the class, or use a workaround in the __init__.py file? I'm probably used to the ruby require '' method instead of python's module system.

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  • Designing a frontend/backend architecture

    - by wrp
    What are some good information sources on designing programs with a client/server architecture? This is for development of a desktop application, not a Web service. The only books I have found on client/server apps deal with the case of a thin client connecting to a remote database. Two good examples of what I mean are Mathematica and SuperCollider. I'm looking for platform- and language-agnostic discussion of the issues in developing a frontend/backend system. Especially useful topics would be allocation of responsibilities and options for message passing.

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  • How can I get the element in which highlighted text is in?

    - by Koes Bong
    I am trying to learn how to write a bookmarklet where I can highlight some text, click on the bookmarklet and have it tell me what got highlighted. I can get that far, but next I want to know what element that text is in. For example: <div id="some-id">to be highlighted</div> The bookmarklet code: javascript:(function(){alert(window.getSelection();})() If I highlight the text "to be highlighted" and then click on the bookmarklet, it will alert the text. But how can I get the element in which the text is in, in this case the element after that? So the flow is: highlight text, click bookmarklet, bookmarklet tells you what you highlighted and the element it's in. Thanks!

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  • Useful design patterns when dealing with spring 3 controllers

    - by Mat Banik
    Recently I was overlooking my controllers and they are bit of mess. I'd like to organize they way I set returning views Do more elegant mesageSource massaging back to the users and account for i18n Security checking, what user can access an what they can't Consistent way of calling the service layer And somehow bring consistency to the debugging lines. Do better job with error handling and serving it to the user. I'm already on mission to do security logging with AOP :) I'm just looking for patterns I could implement to help me to do all of the above. Or just some general advice in case no patterns apply, or advice on something I didn't mention but is common practice.

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  • How to dump STDIN to a file, using C++ STL?

    - by Jimm Chen
    HHello all, this is a straight forward question, but not a straight forward answer can be found by just Googling today. Hope someone can show me a concise answer before I dig into those thick C++ books and finally find the solution out. Thank you. I'm writing this program so to make a workaround in this issue: Why do I get 'Bad file descriptor' when trying sys.stdin.read() in subversion pre-revprop-change py script? Note: Content from STDIN may be arbitrary binary data. Please use C++ STL functions, iostream, ifstream etc . If the file creation/writing failed, I'd like to catch the exception to know the case.

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  • Switch to selected tab by name in Jquery-UI Tabs

    - by Rob
    If I have three tabs: <div id="tabs"> <ul> <li><a href="#sample-tab-1"><span>One</span></a></li> <li><a href="#sample-tab-2"><span>Two</span></a></li> <li><a href="#sample-tab-3"><span>Three</span></a></li> </ul> </div> I would like to swap to #sample-tab-2 by it's name. I know I can switch to a tab if I know it's number, but in the case I've run into I won't know that. Notes: JQuery 1.3.1 / JQuery-UI 1.6rc6

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  • Why is passing a string literal into a char* arguament only sometimes a compiler error?

    - by Brian Postow
    I'm working in a C, and C++ program. We used to be compiling without the make-strings-writable option. But that was getting a bunch of warnings, so I turned it off. Then I got a whole bunch of errors of the form "Cannot convert const char* to char* in argmuent 3 of function foo". So, I went through and made a whole lot of changes to fix those. However, today, the program CRASHED because the literal "" was getting passed into a function that was expecting a char*, and was setting the 0th character to 0. It wasn't doing anything bad, just trying to edit a constant, and crashing. My question is, why wasn't that a compiler error? In case it matters, this was on a mac compiled with gcc-4.0.

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  • interfacing: simplified

    - by code wombat
    i've been doing some research on interfaces and a simple layman's explanation for what it truly is. For some reason people love using overly complex explanations and jargon to explain truly simple concepts (guess it makes them feel big) and i have a gut feeling it's the same in this case. so from what i could grasp, it seems like interfaces are nothing more than a way to reserve method names, their return type if any, and the type and amount of arguments they accept. so when a class implements an interface (or interfaces) it is forced to define the body of each method from the interface(s). Am i on the nose with this one or do i need to keep digging? p.s. i know javascript doesn't have support for interfaces, but i still need to understand the concept because there are quite a few places where it's shown how to emulate to an extent.

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  • PHP MySQLi and MySQLi_STMT: Which insert_id to use?

    - by Carvell Fenton
    Hello all, Both the MySQLi and MySQLi_STMT classes have an $insert_id property. If I am connected to my database using a MySQLi object (say $db), and then I perform an INSERT with a MySQLi_STMT object (say $stmt), to get the id of the last INSERT, should I use: $last_id = $db->insert_id; or $last_id = $stmt->insert_id; Or would they be the same, in which case it doesn't matter? I thought this might be a quick answer for someone, and save me the time of writing the test code to check it. Thanks in advance as always.

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  • Is there a faster TList implementation ?

    - by dmauric.mp
    My application makes heavy use of TList, so I was wondering if there are any alternative implementations that are faster or optimized for particular use case. I know of RtlVCLOptimize.pas 2.77, which has optimized implementations of several TList methods. But I'd like to know if there is anything else out there. I also don't require it to be a TList descendant, I just need the TList functionality regardless of how it's implemented. It's entirely possible, given the rather basic functionality TList provides, that there is not much room for improvement, but would still like to verify that, hence this question.

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  • navigation framework in silverlight 3 skipping constructor when usercontrol is of a derived type

    - by tarren
    Hi: I am using the NavigationFramework in Silverlight 3, and am running into issues where the constructor of the UserControl in the xaml I am loading is not being called, and I believe this is because the UserControl in the xaml I am calling is actually derived from another user control. I have stepped through the debugger with specific break points and the constructor is being ignored completey. I have MyWindowBlue which is of type uctrlBaseMyWindow. The constructor for uctrlBaseMyWindow is being called when the xaml is 'navigated to' but the constructor for MyWindowBlue is being ignored. This is not the case if I add the user control via markup directly. Anyone else have this issue? The code I am using to navigate to the MyWindowBlue is this.MyContentFrame.Navigate(new Uri("/Controls/uctrlMyWindowBlue.xaml", UriKind.Relative)); Has anyone run into this or could offer any help? Thanks

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  • How are variables bound to the body of a define_method?

    - by Chris
    While trying to brush up my Ruby skills I keep running across this case which I can't figure out an explanation for by just reading the API docs. An explanation would be greatly appreciated. Here's the example code: for name in [ :new, :create, :destroy ] define_method("test_#{name}") do puts name end end What I want/expect to happen is that the name variable will be bound to the block given to define_method and that when #test_new is called it will output "new". Instead each defined method outputs "destroy" -- the last value assigned to the name variable. What am I misunderstanding about define_method and its blocks? Thanks!

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  • What garbage collection algorithms do all 5 major browsers use?

    - by Martin Wittemann
    I am currently rethinking the object dispose handling of the qooxdoo JavaScript framework. Have a look at the following diagram (A is currently in scope): Let's say we want to delete B. Generally, we cut all reference between all objects. This means we cut connection 1 to 5 in the example. Is this really necessary? As far as I have read hear 1, browsers use the mark-and-sweep algorithm. In that case, we just need to cut reference 1 (connection to the scope) and 5 (connection to the DOM) which could be much faster. But can I be sure that all browsers use the mark-and-sweep algorithm or something similar? 1 http://stackoverflow.com/questions/864516/what-is-javascript-garbage-collection

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  • Does importing of packages change visibility of classes?

    - by Roman
    I jsut learned that A class may be declared with the modifier public, in which case that class is visible to all classes everywhere. If a class has no modifier (the default, also known as package-private), it is visible only within its own package. This is a clear statement. But this information interfere with my understanding of importing of packages (which easily can be wrong). I thought that importing a package I make classes from the imported package visible to the importing class. So, how does it work? Are public classes visible to all classes everywhere under condition that the package containing the public class is imported? Or there is not such a condition? What about the package-private classes? They are invisible no mater if the containing package was imported or not? ADDED: It seems to me that I got 2 answers which are marked as good (up-voted) and which contradict eachother.

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  • Using IF in T-SQL weakens or breaks execution plan caching?

    - by AnthonyWJones
    It has been suggest to me that the use of IF statements in t-SQL batches is detrimental to performance. I'm trying to find some confirmation of this assertion. I'm using SQL Server 2005 and 2008. The assertion is that with the following batch:- IF @parameter = 0 BEGIN SELECT ... something END ELSE BEGIN SELECT ... something else END SQL Server cannot re-use the execution plan generated because the next execution may need a different branch. This implies that SQL Server will eliminate one branch entirely from execution plan on the basis that for the current execution it can already determine which branch is needed. Is this really true? In addition what happens in this case:- IF EXISTS (SELECT ....) BEGIN SELECT ... something END ELSE BEGIN SELECT ... something else END where it's not possible to determine in advance which branch will be executed?

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  • Registering a delegate function with an ISO C++ callback (on mono)

    - by Stick it to THE MAN
    I am thinking of wrapping ISO C++ code in C# class. The only problem so far is how to deal with the C++ callbacks. In .Net languages (C# and Vb.Net), I believe the callback equivalent. Sticking with C# for now, can anyone recommend a way that I can register the C# delegate functions with my ISO C++ code. The ISO C++ code is a notification library, and I want to be able to "push" the notifications to the mono framework (i.e. C# delegates in this case). My underlying assumption is that the mechanism/steps to implement this would be the same for the .Net languages - I'll just have to code the actual delegates in the .Net language of choice - is that assumption correct? Last but not the least, is the question of thread saftey. The underlying ISO C++ code that I am exposing to .Net (mono to be more specific), is both re-ntrant and thread safe - do I have to do anything "extra" to call .Net delegate from my ISO C++ code?

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  • JSF session issue

    - by user234194
    I have got a situation where I have list of records say 10,000, I am using datatable and I am using paging,(10 records per display). I wanted to put put that list in the session as: facesContext........put("mylist", mylist); And in the getters of the mylist, I have public List<MyClass> getMyList() { if(mylist== null){ mylist= (List<MyClass>) FacesContext......getSessionMap().get("mylist"); } return mylist; } Now the problem is whene ever i click on paging button to go to second page, only the first records are displayed, I know i am missing some thing, and I have few questions: Is the way of putting the list in session correct. Is this the way I should be calling the list in my case. Thnaks in advance...

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  • How to deal with Rounding-off TimeSpan?

    - by infant programmer
    I take the difference between two DateTime fields, and store it in a TimeSpan variable, Now I have to round-off the TimeSpan by the following rules: if the minutes in TimeSpan is less than 30 then Minutes and Seconds must be set to zero, if the minutes in TimeSpan is equal to or greater than 30 then hours must be incremented by 1 and Minutes and Seconds must be set to zero. TimeSpan can also be a negative value, so in that case I need to preserve the sign.. I could be able to achieve the requirement if the TimeSpan wasn't a negative value, though I have written a code I am not happy with its inefficiency as it is more bulky .. Please suggest me a simpler and efficient method. Thanks regards,

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  • Efficiency of the .NET garbage collector

    - by Jonas B
    OK here's the deal. There are some people who put their lives in the hands of .NET's garbage collector and some who simply wont trust it. I am one of those who partially trusts it, as long as it's not extremely performance critical (I know I know.. performance critical + .net not the favored combination), in which case I prefer to manually dispose of my objects and resources. What I am asking is if there are any facts as to how efficient or inefficient performance-wise the garbage collector really is? Please don't share any personal opinions or likely-assumptions-based-on-experience, I want unbiased facts. I also don't want any pro/con discussions because it won't answer the question. Thanks

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  • resetting the image in an NSView

    - by Josan
    I think this is a very simple question, but I’m new to programming so I may be going about it in a wrong-headed way. I have a basic understanding of Objective-C writing terminal applications and am teaching myself how to use the Cocoa GUI. I understand how to use IBOutlet and IBAction to connect a simple button to a method that will repeatedly send random numbers to a textfield . I understand how to add a NSView file, connect it to a custom view in interface builder and draw a path through random points in the view when the application launches. (I’ve been putting this code inside the - (void)drawRect:(NSRect)dirtyRect method that is declared when the file is created). What I can’t seem to figure out is how to connect a button to an action that will then ‘refresh’ the view – in this case repopulate it with another set of random points connected with a path. Looking at the documentation, I think I should somehow be using – (void) setNeedsDisplay(BOOL)flag but nothing I have tried so far had worked. Please tell me, what am I missing here?

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