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  • ELMAH - Using custom error pages to collecting user feedback

    - by vdh_ant
    Hey guys I'm looking at using ELMAH for the first time but have a requirement that needs to be met that I'm not sure how to go about achieving... Basically, I am going to configure ELMAH to work under asp.net MVC and get it to log errors to the database when they occur. On top of this I be using customErrors to direct the user to a friendly message page when an error occurs. Fairly standard stuff... The requirement is that on this custom error page I have a form which enables to user to provide extra information if they wish. Now the problem arises due to the fact that at this point the error is already logged and I need to associate the loged error with the users feedback. Normally, if I was using my own custom implementation, after I log the error I would pass through the ID of the error to the custom error page so that an association can be made. But because of the way that ELMAH works, I don't think the same is quite possible. Hence I was wondering how people thought that one might go about doing this.... Cheers UPDATE: My solution to the problem is as follows: public class UserCurrentConextUsingWebContext : IUserCurrentConext { private const string _StoredExceptionName = "System.StoredException."; private const string _StoredExceptionIdName = "System.StoredExceptionId."; public virtual string UniqueAddress { get { return HttpContext.Current.Request.UserHostAddress; } } public Exception StoredException { get { return HttpContext.Current.Application[_StoredExceptionName + this.UniqueAddress] as Exception; } set { HttpContext.Current.Application[_StoredExceptionName + this.UniqueAddress] = value; } } public string StoredExceptionId { get { return HttpContext.Current.Application[_StoredExceptionIdName + this.UniqueAddress] as string; } set { HttpContext.Current.Application[_StoredExceptionIdName + this.UniqueAddress] = value; } } } Then when the error occurs, I have something like this in my Global.asax: public void ErrorLog_Logged(object sender, ErrorLoggedEventArgs args) { var item = new UserCurrentConextUsingWebContext(); item.StoredException = args.Entry.Error.Exception; item.StoredExceptionId = args.Entry.Id; } Then where ever you are later you can pull out the details by var item = new UserCurrentConextUsingWebContext(); var error = item.StoredException; var errorId = item.StoredExceptionId; item.StoredException = null; item.StoredExceptionId = null; Note this isn't 100% perfect as its possible for the same IP to have multiple requests to have errors at the same time. But the likely hood of that happening is remote. And this solution is independent of the session, which in our case is important, also some errors can cause sessions to be terminated, etc. Hence why this approach has worked nicely for us.

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  • How can I limit the cache used by copying so there is still memory available for other cache?

    - by Peter
    Basic situation: I am copying some NTFS disks in openSuSE. Each one is 2TB. When I do this, the system runs slow. My guesses: I believe it is likely due to caching. Linux decides to discard useful cache (eg. kde4 bloat, virtual machine disks, LibreOffice binaries, Thunderbird binaries, etc.) and instead fill all available memory (24 GB total) with stuff from the copying disks, which will be read only once, then written and never used again. So then any time I use these apps (or kde4), the disk needs to be read again, and reading the bloat off the disk again makes things freeze/hiccup. Due to the cache being gone and the fact that these bloated applications need lots of cache, this makes the system horribly slow. Since it is USB,the disk and disk controller are not the bottleneck, so using ionice does not make it faster. I believe it is the cache rather than just the motherboard going too slow, because if I stop everything copying, it still runs choppy for a while until it recaches everything. And if I restart the copying, it takes a minute before it is choppy again. But also, I can limit it to around 40 MB/s, and it runs faster again (not because it has the right things cached, but because the motherboard busses have lots of extra bandwidth for the system disks). I can fully accept a performance loss from my motherboard's IO capability being completely consumed (which is 100% used, meaning 0% wasted power which makes me happy), but I can't accept that this caching mechanism performs so terribly in this specific use case. # free total used free shared buffers cached Mem: 24731556 24531876 199680 0 8834056 12998916 -/+ buffers/cache: 2698904 22032652 Swap: 4194300 24764 4169536 I also tried the same thing on Ubuntu, which causes a total system hang instead. ;) And to clarify, I am not asking how to leave memory free for the "system", but for "cache". I know that cache memory is automatically given back to the system when needed, but my problem is that it is not reserved for caching of specific things. Question: Is there some way to tell these copy operations to limit memory usage so some important things remain cached, and therefore any slowdowns are a result of normal disk usage and not rereading the same commonly used files? For example, is there a setting of max memory per process/user/file system allowed to be used as cache/buffers?

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  • How to stream XML data using XOM?

    - by Jonik
    Say I want to output a huge set of search results, as XML, into a PrintWriter or an OutputStream, using XOM. The resulting XML would look like this: <?xml version="1.0" encoding="UTF-8"?> <resultset> <result> [child elements and data] </result> ... ... [1000s of result elements more] </resultset> Because the resulting XML document could be big (tens or hundreds of megabytes, perhaps), I want to output it in a streaming fashion (instead of creating the whole Document in memory and then writing that). The granularity of outputting one <result> at a time is fine, so I want to generate one <result> after another, and write it into the stream. Assume there's already a method that helps with iterating the results and generating Element objects: public nu.xom.Element getNextResult(); So I'd simply like to do something like this pseudocode (automatic flushing enabled, so don't worry about that) : open stream/writer write declaration write start tag for <resultset> while more results: write next <result> element write end tag for <resultset> close stream/writer I've been looking at Serializer, but the necessary methods, writeStartTag(Element), writeEndTag(Element), write(DocType) are protected, not public! Is there no other way than to subclass Serializer to be able to use those methods, or to manually write the start and end tags directly into the stream as Strings, bypassing XOM altogether? (The latter wouldn't be too bad in this simple example, but in the general case it would get quite ugly.) Am I missing something or is XOM just not made for this? With dom4j I could do this easily using XMLWriter - it has constructors that take a Writer or OutputStream, and methods writeOpen(Element), writeClose(Element), writeDocType(DocumentType) etc. Compare to XOM's Serializer where the only public write method is the one that takes a whole Document. Please refrain from answering if you're not familiar with XOM! I specifically want to know if and how you can do this kind of streaming with that library. (This is related to my question about the best dom4j replacement where XOM is a strong contender.)

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  • gcc/g++: error when compiling large file

    - by Alexander
    Hi, I have a auto-generated C++ source file, around 40 MB in size. It largely consists of push_back commands for some vectors and string constants that shall be pushed. When I try to compile this file, g++ exits and says that it couldn't reserve enough virtual memory (around 3 GB). Googling this problem, I found that using the command line switches --param ggc-min-expand=0 --param ggc-min-heapsize=4096 may solve the problem. They, however, only seem to work when optimization is turned on. 1) Is this really the solution that I am looking for? 2) Or is there a faster, better (compiling takes ages with these options acitvated) way to do this? Best wishes, Alexander Update: Thanks for all the good ideas. I tried most of them. Using an array instead of several push_back() operations reduced memory usage, but as the file that I was trying to compile was so big, it still crashed, only later. In a way, this behaviour is really interesting, as there is not much to optimize in such a setting -- what does the GCC do behind the scenes that costs so much memory? (I compiled with deactivating all optimizations as well and got the same results) The solution that I switched to now is reading in the original data from a binary object file that I created from the original file using objcopy. This is what I originally did not want to do, because creating the data structures in a higher-level language (in this case Perl) was more convenient than having to do this in C++. However, getting this running under Win32 was more complicated than expected. objcopy seems to generate files in the ELF format, and it seems that some of the problems I had disappeared when I manually set the output format to pe-i386. The symbols in the object file are by standard named after the file name, e.g. converting the file inbuilt_training_data.bin would result in these two symbols: binary_inbuilt_training_data_bin_start and binary_inbuilt_training_data_bin_end. I found some tutorials on the web which claim that these symbols should be declared as extern char _binary_inbuilt_training_data_bin_start;, but this does not seem to be right -- only extern char binary_inbuilt_training_data_bin_start; worked for me.

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  • Why is two-way binding in silverlight not working?

    - by Edward Tanguay
    According to how Silverlight TwoWay binding works, when I change the data in the FirstName field, it should change the value in CheckFirstName field. Why is this not the case? ANSWER: Thank you Jeff, that was it, for others: here is the full solution with downloadable code. XAML: <StackPanel> <Grid x:Name="GridCustomerDetails"> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="300"/> </Grid.ColumnDefinitions> <TextBlock VerticalAlignment="Center" Margin="10" Grid.Row="0" Grid.Column="0">First Name:</TextBlock> <TextBox Margin="10" Grid.Row="0" Grid.Column="1" Text="{Binding FirstName, Mode=TwoWay}"/> <TextBlock VerticalAlignment="Center" Margin="10" Grid.Row="1" Grid.Column="0">Last Name:</TextBlock> <TextBox Margin="10" Grid.Row="1" Grid.Column="1" Text="{Binding LastName}"/> <TextBlock VerticalAlignment="Center" Margin="10" Grid.Row="2" Grid.Column="0">Address:</TextBlock> <TextBox Margin="10" Grid.Row="2" Grid.Column="1" Text="{Binding Address}"/> </Grid> <Border Background="Tan" Margin="10"> <TextBlock x:Name="CheckFirstName"/> </Border> </StackPanel> Code behind: public Page() { InitializeComponent(); Customer customer = new Customer(); customer.FirstName = "Jim"; customer.LastName = "Taylor"; customer.Address = "72384 South Northern Blvd."; GridCustomerDetails.DataContext = customer; Customer customerOutput = (Customer)GridCustomerDetails.DataContext; CheckFirstName.Text = customer.FirstName; }

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  • Powershell $LastExitCode=0 but $?=False . Redirecting stderr to stdout gives NativeCommandError

    - by Colonel Panic
    Can anyone explain Powershell's surprising behaviour in the second example below? First, a example of sane behaviour: PS C:\> & cmd /c "echo Hello from standard error 1>&2"; echo "`$LastExitCode=$LastExitCode and `$?=$?" Hello from standard error $LastExitCode=0 and $?=True No surprises. I print a message to standard error (using cmd's echo). I inspect the variables $? and $LastExitCode. They equal to True and 0 respectively, as expected. However, if I ask Powershell to redirect standard error to standard output over the first command, I get a NativeCommandError: PS C:\> & cmd /c "echo Hello from standard error 1>&2" 2>&1; echo "`$LastExitCode=$LastExitCode and `$?=$?" cmd.exe : Hello from standard error At line:1 char:4 + cmd <<<< /c "echo Hello from standard error 1>&2" 2>&1; echo "`$LastExitCode=$LastExitCode and `$?=$?" + CategoryInfo : NotSpecified: (Hello from standard error :String) [], RemoteException + FullyQualifiedErrorId : NativeCommandError $LastExitCode=0 and $?=False My first question, why the NativeCommandError ? Secondly, why is $? False when cmd ran successfully and $LastExitCode is 0? Powershell's docs about_Automatic_Variables don't explicitly define $?. I always supposed it is True if and only if $LastExitCode is 0 but my example contradicts that. Here's how I came across this behaviour in the real-world (simplified). It really is FUBAR. I was calling one Powershell script from another. The inner script: cmd /c "echo Hello from standard error 1>&2" if (! $?) { echo "Job failed. Sending email.." exit 1 } # do something else Running this simply .\job.ps1, it works fine, no email is sent. However, I was calling it from another Powershell script, logging to a file .\job.ps1 2>&1 > log.txt. In this case, an email is sent! Here, the act of observing a phenomenon changes its outcome. This feels like quantum physics rather than scripting! [Interestingly: .\job.ps1 2>&1 may or not blow up depending on where you run it]

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  • Make an array of two.

    - by marharépa
    Hello! I'd like to make an array which tells my site's pages where to show in PHP. In $sor["site_id"] i've got two or four chars-lenght strings. example: 23, 42, 13, 1 In my other array (called to $pages_show) i want to give all the site_ids to an other id. $parancs="SELECT * FROM pages ORDER BY id"; $eredmeny=mysql_query($parancs) or die("Hibás SQL:".$parancs); while($sor=mysql_fetch_array($eredmeny)) { $pages[]=array( "id"=>$sor["id"], "name"=>$sor["name"], "title"=>$sor["title"], "description"=>$sor["description"], "keywords"=>$sor["keywords"] ); // this makes my pages array with the information about that page. $shower = explode(", ",$sor["site_id"]); // this is explode my site_id $pages_show[]=array( "id"=>$sor["id"], "where"=>$shower //to 'where' i want to put all the explode's elements one-by-one, to get the result like down ); This script gives me the following result: Array (3) 0 => Array (2) id => "29" where => Array (2) 0 => "17" 1 => "16" 1 => Array (2) id => "30" where => Array (1) 0 => "17" 2 => Array (2) id => "31" where => Array (1) 0 => "17" But in this case I'd like to be this: Array (4) 0 => Array (2) id => "29" where => "17" 1 => Array (2) id => "29" where => "16" 2 => Array (2) id => "30" where => "17" 3 => Array (2) id => "31" where => "17" Thanks for your help.

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  • How best to store Subversion version information in EAR's?

    - by Rene
    When receiving a bug report or an it-doesnt-work message one of my initials questions is always what version? With a different builds being at many stages of testing, planning and deploying this is often a non-trivial question. I the case of releasing Java JAR (ear, jar, rar, war) files I would like to be able to look in/at the JAR and switch to the same branch, version or tag that was the source of the released JAR. How can I best adjust the ant build process so that the version information in the svn checkout remains in the created build? I was thinking along the lines of: adding a VERSION file, but with what content? storing information in the META-INF file, but under what property with which content? copying sources into the result archive added svn:properties to all sources with keywords in places the compiler leaves them be I ended up using the svnversion approach (the accepted anwser), because it scans the entire subtree as opposed to svn info which just looks at the current file / directory. For this I defined the SVN task in the ant file to make it more portable. <taskdef name="svn" classname="org.tigris.subversion.svnant.SvnTask"> <classpath> <pathelement location="${dir.lib}/ant/svnant.jar"/> <pathelement location="${dir.lib}/ant/svnClientAdapter.jar"/> <pathelement location="${dir.lib}/ant/svnkit.jar"/> <pathelement location="${dir.lib}/ant/svnjavahl.jar"/> </classpath> </taskdef> Not all builds result in webservices. The ear file before deployment must remain the same name because of updating in the application server. Making the file executable is still an option, but until then I just include a version information file. <target name="version"> <svn><wcVersion path="${dir.source}"/></svn> <echo file="${dir.build}/VERSION">${revision.range}</echo> </target> Refs: svnrevision: http://svnbook.red-bean.com/en/1.1/re57.html svn info http://svnbook.red-bean.com/en/1.1/re13.html subclipse svn task: http://subclipse.tigris.org/svnant/svn.html svn client: http://svnkit.com/

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  • Forcing a checkbox bound to a DataSource to update when it has not been viewed yet.

    - by Scott Chamberlain
    Here is a test framework to show what I am doing: create a new project add a tabbed control on tab 1 put a button on tab 2 put a check box paste this code for its code (use default names for controls) public partial class Form1 : Form { private List<bool> boolList = new List<bool>(); BindingSource bs = new BindingSource(); public Form1() { InitializeComponent(); boolList.Add(false); bs.DataSource = boolList; checkBox1.DataBindings.Add("Checked", bs, ""); this.button1.Click += new System.EventHandler(this.button1_Click); this.checkBox1.CheckedChanged += new System.EventHandler(this.checkBox1_CheckedChanged); } bool updating = false; private void button1_Click(object sender, EventArgs e) { updating = true; boolList[0] = true; bs.ResetBindings(false); Application.DoEvents(); updating = false; } private void checkBox1_CheckedChanged(object sender, EventArgs e) { if (!updating) MessageBox.Show("CheckChanged fired outside of updating"); } } The issue is if you run the program and look at tab 2 then press the button on tab 1 the program works as expected, however if you press the button on tab 1 then look at tab 2 the event for the checkbox will not fire untill you look at tab 2. The reason for this is the controll on tab 2 is not in the "created" state, so its binding to change the checkbox from unchecked to checked does not happen until after the control has been "Created". checkbox1.CreateControl() does not do anything because according to MSDN CreateControl does not create a control handle if the control's Visible property is false. You can either call the CreateHandle method or access the Handle property to create the control's handle regardless of the control's visibility, but in this case, no window handles are created for the control's children. I tried getting the value of Handle(there is no public CreateHandle() for CheckBox) but still the same result. Any suggestions other than have the program quickly flash all of my tabs that have data-bound check boxes when it first loads? EDIT-- per Jaxidian's suggestion I created a new class public class newcheckbox : CheckBox { public new void CreateHandle() { base.CreateHandle(); } } I call CreateHandle() right after updating = true same results as before.

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  • Hibernate mapping to object that already exists

    - by teehoo
    I have two classes, ServiceType and ServiceRequest. Every ServiceRequest must specify what kind of ServiceType it is. All ServiceType's are predefined in the database, and ServiceRequest is created at runtime by the client. Here are my .hbm files: <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceRequest" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="quantity"> <column name="quantity" not-null="true"/> </property> <many-to-one cascade="all" class="xxx.model.entity.ServiceType" column="service_type" name="serviceType" not-null="false" unique="false"/> </class> </hibernate-mapping> and <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceType" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="description"> <column name="description" not-null="false"/> </property> <property name="cost"> <column name="cost" not-null="true"/> </property> <property name="enabled"> <column name="enabled" not-null="true"/> </property> </class> </hibernate-mapping> When I run this, I get com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails I think my problem is that when I create a new ServiceRequest object, ServiceType is one of its properties, and therefore when I'm saving ServiceRequest to the database, Hibernate attempts to insert the ServiceType object once again, and finds that it is already exists. If this is the case, how do I make it so that Hibernate points to the exists ServiceType instead of trying to insert it again?

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  • Exception opening TAdoDataset: Arguments are of the wrong type, are out of acceptable range, or are

    - by Dave Falkner
    I've been trying to debug the following problem for several weeks now - this method is called from several places within the same datamodule, but this exception (from the subject line of this post) only occurs when integers for a certain purpose (pickup orders vs. orders that we ship through a carrier) are used - and don't ask me how the application can tell the difference between one integer's purpose and another! Furthermore, I cannot duplicate this issue on my machine - the error occurs on a warehouse machine but not my own development machine, even when working with the same production database. I have suspected an MDAC version conflict between the two machines, but have run a version checker and confirmed that both machines are running 2.8, and additionally have confirmed this by logging the TAdoDataset's .Version property at runtime. function TdmESShip.SecondaryID(const PrimaryID : Integer ): String; begin try with qESPackage2 do begin if Active then Close; LogMessage('-----------------------------------'); LogMessage('Version: ' + FConnection.Version); LogMessage('DB Info: ' + FConnection.Properties['Initial Catalog'].Value + ' ' + FConnection.Properties['Data Source'].Value); LogMessage('Setting the parameter.'); Parameters.ParamByName('ParameterName').Value := PrimaryID; LogMessage('Done setting the parameter.'); Open; Ninety-nine times out of 100 this logging code logs a successful operation as follows: Version: 2.8 DB Info: (database name and instance) Setting the parameter. Done setting the parameter. Opened the dataset. But then whenever a "pickup" order is processed, this exception gets thrown whenever the dataset is opened: Version: 2.8 DB Info: (database name and instance) Setting the parameter. Done setting the parameter. GetESPackageID() threw an exception. Type: EOleException, Message: Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another Error: Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another for packageID 10813711 I've tried eliminating the parameter and have built the commandtext for this dataset programmatically, suspecting that some part of the TParameter's configuration might be out of whack, but the same error occurs under the same circumstances. I've tried every combination of TParameter properties that I can think of - this is the millionth TParameter I've created for my millionth dataset, and I've never encountered this error. I've even created a second dataset from scratch and removed all references to the original dataset in case some property of the original dataset in the .dfm might be corrupted, but the same error occurs under the same circumstances. The commandtext for this dataset is a simple select ValueA from TableName where ValueB = @ParameterB I'm about ready to do something extreme, such as writing a web service to look these values up - it feels right now as though I could destroy my machine, rebuild it, rewrite this entire application from scratch, and the application would still know to throw an exception whenever I try to look up a secondary value from a primary value, but only for pickup orders, and only from the one machine in the warehouse, but I'm probably missing something simple. So, any help anyone could provide would be greatly appreciated.

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  • How to show percentage of 'memory used' in a win32 process?

    - by pj4533
    I know that memory usage is a very complex issue on Windows. I am trying to write a UI control for a large application that shows a 'percentage of memory used' number, in order to give the user an indication that it may be time to clear up some memory, or more likely restart the application. One implementation used ullAvailVirtual from MEMORYSTATUSEX as a base, then used HeapWalk() to walk the process heap looking for additional free memory. The HeapWalk() step was needed because we noticed that after a while of running the memory allocated and freed by the heap was never returned and reported by the ullAvailVirtual number. After hours of intensive working, the ullAvailVirtual number no longer would accurately report the amount of memory available. However, this method proved not ideal, due to occasional odd errors that HeapWalk() would return, even when the process heap was not corrupted. Further, since this is a UI control, the heap walking code was executing every 5-10 seconds. I tried contacting Microsoft about why HeapWalk() was failing, escalated a case via MSDN, but never got an answer other than "you probably shouldn't do that". So, as a second implementation, I used PagefileUsage from PROCESS_MEMORY_COUNTERS as a base. Then I used VirtualQueryEx to walk the virtual address space adding up all regions that weren't MEM_FREE and returned a value for GetMappedFileNameA(). My thinking was that the PageFileUsage was essentially 'private bytes' so if I added to that value the total size of the DLLs my process was using, it would be a good approximation of the amount of memory my process was using. This second method seems to (sorta) work, at least it doesn't cause crashes like the heap walker method. However, when both methods are enabled, the values are not the same. So one of the methods is wrong. So, StackOverflow world...how would you implement this? which method is more promising, or do you have a third, better method? should I go back to the original method, and further debug the odd errors? should I stay away from walking the heap every 5-10 seconds? Keep in mind the whole point is to indicate to the user that it is getting 'dangerous', and they should either free up memory or restart the application. Perhaps a 'percentage used' isn't the best solution to this problem? What is? Another idea I had was a color based system (red, yellow, green, which I could base on more factors than just a single number)

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  • iPhone OS: KVO: Why is my Observer only getting notified at applicationDidfinishLaunching

    - by nickthedude
    I am basically trying to implement an achievement tracking setup in my app. I have a managedObjectModel class called StatTracker to keep track of all sorts of stats and I want my Achievement tracking class to be notified when those stats change so I can check them against a value and see if the user has earned an achievement. I've tried to impliment KVO and I think I'm pretty close to making it happen but the problem I'm running into is this: So in the appDelegate i have an Ivar for my Achievement tracker class, I attach it as an observer to a property value of my statTracker core data entity in the applicationDidFinishLaunching method. I know its making the connection because I've been able to trigger a UIAlert in my AchievementTracker instance, and I've put several log statements that should be triggered whenever the value on the StatTracker's property changes. the log statement appears only once at the application launch. I'm wondering if I'm missing something in the whole object lifecycle scheme of things, I just don't understand why the observer stops getting notified of changes after the applicationDidFinishLaunching method has run. Does it have something to do with the scope of the AchievementTracker reference or more likely the reference to my core data StatTracker is going away once that method finishes up. I guess I'm not sure the right place to place these if that is the case. Would love some help. Here is the code where I add the observer in my appDidFinishLaunching method: [[CoreDataSingleton sharedCoreDataSingleton] incrementStatTrackerStat:@"timesLaunched"]; achievementsObserver = [[AchievementTracker alloc] init]; StatTracker *object = nil; object = [[[CoreDataSingleton sharedCoreDataSingleton] getStatTracker] objectAtIndex:0]; NSLog(@"%@",[object description]); [[CoreDataSingleton sharedCoreDataSingleton] addObserver:achievementsObserver toStat:@"refreshCount"]; here is the code in my core data singleton: -(void) addObserver:(id)observer toStat:(NSString *) statToObserve { NSLog(@"observer added"); NSArray *array = [[NSArray alloc] init]; array = [self getStatTracker]; [[array objectAtIndex:0] addObserver:observer forKeyPath:statToObserve options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld context:NULL]; } and my AchievementTracker: - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { NSLog(@"achievemnt hit"); //NSLog("%@", [change description]); if ([keyPath isEqual:@"refreshCount"] && ((NSInteger)[change valueForKey:@"NSKeyValueObservingOptionOld"] == 60) ) { NSLog(@"achievemnt hit inside"); UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"title" message:@"achievement unlocked" delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:nil]; [alert show]; } }

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  • How hard programming is? Really. [closed]

    - by Bubba88
    Hi! The question is about your perception of programming activity. How hard/exacting this task is? There is much buzz about programming nowadays, people say that programmers are smart, very technical and abstract at a time, know much about world, psychology etc.. They say, that programmers got really powerful brain thing, cause there is much to keep in consideration simultaneously again with much information folded into each other associatively (up 10 levels of folding they say))) Still, there are some terms to specify at our own.. So that is the question: What do you think about programming in general? Is it hard? Is it 'for everyone' or for the particular kind of people only? How much non-CS background do you need to program (just to program, really; enterprise applications for example)? How long is the learning curve? (again, for programming in general) And another bunch of random questions: - If you were not to like/love programming, would that be a serious trouble bothering your current employment? - If you were to start from the beginning, would you chose that direction this time? - What other areas (jobs or maybe hobbies) are comparable to programming in the way they can explode someone's lovely brain? - Is 'non turing-complete programming' (SQL, XML, etc.) comparable to what we do or is it really way easier, less requiring, cheap and akin to cooking :)? Well, the essence is: How would you describe programming activity WRT to its difficulty? Or, on the other hand: Did you ever catch yourself thinking at some point: OMG, it's sooo hard! I don't know how would I ever program, even carried away this way and doing programming just for fun? It's very interesting to know your opinion, your'e the programmers after all. I mean much people must be exaggerating/speculating about the thing they do not really know about. But that musn't be the case here on SO :) P.S.: I'll try my best to update this post later, and you please edit it too. At least I'll get decent English in my question text :)

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  • itextsharp PdfCopy and landscape pages

    - by Andreas Rehm
    I'm using itextsharp to join mutiple pdf documents and add a footer. My code works fine - except for landscape pages - it isn't detecting the page rotation - the footer is not centerd for landscape: public static int AddPagesFromStream(Document document, PdfCopy pdfCopy, Stream m, bool addFooter, int detailPages, string footer, int footerPageNumOffset, int numPages, string pageLangString, string printLangString) { CreateFont(); try { m.Seek(0, SeekOrigin.Begin); var reader = new PdfReader(m); // get page count var pdfPages = reader.NumberOfPages; var i = 0; // add pages while (i < pdfPages) { i++; // import page with pdfcopy var page = pdfCopy.GetImportedPage(reader, i); // get page center float posX; float posY; var rotation = page.BoundingBox.Rotation; if (rotation == 0 || rotation == 180) { posX = page.Width / 2; posY = 0; } else { posX = page.Height / 2; posY = 20f; } var ps = pdfCopy.CreatePageStamp(page); var cb = ps.GetOverContent(); // add footer cb.SetColorFill(BaseColor.WHITE); var gs1 = new PdfGState {FillOpacity = 0.8f}; cb.SetGState(gs1); cb.Rectangle(0, 0, document.PageSize.Width, 46f + posY); cb.Fill(); // Text cb.SetColorFill(BaseColor.BLACK); cb.SetFontAndSize(baseFont, 7); cb.BeginText(); // create text var pages = string.Format(pageLangString, i + footerPageNumOffset, numPages); cb.ShowTextAligned(PdfContentByte.ALIGN_CENTER, printLangString, posX, 40f + posY, 0f); cb.ShowTextAligned(PdfContentByte.ALIGN_CENTER, footer, posX, 28f + posY, 0f); cb.ShowTextAligned(PdfContentByte.ALIGN_CENTER, pages, posX, 20f + posY, 0f); cb.EndText(); ps.AlterContents(); // add page to new pdf pdfCopy.AddPage(page); } // close PdfReader reader.Close(); // return number of pages return i; } catch (Exception e) { Console.WriteLine(e); return 0; } } How do I detect the page rotation (e.g. landscape) format in this case? The given example works for PdfReader but not for PdfCopy. Edit: Why do I need PdfCopy? I tried copying a word pdf export. Some word hyperlinks will not work when you try to copy pages with PdfReader. Only PdfCopy transfers all needed page informations. Edit: (SOLVED) You need to use reader.GetPageRotation(i);

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  • PostgreSQL - fetch the row which has the Max value for a column

    - by Joshua Berry
    I'm dealing with a Postgres table (called "lives") that contains records with columns for time_stamp, usr_id, transaction_id, and lives_remaining. I need a query that will give me the most recent lives_remaining total for each usr_id There are multiple users (distinct usr_id's) time_stamp is not a unique identifier: sometimes user events (one by row in the table) will occur with the same time_stamp. trans_id is unique only for very small time ranges: over time it repeats remaining_lives (for a given user) can both increase and decrease over time example: time_stamp|lives_remaining|usr_id|trans_id ----------------------------------------- 07:00 | 1 | 1 | 1 09:00 | 4 | 2 | 2 10:00 | 2 | 3 | 3 10:00 | 1 | 2 | 4 11:00 | 4 | 1 | 5 11:00 | 3 | 1 | 6 13:00 | 3 | 3 | 1 As I will need to access other columns of the row with the latest data for each given usr_id, I need a query that gives a result like this: time_stamp|lives_remaining|usr_id|trans_id ----------------------------------------- 11:00 | 3 | 1 | 6 10:00 | 1 | 2 | 4 13:00 | 3 | 3 | 1 As mentioned, each usr_id can gain or lose lives, and sometimes these timestamped events occur so close together that they have the same timestamp! Therefore this query won't work: SELECT b.time_stamp,b.lives_remaining,b.usr_id,b.trans_id FROM (SELECT usr_id, max(time_stamp) AS max_timestamp FROM lives GROUP BY usr_id ORDER BY usr_id) a JOIN lives b ON a.max_timestamp = b.time_stamp Instead, I need to use both time_stamp (first) and trans_id (second) to identify the correct row. I also then need to pass that information from the subquery to the main query that will provide the data for the other columns of the appropriate rows. This is the hacked up query that I've gotten to work: SELECT b.time_stamp,b.lives_remaining,b.usr_id,b.trans_id FROM (SELECT usr_id, max(time_stamp || '*' || trans_id) AS max_timestamp_transid FROM lives GROUP BY usr_id ORDER BY usr_id) a JOIN lives b ON a.max_timestamp_transid = b.time_stamp || '*' || b.trans_id ORDER BY b.usr_id Okay, so this works, but I don't like it. It requires a query within a query, a self join, and it seems to me that it could be much simpler by grabbing the row that MAX found to have the largest timestamp and trans_id. The table "lives" has tens of millions of rows to parse, so I'd like this query to be as fast and efficient as possible. I'm new to RDBM and Postgres in particular, so I know that I need to make effective use of the proper indexes. I'm a bit lost on how to optimize. I found a similar discussion here. Can I perform some type of Postgres equivalent to an Oracle analytic function? Any advice on accessing related column information used by an aggregate function (like MAX), creating indexes, and creating better queries would be much appreciated! P.S. You can use the following to create my example case: create TABLE lives (time_stamp timestamp, lives_remaining integer, usr_id integer, trans_id integer); insert into lives values ('2000-01-01 07:00', 1, 1, 1); insert into lives values ('2000-01-01 09:00', 4, 2, 2); insert into lives values ('2000-01-01 10:00', 2, 3, 3); insert into lives values ('2000-01-01 10:00', 1, 2, 4); insert into lives values ('2000-01-01 11:00', 4, 1, 5); insert into lives values ('2000-01-01 11:00', 3, 1, 6); insert into lives values ('2000-01-01 13:00', 3, 3, 1);

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  • Persistent (purely functional) Red-Black trees on disk performance

    - by Waneck
    I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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  • Wondering about a way to conserve memory in C# using List<> with structs

    - by Michael Ryan
    I'm not even sure how I should phrase this question. I'm passing some CustomStruct objects as parameters to a class method, and storing them in a List. What I'm wondering is if it's possible and more efficient to add multiple references to a particular instance of a CustomStruct if a equivalent instance it found. This is a dummy/example struct: public struct CustomStruct { readonly int _x; readonly int _y; readonly int _w; readonly int _h; readonly Enum _e; } Using the below method, you can pass one, two, or three CustomStruct objects as parameters. In the final method (that takes three parameters), it may be the case that the 3rd and possibly the 2nd will have the same value as the first. List<CustomStruct> _list; public void AddBackground(CustomStruct normal) { AddBackground(normal, normal, normal); } public void AddBackground(CustomStruct normal, CustomStruct hover) { AddBackground(normal, hover, hover); } public void AddBackground(CustomStruct normal, CustomStruct hover, CustomStruct active) { _list = new List<CustomStruct>(3); _list.Add(normal); _list.Add(hover); _list.Add(active); } As the method stands now, I believe it will create new instances of CustomStruct objects, and then adds a reference of each to the List. It is my understanding that if I instead check for equality between normal and hover and (if equal) insert normal again in place of hover, when the method completes, hover will lose all references and eventually be garbage collected, whereas normal will have two references in the List. The same could be done for active. That would be better, right? The CustomStruct is a ValueType, and therefore one instance would remain on the Stack, and the three List references would just point to it. The overall List size is determined not by the object Type is contains, but by its Capacity. By eliminating the "duplicate" CustomStuct objects, you allow them to be cleaned up. When the CustomStruct objects are passed to these methods, new instances are created each time. When the structs are added to the List, is another copy made? For example, if i pass just one CustomStruct, AddBackground(normal) creates a copy of the original variable, and then passes it three times to Addbackground(normal, hover, active). In this method, three copies are made of the original copy. When the three local variables are added to the List using Add(), are additional copies created inside Add(), and does that defeat the purpose of any equality checks as previously mentioned? Am I missing anything here?

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  • Why does SFINAE not apply to this?

    - by Simon Buchan
    I'm writing some simple point code while trying out Visual Studio 10 (Beta 2), and I've hit this code where I would expect SFINAE to kick in, but it seems not to: template<typename T> struct point { T x, y; point(T x, T y) : x(x), y(y) {} }; template<typename T, typename U> struct op_div { typedef decltype(T() / U()) type; }; template<typename T, typename U> point<typename op_div<T, U>::type> operator/(point<T> const& l, point<U> const& r) { return point<typename op_div<T, U>::type>(l.x / r.x, l.y / r.y); } template<typename T, typename U> point<typename op_div<T, U>::type> operator/(point<T> const& l, U const& r) { return point<typename op_div<T, U>::type>(l.x / r, l.y / r); } int main() { point<int>(0, 1) / point<float>(2, 3); } This gives error C2512: 'point<T>::point' : no appropriate default constructor available Given that it is a beta, I did a quick sanity check with the online comeau compiler, and it agrees with an identical error, so it seems this behavior is correct, but I can't see why. In this case some workarounds are to simply inline the decltype(T() / U()), to give the point class a default constructor, or to use decltype on the full result expression, but I got this error while trying to simplify an error I was getting with a version of op_div that did not require a default constructor*, so I would rather fix my understanding of C++ rather than to just do what works. Thanks! *: the original: template<typename T, typename U> struct op_div { static T t(); static U u(); typedef decltype(t() / u()) type; }; Which gives error C2784: 'point<op_div<T,U>::type> operator /(const point<T> &,const U &)' : could not deduce template argument for 'const point<T> &' from 'int', and also for the point<T> / point<U> overload.

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  • How to troubleshoot a Highcharts script that's not rendering data when date is added and hanging the JS engine with large datasets?

    - by ylluminate
    I have a Highchart JS graph that I'm building in Rails (although I don't think Ruby has real bearing on this problem unless it's the Date output format) to which I'm adding the timestamp of each datapoint. Presently the array of floats is rendering fine without timestamps, however when I add the timestamp to the series it fails to rend. What's worse is that when the series has hundreds of entries all sorts of problems arise, not the least of which is the browser entirely hanging and requiring a force quit / kill. I'm using the following to build the array of arrays data series: series1 = readings.map{|row| [(row.date.to_i * 1000), (row.data1.to_f if BigDecimal(row.data1) != BigDecimal("-1000.0"))] } This yields a result like this: series: [{"name":"Data 1","data":[[1326262980000,1.79e-09],[1326262920000,1.29e-09],[1326262860000,1.22e-09],[1326262800000,1.42e-09],[1326262740000,1.29e-09],[1326262680000,1.34e-09],[1326262620000,1.31e-09],[1326262560000,1.51e-09],[1326262500000,1.24e-09],[1326262440000,1.7e-09],[1326262380000,1.24e-09],[1326262320000,1.29e-09],[1326262260000,1.53e-09],[1326262200000,1.23e-09],[1326262140000,1.21e-09]],"color":"blue"}] Yet nothing appears on the graph as noted. Notwithstanding, when I compare the data series in one of their very similar examples here: http://www.highcharts.com/demo/spline-irregular-time It appears that really the data series are formatted identically (except in mine I use the timestamp vs date method). This leads me to think I've got a problem with the timestamp output, but I'm just not able to figure out where / how as I'm converting the date output to an integer multipled by 1000 to convert it to milliseconds as per explained in a similar Railscasts tutorial. I would very much appreciate it if someone could point me in the right direction here as to what I may be doing wrong. What could cause no data to appear on the graph in smaller sized sets (<100 points) and when into the hundreds causes an apparent hang in the javascript engine in this case? Perhaps ultimately the key lies here as this is the entire js that's being generated and not rendering: jQuery(function() { // 1. Define JSON options var options = { chart: {"defaultSeriesType":"spline","renderTo":"chart_name"}, title: {"text":"Title"}, legend: {"layout":"vertical","style":{}}, xAxis: {"title":{"text":"UTC Time"},"type":"datetime"}, yAxis: [{"title":{"text":"Left Title","margin":10}},{"title":{"text":"Right Groups Title"},"opposite":true}], tooltip: {"enabled":true}, credits: {"enabled":false}, plotOptions: {"areaspline":{}}, series: [{"name":"Data 1","data":[[1326262980000,1.79e-08],[1326262920000,1.69e-08],[1326262860000,1.62e-08],[1326262800000,1.42e-08],[1326262740000,1.29e-08],[1326262680000,1.34e-08],[1326262620000,1.31e-08],[1326262560000,1.51e-08],[1326262500000,1.64e-08],[1326262440000,1.7e-08],[1326262380000,1.64e-08],[1326262320000,1.69e-08],[1326262260000,1.53e-08],[1326262200000,1.23e-08],[1326262140000,1.21e-08]],"color":"blue"},{"name":"Data 2","data":[[1326262980000,9.79e-09],[1326262920000,9.78e-09],[1326262860000,9.8e-09],[1326262800000,9.82e-09],[1326262740000,9.88e-09],[1326262680000,9.89e-09],[1326262620000,1.3e-06],[1326262560000,1.32e-06],[1326262500000,1.33e-06],[1326262440000,1.33e-06],[1326262380000,1.34e-06],[1326262320000,1.33e-06],[1326262260000,1.32e-06],[1326262200000,1.32e-06],[1326262140000,1.32e-06]],"color":"red"}], subtitle: {} }; // 2. Add callbacks (non-JSON compliant) // 3. Build the chart var chart = new Highcharts.StockChart(options); });

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  • Html.RadioButtonListFor problem

    - by ognjenb
    <%using (Html.BeginForm("Numbers", "Numbers", FormMethod.Post)) { %> <table id="numbers"> <tr> <th> prvi_br </th> <th> drugi_br </th> <th> treci_br </th> </tr> <%int rb =1; %>" <% foreach (var item in Model) { %> <tr> <td> <%= Html.Encode(item.prvi_br) %> <input type="radio" name="<%= Html.Encode(rb) %>" value="<%= Html.Encode(rb) %>" /> </td> <td> <%= Html.Encode(item.drugi_br) %> <input type="radio" name="<%= Html.Encode(rb) %>" value="<%= Html.Encode(rb) %>"/> </td> <td> <%= Html.Encode(item.treci_br) %> <input type="radio" name="<%= Html.Encode(rb) %>" value="<%= Html.Encode(rb) %>"/> </td> </tr> <% rb++; %> <% } %> </table> <p> <input type="submit" value="Save" /> </p> <%} %> How post this form with only one checked radio button? In my case all of 3 radio buttons is possible to check. How to restrict so that it is possible check only one radio. In this article I found good solutions but it can not be applied because I have a table.

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  • How to successfully implement og:image for the LinkedIn

    - by Sabo
    THE PROBLEM: I am trying, without much success, to implement open graph image on site: http://www.guarenty-group.com/cz/ The homepage is completeply bypassing the og:image tag, where internal pages are reading all images from the site and place og:image as the last option. Other social networks are working fine on both internal pages and homepage. THE CONFIGURATION: I have no share buttons or alike, all I want is to be able to share the link via my profile. The image is well over 300x300px: http://guarenty-group.com/img/gg_seal.png Here is how my head tag looks like: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Guarenty Group : Pojištení pro nájemce a pronajímatelé</title> <meta name="keywords" content="" /> <meta name="description" content="Guarenty Group pojištuje príjem z nájmu pronajímatelum, kauci nájemcum - aby nemuseli platit velkou cástku v hotovostí predem - a dále nájemcum pojištuje príjmy, aby meli na nájem pri nemoci, úrazu ci nezamestnání." /> <meta name="image_src" content="http://guarenty-group.com/img/gg_seal.png" /> <meta name="image_url" content="http://guarenty-group.com/img/gg_seal.png" /> <meta property="og:title" content="Pojištení pro nájemce a pronajímatelé" /> <meta property="og:url" content="http://guarenty-group.com/cz/" /> <meta property="og:image" content="http://guarenty-group.com/img/gg_seal.png" /> <meta property="og:description" content="Guarenty Group pojištuje príjem z nájmu pronajímatelum, kauci nájemcum - aby nemuseli platit velkou cástku v hotovostí predem - a dále nájemcum pojištuje príjmy, aby meli na nájem pri nemoci, úrazu ci nezamestnání [...]" /> ... </head> THE TESTING RESULTS: In order to trick the cache i have tested the site with http://www.guarenty-group.com/cz/?try=N, where I have changed the N every time. The strange thing is that images found for different value of N is different. Sometimes there is no image, sometimes there is 1, 2 or 3 images, but each time there is a different set of images. But, in any case I could not find the image specified in the og:graph! MY QUESTIONS: https://developer.linkedin.com/documents/setting-display-tags-shares is saying one thing, and the personnel on the support forum is saying "over 300" Does anyone know What is the official minimum dimension of the image (both w and h)? Can an image be too large? Should I use the xmlns, should I not use xmlns or it doesn't matter? What are the maximum (and minimum) lengths for og:title and og:description tags? Any other suggestion is of course welcomed :) Thanks in advance, cheers~

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  • Repeating fields in similar database tables

    - by user1738833
    I have been tasked with working on a database that I have never seen before and I'm looking at the DB structure. Some of the central and most heavily queried and joined tables look like virtual duplicates of each other. Here's a massively simplified representation of the situation, with business-sensitive information changed, listing hypothetical table names and fields: TopLevelGroup: PK_TLGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK SubGroup: PK_SubGroupId, FK_ParentTopLevelGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK SubSubGroup: PK_SubSUbGroupId, FK_ParentSubGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK I haven't listed the types of the fields as I don't think it's particularly important to the situation. In addition, it's worth saying that rather than four repeated fields as in the example above, I'm looking at 86 repeated fields. For the most part, those fields genuinely do represent "facts" about the primary table entity, so it's not automatically wrong for that reason. In addition, the "groups" represented here have a property inheritance relationship. If DisplaysXOnBill is NULL in the SubSubGroup, it takes the value of DisplaysXOnBillfrom it's parent, the SubGroup, and so-on up to the TopLevelGroup. Further, the requirements will never require that the model extends beyond three levels, so there is no need for flexibility in that area. Is there a design smell from several tables which describe very similar entities having almost identical fields? If so, what might be a better design of the example above? I'm using the phrase "design smell" to indicate a possible problem. Of course, in any given situation, a particular design might well be the best solution. I'm looking for a more general answer - wondering what might be wrong with this design and what might be the better design were that the case. Possibly related, but not primary questions: Is this database schema in a reasonably normal form (e.g. to 3NF), insofar as can be told from the information I've provided. I can't see a problem with the requirements of 2NF and 3NF, except in their inheriting the requirements of 1NF. Is 1NF satisfied though? Are repeating groups allowed in different tables? Is there a best-practice method for implementing the inheritance relationship in a database as I require? The method above feels clunky to me because any query on the SubSubGroup necessarily needs to join onto the SubGroup and the TopLevelGroup tables to collect inherited facts, which can make even trivial joins requiring facts from the SubSubGroup table rather long-winded. There are, of course, political considerations to making a relatively large change like this. For the purpose of this question, I'm happy to ignore that fact in the interests of keeping the answers ring-fenced to the technical problem.

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  • Parallel.For maintain input list order on output list

    - by romeozor
    I'd like some input on keeping the order of a list during heavy-duty operations that I decided to try to do in a parallel manner to see if it boosts performance. (It did!) I came up with a solution, but since this was my first attempt at anything parallel, I'd need someone to slap my hands if I did something very stupid. There's a query that returns a list of card owners, sorted by name, then by date of birth. This needs to be rendered in a table on a web page (ASP.Net WebForms). The original coder decided he would construct the table cell-by-cell (TableCell), add them to rows (TableRow), then each row to the table. So no GridView, allegedly its performance is bad, but the performance was very poor regardless :). The database query returns in no time, the most time is spent on looping through the results and adding table cells etc. I made the following method to maintain the original order of the list: private TableRow[] ComposeRows(List<CardHolder> queryResult) { int queryElementsCount = queryResult.Count(); // array with the query's size var rowArray = new TableRow[queryElementsCount]; Parallel.For(0, queryElementsCount, i => { var row = new TableRow(); var cell = new TableCell(); // various operations, including simple ones such as: cell.Text = queryResult[i].Name; row.Cells.Add(cell); // here I'm adding the current item to it's original index // to maintain order in the output list rowArray[i] = row; }); return rowArray; } So as you can see, because I'm returning a very different type of data (List<CardHolder> -> TableRow[]), I can't just simply omit the ordering from the original query to do it after the operations. Also, I also thought it would be a good idea to Dispose() the objects at the end of each loop, because the query can return a huge list and letting cell and row objects pile up in the heap could impact performance.(?) How badly did I do? Does anyone have a better solution in case mine is flawed?

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  • problem with custom NSProtocol and caching on iPhone

    - by TomSwift
    My iPhone app embeds a UIWebView which loads html via a custom NSProtocol handler I have registered. My problem is that resources referenced in the returned html, which are also loaded via my custom protocol handler, are cached and never reloaded. In particular, my stylesheet is cached: <link rel="stylesheet" type="text/css" href="./styles.css" /> The initial request to load the html in the UIWebView looks like this: NSString* strUrl = [NSMutableString stringWithFormat: @"myprotocol:///entry?id=%d", entryID ]; NSURL* url = [NSURL URLWithString: strUrl]; [_pCurrentWebView loadRequest: [NSURLRequest requestWithURL: url cachePolicy: NSURLRequestReloadIgnoringLocalCacheData timeoutInterval: 60 ]]; (note the cache policy is set to ignore, and I've verified this cache policy carries through to subsequent requests for page resources on the initial load) The protocol handler loads the html from a database and returns it to the client using code like this: // create the response record NSURLResponse *response = [[NSURLResponse alloc] initWithURL: [request URL] MIMEType: mimeType expectedContentLength: -1 textEncodingName: textEncodingName]; // get a reference to the client so we can hand off the data id client = [self client]; // turn off caching for this response data [client URLProtocol: self didReceiveResponse:response cacheStoragePolicy: NSURLCacheStorageNotAllowed]; // set the data in the response to our jfif data [client URLProtocol: self didLoadData:data]; [data release]; (Note the response cache policy is "not allowed"). Any ideas how I can make it NOT cache my styles.css resource? I need to be able to dynamically alter the content of this resource on subsequent loads of html that references this file. I thought clearing the shared url cache would work, but it doesnt: [[NSURLCache sharedURLCache] removeAllCachedResponses]; One thing that does work, but it's terribly inefficient, is to dynamically cache-bust the url for the stylesheet by adding a timestamp parameter: <link rel="stylesheet" type="text/css" href="./styles.css?ts=1234567890" /> To make this work I have to load my html from the db, search and replace the url for the stylesheet with a cache-busting parameter that changes on each request. I'd rather not do this. My presumption is that there is no problem if I were to load my content via the built-in HTTP protocol. In that case, I'm guessing that the UIWebView looks at any Cache-Control flags in the NSURLHTTPResponse object's http headers and abides by them. Since my NSURLResponseObject has no http headers (it's not http...) then perhaps UIWebView just decides to cached the resource (ignoring the NSURLRequest caching directive?). Ideas???

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