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  • Mono WCF NetTcp service takes only one client at a time

    - by vene
    While trying to build a client-server WCF application in Mono we ran into some issues. Reducing it to just a bare example we found that the service only accepts one client at a time. If another client attempts to connect, it hangs until the first one disconnects. Simply changing to BasicHttpBinding fixes it but we need NetTcpBinding for duplex communication. Also the problem does not appear if compiled under MS .NET. EDIT: I doubt (and hope not) that Mono doesn't support what I'm trying to do. Mono code usually throws NotImplementedExceptions in such cases as far as I noticed. I am using Mono v2.6.4 This is how the service is opened in our basic scenario: public static void Main (string[] args) { var binding = new NetTcpBinding (); binding.Security.Mode = SecurityMode.None; var address = new Uri ("net.tcp://localhost:8080"); var host = new ServiceHost (typeof(Hello)); host.AddServiceEndpoint (typeof(IHello), binding, address); ServiceThrottlingBehavior behavior = new ServiceThrottlingBehavior () { MaxConcurrentCalls = 100, MaxConcurrentSessions = 100, MaxConcurrentInstances = 100 }; host.Description.Behaviors.Add (behavior); host.Open (); Console.ReadLine (); host.Close (); } The client channel is obtained like this: var binding = new NetTcpBinding (); binding.Security.Mode = SecurityMode.None; var address = new EndpointAddress ("net.tcp://localhost:8080/"); var client = new ChannelFactory<IHello> (binding, address).CreateChannel (); As far as I know this is a Simplex connection, isn't it? The contract is simply: [ServiceContract] public interface IHello { [OperationContract] string Greet (string name); } Service implementation has no ServiceModel tags or attributes. I'll update with details as required.

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  • how to intercept processing when Session.IsNewSession is true

    - by Cen
    I have a small 4-page application for my customers to work through. They fill out information. If they let it sit too long, and the Session timeout out, I want to pop up a javascript alert that their session has expired, and that they need to start over. At that point, then redirected to the beginning page of the application. I'm getting some strange behavior. I'm stepping through code, forcing my Sessioni.IsNewSession to be true. At this point, I write out a call to Javascript to a Literal Control placed at the bottom of the . The javascript is called, and the redirection occurs. However, what is happening is.. I am pressing a button which is more or less a "Next Page" button and triggering this code. The next page is being displayed, and then the Alert and redirection occurs. The result I was expecting was to stay on the same page I received the "Timeout", with the alert to pop-up over it, then redirection. I'm checking for Session.IsNewSession in a BaseClass for these pages, overriding the OnInit event. Any ideas why I am getting this behavior? Thanks!

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  • "hour" int taken from NSDate not behaving as expected at midnight??

    - by Eric
    I feel like I've lost my mind. Can someone tell me what's going on here? Also, I'm sure there is a better way to do what I'm trying to do, but I'm not interested in that now. I'd just like to solve the mystery of why my ints are not responding to logic as expected. // Set "At: " field close to current time NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"HH"]; int hour = [[dateFormatter stringFromDate:[NSDate date]] intValue]; [dateFormatter setDateFormat:@"mm"]; int minute = [[dateFormatter stringFromDate:[NSDate date]] intValue]; NSLog(@"currently %i:%i",hour, minute); if(hour >= 12){ // convert to AM/PM selectedMeridiem = 1; if(hour != 12){ hour = hour - 12; } } else{ selectedMeridiem = 0; } selectedHour = hour - 1; if(selectedHour <= 0){ selectedHour = 11; } When I debug the above code with my clock set to 12:XX AM, the integer "hour" returned is 0. But then any if statements with the condition if(hour == 0) are not evaluated. Likewise, this would not be evaluated either: if(hour < 1). The code above puts the hour int into another int, selectedHour (don't worry about why I'm doing this for now), but selectedHour suffers from the same weird behavior; the if(selectedHour <= 0) line is never evaluated. Am I going crazy, or am I just an idiot? Maybe there's some behavior of 0 integers that I'm not aware of. All of my code runs fine as long as it's not 12:XX AM.

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  • Why do my CouchDB databases grow so fast?

    - by konrad
    I was wondering why my CouchDB database was growing to fast so I wrote a little test script. This script changes an attributed of a CouchDB document 1200 times and takes the size of the database after each change. After performing these 1200 writing steps the database is doing a compaction step and the db size is measured again. In the end the script plots the databases size against the revision numbers. The benchmarking is run twice: The first time the default number of document revision (=1000) is used (_revs_limit). The second time the number of document revisions is set to 1. The first run produces the following plot The second run produces this plot For me this is quite an unexpected behavior. In the first run I would have expected a linear growth as every change produces a new revision. When the 1000 revisions are reached the size value should be constant as the older revisions are discarded. After the compaction the size should fall significantly. In the second run the first revision should result in certain database size that is then keeps during the following writing steps as every new revision leads to the deletion of the previous one. I could understand if there is a little bit of overhead needed to manage the changes but this growth behavior seems weird to me. Can anybody explain this phenomenon or correct my assumptions that lead to the wrong expectations?

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  • Exception on inserting into Access 2010 in C Sharp

    - by slao.it
    Hello, I am getting this exception when inserting into a Access 2010 database. Ex: System.Data.OleDb.OleDbException (0x80040E14): Syntax error in string in query expression ''CityName ?'. at System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(OleDbHResult hr) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteNonQuery() at ReadingData.Program.Main(String[] args) in C:\Users\user\documents\visual studio 2010\Projects\ReadingData\ReadingData\Program.cs:line 238 INSERT INTO CranbrookMain (ID,BlockNo,Plot,SubPlot,Code,Type,LastName,FirstName,ServiceHome,ServiceAddress,ServiceCity,Notes) VALUES ('1','Y','37','DS','C2','O','SMITH','John','Service Inc.','520B SLATER ROAD N.W.','CityName','CityName ? ') insertSQL = "INSERT INTO CranbrookMain (ID,BlockNo,Plot,SubPlot,Code,Type,LastName," + "FirstName,ServiceHome,ServiceAddress,ServiceCity,Notes) VALUES (" + "'"+id+ "','" + blockNo + "','" + plot + "','" + subPlot + "','" + code + "','" + type + "','" + lastname + "','" + firstname + "','" + serviceHome + "','" + serviceAddress + "','" + serviceCity + "','" + notes +"')"; Console.WriteLine(); OleDbCommand cmd = new OleDbCommand(insertSQL, con); // creating query command cmd.ExecuteNonQuery(); The error occurs in cmd.ExecuteNonQuery() function call. The above SQL INSERT statement works fine if I directly execute in the Access 2010 file.

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  • Does Perl auto-vivify variables used as references in subroutine calls?

    - by FM
    I've declared 2010 to be the year of higher-order programming, so I'm learning Haskell. The introduction has a slick quick-sort demo, and I thought, "Hey, that's easy to do in Perl". It turned to be easier than I expected. Note that I don't have to worry about whether my partitions ($less and $more) are defined. Normally you can't use an undefined value as an array reference. use strict; use warnings; use List::MoreUtils qw(part); my @data = (5,6,7,4,2,9,10,9,5,1); my @sorted = qsort(@data); print "@sorted\n"; sub qsort { return unless @_; my $pivot = shift @_; my ($less, $more) = part { $_ < $pivot ? 0 : 1 } @_; # Works, even though $less and $more are sometimes undefined. return qsort(@$less), $pivot, qsort(@$more); } As best I can tell, Perl will auto-vivify a variable that you try to use as a reference -- but only if you are passing it to a subroutine. For example, my call to foo() works, but not the attempted print. use Data::Dumper qw(Dumper); sub foo { print "Running foo(@_)\n" } my ($x); print Dumper($x); # Fatal: Can't use an undefined value as an ARRAY reference. # print @$x, "\n"; # But this works. foo(@$x); # Auto-vivification: $x is now []. print Dumper($x); My questions: Am I understanding this behavior correctly? What is the explanation or reasoning behind why Perl does this? Is this behavior explained anywhere in the docs?

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  • MS Query Analizer/Management Studio replacement?

    - by kprobst
    I've been using SQL Server since version 6.5 and I've always been a bit amazed at the fact that the tools seem to be targeted to DBAs rather than developers. I liked the simplicity and speed of the Query Analizer for example, but hated the built-in editor, which was really no better than a syntax coloring-capable Notepad. Now that we have Management Studio the management part seems a bit better but from a developer standpoint the tools is even worse. Visual Studio's excellent text editor... without a way to customize keyboard bindings!? Don't get me started on how unusable is the tree-based management hierarchy. Why can't I re-root the tree on a list of stored procs for example the way the Enterprise Manager used to allow? Now I have a treeview that needs to be scrolled horizontally, which makes it eminently useless. The SQL server support in Visual Studio is fantastic for working with stored procedures and functions, but it's terrible as a general ad hoc data query tool. I've tried various tools over the years but invariably they seem to focus on the management side and shortchange the developer in me. I just want something with basic admin capabilities, good keyboard support and requisite DDL functionality (ideally something like the Query Analyzer). At this point I'm seriously thinking of using vim+sqlcmd and a console... I'm that desperate :) Those of you who work day in and day out with SQL Server and Visual Studio... do you find the tools to be adequate? Have you ever wished they were better and if you have found something better, could you share please? Thanks!

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  • Why my events aren't registered after postback?

    - by lucian.jp
    I have a problem where I have a page with a checkbox : <asp:CheckBox runat="server" ID="chkSelectAll" OnCheckedChanged="chkSelectAll_CheckedChanged" EnableViewState="true" Text='<%# CommonFunctions.GetText(Page, "CreateTask", "chkSelectAll.text") %>' AutoPostBack="true" /> First I had the problem that when the event was raised the checkbox wasn't keeping the checked property value. This is still strange because nowhere in the application we set the EnableViewState to false and by default it should be true. Well this behavior was fixed by puting EnableViewState="true". So now, I have a checkbox that when I first load the page, wworks correctly. I check the box, the event is raised Checked property valu is good and the method is executed. Postback completes and renders the page. I check the box back to false, the event is not triggered and the page is reloaded with the previous data but the Checked Property stays at true. So after the first postback I seem to loose behavior of event and ViewState. We suspect the fact that we move dynamically the controls in the page (See answer here) But this suspicion doesn't explain why everything works perfectly after the first load and stops working after first PostBack. EDIT CODE SAMPLE I created a test project where you can experience my problem. At load if you check any checkbox both raise their respective event. After postback only the second raise both events. I seem to have a problem when I register the events after moving control.

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  • Can't wrap my head around appengine data store persistence

    - by aloo
    Hi, I've run into the "can't operate on multiple entity groups in a single transaction." problem when using APPENGINE FOR JAVA w/ JDO with the following code: PersistenceManager pm = PMF.get().getPersistenceManager(); Query q = pm.newQuery("SELECT this FROM " + TypeA.class.getName() + " WHERE userId == userIdParam "); q.declareParameters("String userIdParam"); List<TypeA> poos = (List<TypeA>) q.execute(userIdParam); for (TypeA a : allTypeAs) { a.setSomeField(someValue); } pm.close(); } The problem it seems is that I can't operate on a multiple entities at the same time b/c they arent in the same entity group while in a transaction. Even though it doesn't seem like I'm in a transaction, appengine generates one because I have the following set in my jdoconfig.xml: <property name="datanucleus.appengine.autoCreateDatastoreTxns" value="true"/> Fine. So far I think I understand. BUT - if I replace TypeA in the above code, with TypeB - I don't get the error. I don't believe there is anything different between type a and type b - they both have the same key structure. They do have different fields but that shouldn't matter, right? My question is - what could possible be different between TypeA and TypeB that they give this different behavior? And consequently what do you I fundamentally misunderstand that this behavior could even exist.... Thanks.

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  • find the children in jquery

    - by armin etemadi
    i have a tree structure,there is an unordered list(ul) in that tree.i have li items in it,and in that li items it could be a span or an ul list. this is one part of my codes : <li id="main_li"> <div class="first_division"></div> <span>products</span> <ul style="display: block;"> <li> <div class="division1"></div> <span>products_cat_1</span> <ul style="display: none;"> <li> <span>products_cat_1_milk</span> </li> </ul> </li> <li> <span>products_yoghurt</span> </li> <li> <span>products_butter</span> </li> </ul> </li> i want to access li elements in ul tag where the parent li id is "main_li",i want to get it done by clicking on the span within li. how can i do this with jquery?

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  • When to choose which machine learning classifier?

    - by LM
    Suppose I'm working on some classification problem. (Fraud detection and comment spam are two problems I'm working on right now, but I'm curious about any classification task in general.) How do I know which classifier I should use? (Decision tree, SVM, Bayesian, logistic regression, etc.) In which cases is one of them the "natural" first choice, and what are the principles for choosing that one? Examples of the type of answers I'm looking for (from Manning et al.'s "Introduction to Information Retrieval book": http://nlp.stanford.edu/IR-book/html/htmledition/choosing-what-kind-of-classifier-to-use-1.html): a. If your data is labeled, but you only have a limited amount, you should use a classifier with high bias (for example, Naive Bayes). [I'm guessing this is because a higher-bias classifier will have lower variance, which is good because of the small amount of data.] b. If you have a ton of data, then the classifier doesn't really matter so much, so you should probably just choose a classifier with good scalability. What are other guidelines? Even answers like "if you'll have to explain your model to some upper management person, then maybe you should use a decision tree, since the decision rules are fairly transparent" are good. I care less about implementation/library issues, though. Also, for a somewhat separate question, besides standard Bayesian classifiers, are there 'standard state-of-the-art' methods for comment spam detection (as opposed to email spam)? [Not sure if stackoverflow is the best place to ask this question, since it's more machine learning than actual programming -- if not, any suggestions for where else?]

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  • VS 2008 C++ build output?

    - by STingRaySC
    Why when I watch the build output from a VC++ project in VS do I see: 1Compiling... 1a.cpp 1b.cpp 1c.cpp 1d.cpp 1e.cpp [etc...] 1Generating code... 1x.cpp 1y.cpp [etc...] The output looks as though several compilation units are being handled before any code is generated. Is this really going on? I'm trying to improve build times, and by using pre-compiled headers, I've gotten great speedups for each ".cpp" file, but there is a relatively long pause during the "Generating Code..." message. I do not have "Whole Program Optimization" nor "Link Time Code Generation" turned on. If this is the case, then why? Why doesn't VC++ compile each ".cpp" individually (which would include the code generation phase)? If this isn't just an illusion of the output, is there cross-compilation-unit optimization potentially going on here? There don't appear to be any compiler options to control that behavior (I know about WPO and LTCG, as mentioned above). EDIT: The build log just shows the ".obj" files in the output directory, one per line. There is no indication of "Compiling..." vs. "Generating code..." steps. EDIT: I have confirmed that this behavior has nothing to do with the "maximum number of parallel project builds" setting in Tools - Options - Projects and Solutions - Build and Run. Nor is it related to the MSBuild project build output verbosity setting. Indeed if I cancel the build before the "Generating code..." step, the ".obj" files will not exist for the most recent set of "compiled" files. E.g., if I cancel the build during "c.cpp" above, I will see only "a.obj" and "b.obj".

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  • Strange Matlab error: "??? Subscript indices must either be real positive integers or logicals"

    - by Roee Adler
    I have a function func that returns a vector a. I usually plot a and then perform further analysis on it. I have a certain scenario when once I try to plot a, I get a "??? Subscript indices must either be real positive integers or logicals" error. Take a look at the following piece of code to see the vector's behavior: K>> a a = 5.7047 6.3529 6.4826 5.5750 4.1488 5.8343 5.3157 5.4454 K>> plot(a) ??? Subscript indices must either be real positive integers or logicals. K>> for i=1:length(a); b(i) = a(i); end; K>> b b = 5.7047 6.3529 6.4826 5.5750 4.1488 5.8343 5.3157 5.4454 K>> plot(b) ??? Subscript indices must either be real positive integers or logicals. The scenario where this happens is when I call function func from within another function (call it outer_func), and return the result directly as outer_func's result. When debugging inside outer_func, I can plot a properly, but outside the scope of outer_func, its result has the above behavior. What can cause this? Where do I start from?

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  • Dynamic Hierarchical Javascript Object Loop

    - by user1684586
    var treeData = {"name" : "A", "children" : [ {"name" : "B", "children": [ {"name" : "C", "children" :[]} ]} ]}; THE ARRAY BEFORE SHOULD BE EMPTY. THE ARRAY AFTER SHOULD BE POPULATED DEPENDING ON THE NUMBER OF NODES NEEDED THAT WILL BE DEFINED FROM A DYNAMIC VALUE THAT IS PASSED. I would like to build the hierarchy dynamically with each node created as a layer/level in the hierarchy having its own array of nodes. THIS SHOULD FORM A TREE STRUCTURE. This is hierarchy structure is described in the above code. This code has tree level simple for demonstrating the layout of the hierarchy of values. There should be a root node, and an undefined number of nodes and levels to make up the hierarchy size. Nothing should be fixed besides the root node. I do not need to read the hierarchy, I need to construct it. The array should start {"name" : "A", "children" : []} and every new node as levels would be created {"name" : "A", "children" : [HERE-{"name" : "A", "children" : []}]}. In the child array, going deeper and deeper. Basically the array should have no values before the call, except maybe the root node. After the function call, the array should comprise of the required nodes of a number that may vary with every call. Every child array will contain one or more node values. There should be a minimum of 2 node levels, including the root. It should initially be a Blank canvas, that is no predefined array values.

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  • Getting the name of a child class in the parent class (static context)

    - by Benoit Myard
    Hi everybody, I'm building an ORM library with reuse and simplicity in mind; everything goes fine except that I got stuck by a stupid inheritance limitation. Please consider the code below: class BaseModel { /* * Return an instance of a Model from the database. */ static public function get (/* varargs */) { // 1. Notice we want an instance of User $class = get_class(parent); // value: bool(false) $class = get_class(self); // value: bool(false) $class = get_class(); // value: string(9) "BaseModel" $class = __CLASS__; // value: string(9) "BaseModel" // 2. Query the database with id $row = get_row_from_db_as_array(func_get_args()); // 3. Return the filled instance $obj = new $class(); $obj->data = $row; return $obj; } } class User extends BaseModel { protected $table = 'users'; protected $fields = array('id', 'name'); protected $primary_keys = array('id'); } class Section extends BaseModel { // [...] } $my_user = User::get(3); $my_user->name = 'Jean'; $other_user = User::get(24); $other_user->name = 'Paul'; $my_user->save(); $other_user->save(); $my_section = Section::get('apropos'); $my_section->delete(); Obviously, this is not the behavior I was expecting (although the actual behavior also makes sense).. So my question is if you guys know of a mean to get, in the parent class, the name of child class.

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  • Trouble Running Leaks Instrument

    - by TheGeoff
    I'm having trouble running the Leaks Instrument since installing the 3.0 SDK. An NDA disclaimer here I don't think this is a 3.0 SDK issue, just a configuration problem. So I'm looking for advice on configuring the tools in question not the 3.0 SDK per se. Here’s the breakdown of the behavior I am seeing. My Application is compiled to OS version 2.2. I can run it out of XCode in debug mode on the Simulator and Device running 2.2, 2.2.1, 3.0. If I start it with Performance Tools - Leaks, I get an error message from the OS, “The application xxxx quit unexpectedly”, “Ignore, Report, Relaunch.” If I click “Ignore” one of two things will happen, either Leaks tells me it couldn’t attach, or Leaks stop responding to input and I have to Force Quit. Interesting thing is the Simulator starts in 3.0 OS. If I start Instruments Manually and attach to a running 2.2 Simulator it shows the same behavior. If I attach Leaks to an iPhone Device it works. It seems that once I launch Leaks my app won't run in the simulator until I do a new build. Any ideas for getting my Simulator/Leaks/Xcode synced back up? Thanks, Geoff

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  • Duplicate elements when adding XElement to XDocument

    - by Andy
    I'm writing a program in C# that will go through a bunch of config.xml files and update certain elements, or add them if they don't exist. I have the portion down that updates an element if it exists with this code: XDocument xdoc = XDocument.Parse(ReadFile(_file)); XElement element = xdoc.Elements("project").Elements("logRotator") .Elements("daysToKeep").Single(); element.Value = _DoRevert; But I'm running into issues when I want to add an element that doesn't exist. Most of the time part of the tree is in place and when I use my code it adds another identical tree, and that causes the program reading the xml to blow up. here is how I am attempting to do it xdoc.Element("project").Add(new XElement("logRotator", new XElement("daysToKeep", _day))); and that results in a structure like this(The numToKeep tag was already there): <project> <logRotator> <daysToKeep>10</daysToKeep> </logRotator> <logRotator> <numToKeep>13</numToKeep> </logRotator> </project> but this is what I want <project> <logRotator> <daysToKeep>10</daysToKeep> <numToKeep>13</numToKeep> </logRotator> </project>

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  • C++0x rvalue references and temporaries

    - by Doug
    (I asked a variation of this question on comp.std.c++ but didn't get an answer.) Why does the call to f(arg) in this code call the const ref overload of f? void f(const std::string &); //less efficient void f(std::string &&); //more efficient void g(const char * arg) { f(arg); } My intuition says that the f(string &&) overload should be chosen, because arg needs to be converted to a temporary no matter what, and the temporary matches the rvalue reference better than the lvalue reference. This is not what happens in GCC and MSVC. In at least G++ and MSVC, any lvalue does not bind to an rvalue reference argument, even if there is an intermediate temporary created. Indeed, if the const ref overload isn't present, the compilers diagnose an error. However, writing f(arg + 0) or f(std::string(arg)) does choose the rvalue reference overload as you would expect. From my reading of the C++0x standard, it seems like the implicit conversion of a const char * to a string should be considered when considering if f(string &&) is viable, just as when passing a const lvalue ref arguments. Section 13.3 (overload resolution) doesn't differentiate between rvalue refs and const references in too many places. Also, it seems that the rule that prevents lvalues from binding to rvalue references (13.3.3.1.4/3) shouldn't apply if there's an intermediate temporary - after all, it's perfectly safe to move from the temporary. Is this: Me misreading/misunderstand the standard, where the implemented behavior is the intended behavior, and there's some good reason why my example should behave the way it does? A mistake that the compiler vendors have somehow all made? Or a mistake based on common implementation strategies? Or a mistake in e.g. GCC (where this lvalue/rvalue reference binding rule was first implemented), that was copied by other vendors? A defect in the standard, or an unintended consequence, or something that should be clarified?

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  • Hierarchical/Nested Database Structure for Comments

    - by Stephen Melrose
    Hi, I'm trying to figure out the best approach for a database schema for comments. The problem I'm having is that the comments system will need to allow nested/hierarchical comments, and I'm not sure how to design this out properly. My requirements are, Comments can be made on comments, so I need to store the tree hierarchy I need to be able to query the comments in the tree hierarchy order, but efficiently, preferably in a fast single query, but I don't know if this is possible I'd need to make some wierd queries, e.g. pull out the latest 5 root comments, and a maximum of 3 children for each one of those I read an article on the MySQL website on this very subject, http://dev.mysql.com/tech-resources/articles/hierarchical-data.html The "Nested Set Model" in theory sounds like it will do what I need, except I'm worried about querying the thing, and also inserting. If this is the right approach, How would I do my 3rd requirement above? If I have 2000 comments, and I add a new sub-comment on the first comment, that will be a LOT of updating to do. This doesn't seem right to me? Or is there a better approach for the type of data I'm wanting to store and query? Thank you

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  • C++ destructos causing crash's

    - by larsonator
    ok, so i got a some what intricate program that simulates the uni systems of students, units, and students enrolling in units. Students are stored in a binary search tree, Units are stored in a standard list. Student has a list of Unit Pointers, to store which units he/she is enrolled in Unit has a list of Student pointers, to store students which are enrolled in that unit. The unit collections (storing units in a list) as made as a static variable where the main function is, as is the Binary search tree of students. when its finaly time to close the program, i call the destructors of each. but at some stage, during the destructors on the unit side, Unhandled exception at 0x002e4200 in ClassAllocation.exe: 0xC0000005: Access violation reading location 0x00000000. UnitCollection destructor: UnitCol::~UnitCol() { list<Unit>::iterator itr; for(itr = UnitCollection.begin(); itr != UnitCollection.end();) { UnitCollection.pop_front(); itr = UnitCollection.begin(); } } Unit Destructor Unit::~Unit() { } now i got the same sorta problem on the student side of things BST destructors void StudentCol::Destructor(const BTreeNode * r) { if(r!= 0) { Destructor(r->getLChild()); Destructor(r->getRChild()); delete r; } } StudentCol::~StudentCol() { Destructor(root); } Student Destructor Student::~Student() { } so yeah any help would be greatly appreciated

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  • How can I control the height of a ListView in WPF, using a complex DataTemplate with DataTriggers?

    - by Rob Perkins
    I have a ListView element with a DataTemplate for each ListViewItem defined as follows. When run, the ListView's height is not collapsed onto the items in the view, which is undesirable behavior: <DataTemplate x:Key="LicenseItemTemplate"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions> <TextBlock Grid.Row="0" Text="{Binding company}"></TextBlock> <Grid Grid.Row="1" Style="{StaticResource HiddenWhenNotSelectedStyle}"> <Grid.RowDefinitions> <RowDefinition /> </Grid.RowDefinitions> <Button Grid.Row="0">ClickIt</Button> </Grid> </Grid> </DataTemplate> The second row of the outer grid has a style applied which looks like this. The purpose of the style is to : <Style TargetType="{x:Type Grid}" x:Key="HiddenWhenNotSelectedStyle" > <Style.Triggers> <DataTrigger Binding="{Binding Path=IsSelected, RelativeSource={ RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem} } }" Value="False"> <Setter Property="Grid.Visibility" Value="Collapsed" /> </DataTrigger> <DataTrigger Binding="{Binding Path=IsSelected, RelativeSource={ RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem} } }" Value="True"> <Setter Property="Grid.Visibility" Value="Visible" /> </DataTrigger> </Style.Triggers> </Style> The ListView renders like this: The desired appearance is this, when none of the elements are selected: ...with, of course, the ListView's height adjusting to accommodate the additional content when the second grid is made visible by selection. What can I do to get the desired behavior?

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  • Python raw strings and trailing back slashes.

    - by dash-tom-bang
    I ran across something once upon a time and wondered if it was a Python "bug" or at least a misfeature. I'm curious if anyone knows of any justifications for this behavior. I thought of it just now reading "Code Like a Pythonista," which has been enjoyable so far. I'm only familiar with the 2.x line of Python. Raw strings are strings that are prefixed with an r. This is great because I can use backslashes in regular expressions and I don't need to double everything everywhere. It's also handy for writing throwaway scripts on Windows, so I can use backslashes there also. (I know I can also use forward slashes, but throwaway scripts often contain content cut&pasted from elsewhere in Windows.) So great! Unless, of course, you really want your string to end with a backslash. There's no way to do that in a 'raw' string. In [9]: r'\n' Out[9]: '\\n' In [10]: r'abc\n' Out[10]: 'abc\\n' In [11]: r'abc\' ------------------------------------------------ File "<ipython console>", line 1 r'abc\' ^ SyntaxError: EOL while scanning string literal In [12]: r'abc\\' Out[12]: 'abc\\\\' So one slash before the closing quote is an error, but two slashes gives you two slashes! Certainly I'm not the only one that is bothered by this? Thoughts on why 'raw' strings are 'raw, except for slash-quote'? I mean, if I wanted to embed a single quote in there I'd just use double quotes around the string, and vice versa. If I wanted both, I'd just triple quote. If I really wanted three quotes in a row in a raw string, well, I guess I'd have to deal, but is this considered "proper behavior"?

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  • What happens when we combine RAII and GOTO ?

    - by Robert Gould
    I'm wondering, for no other purpose than pure curiosity (because no one SHOULD EVER write code like this!) about how the behavior of RAII meshes with the use of Goto (lovely idea isn't it). class Two { public: ~Two() { printf("2,"); } }; class Ghost { public: ~Ghost() { printf(" BOO! "); } }; void foo() { { Two t; printf("1,"); goto JUMP; } Ghost g; JUMP: printf("3"); } int main() { foo(); } When running the following code in VS2005 I get the following output: 1,2,3 BOO! However I imagined, guessed, hoped that 'BOO!' wouldn't actually appear as the Ghost should have never been instantiated (IMHO, because I don't know the actual expected behavior of this code). Any Guru out there knows what's up? Just realized that if I instantiate an explicit constructor for Ghost the code doesn't compile... class Ghost { public: Ghost() { printf(" HAHAHA! "); } ~Ghost() { printf(" BOO! "); } }; Ah, the mystery ...

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  • NSPredicate cause update editing to return NSFetchedResultsChangeDelete not NSFetchedResultsChangeUp

    - by Matthew Weiss
    I have predicate inside of - (NSFetchedResultsController *)fetchedResultsController in a standard way starting from the CoreDataBook example. NSPredicate *predicate = [NSPredicate predicateWithFormat:@"state=%@ && date = %@ && date < %@", @"1",fromDate,toDate]; [fetchRequest setPredicate:predicate]; This works fine however when editing an item, it returns with NSFetchedResultsChangeDelete not Update. When the main view returns, it is missing the item. If I restart the simulator the delete was not saved and the correct editing result is shown the the predicate working correctly. case NSFetchedResultsChangeDelete: [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; break; I can confirm the behavior by commenting out the two predicate lines ONLY and then all works as it should correctly returning with the full set after editing and calling NSFetchedResultsChangeUpdate instead of NSFetchedResultsChangeDelete. I have read http://matteocaldari.it/2009/11/multiple-contexts-controllers-delegates-and-coredata-bug who reports similar behavior but I have not found a work around to my problem. I can

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  • Correct Delphi compiler switches to stop in the user's code, not my component's

    - by Jeremy Mullin
    I'm modifying our VCL components so the end user's application links to our dcu files, instead of building our source code each time. We have everything working, but I want the debugger to stop on the user's code when an exception is raised. At first it would stop in our dcu and open the CPU window. I was able to prevent that by removing debug info from the dcu files. But now it still doesn't stop in the users code (like DevExpress libraries and others do). The following screencast is a short example. The first time I cause an exception in the DevExpress code, and the debugger correctly stops in my button event. The second time I cause an exception in my components, but the debugger doesn't have my button event on the call stack, and doesn't show me where the problem was. Any ideas why? http://screencast.com/t/NjhlOTRk Currently building the DCU's with these options: -$W+ -$D- -h -w -q Update: The TDataSet methods in between my component and the button event seem to cause this behavior. If I instead call a direct method of my table, I get the expected behavior. I'm guessing there isn't anything I can do about this, but I'm still curious why it happens.

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