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  • Java: Tracking a user login session - Session EJBs vs HTTPSession

    - by bguiz
    If I want to keep track of a conversational state with each client using my web application, which is the better alternative - a Session Bean or a HTTP Session - to use? Using HTTP Session: //request is a variable of the class javax.servlet.http.HttpServletRequest //UserState is a POJO HttpSession session = request.getSession(true); UserState state = (UserState)(session.getAttribute("UserState")); if (state == null) { //create default value .. } String uid = state.getUID(); //now do things with the user id Using Session EJB: In the implementation of ServletContextListener registered as a Web Application Listener in WEB-INF/web.xml: //UserState NOT a POJO this this time, it is //the interface of the UserStateBean Stateful Session EJB @EJB private UserState userStateBean; public void contextInitialized(ServletContextEvent sce) { ServletContext servletContext = sce.getServletContext(); servletContext.setAttribute("UserState", userStateBean); ... In a JSP: public void jspInit() { UserState state = (UserState)(getServletContext().getAttribute("UserState")); ... } Elsewhere in the body of the same JSP: String uid = state.getUID(); //now do things with the user id It seems to me that the they are almost the same, with the main difference being that the UserState instance is being transported in the HttpRequest.HttpSession in the former, and in a ServletContext in the case of the latter. Which of the two methods is more robust, and why?

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  • OOP design issue: Polymorphism

    - by Graham Phillips
    I'm trying to solve a design issue using inheritance based polymorphism and dynamic binding. I have an abstract superclass and two subclasses. The superclass contains common behaviour. SubClassA and SubClassB define some different methods: SubClassA defines a method performTransform(), but SubClassB does not. So the following example 1 var v:SuperClass; 2 var b:SubClassB = new SubClassB(); 3 v = b; 4 v.performTransform(); would cause a compile error on line 4 as performTransform() is not defined in the superclass. We can get it to compile by casting... (v as SubClassA).performTransform(); however, this will cause a runtime exception to be thrown as v is actually an instance of SubClassB, which also does not define performTransform() So we can get around that by testing the type of an object before casting it: if( typeof v == SubClassA) { (cast v to SubClassA).performTransform(); } That will ensure that we only call performTransform() on v's that are instances of SubClassA. That's a pretty inelegant solution to my eyes, but at least its safe. I have used interface based polymorphism (interface meaning a type that can't be instantiated and defines the API of classes that implement it) in the past, but that also feels clunky. For the above case, if SubClassA and SubClassB implemented ISuperClass that defined performTransform, then they would both have to implement performTransform(). If SubClassB had no real need for a performTransform() you would have to implement an empty function. There must be a design pattern out there that addresses the issue.

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  • Dealing with Expression Blend's lack of support for C++/CLI projects

    - by Brian Ensink
    I have a WPF C# project that references a C++/CLI mixed mode project. I'm having trouble using the WPF project in Expression Blend 3. I'm new to Blend so perhaps this is obvious, but it won't display the xaml designer properly until it builds the project. In my case it complains that my custom commands are not "recognized or accessible" and the solution is to build the project in Blend. But I can't build the project because it references a C++/CLI mixed mode project which Blend won't load. The WPF project is pure C# it just happens to reference a C++/CLI mixed mode project but I'm not asking Blend to do anything with the mixed-mode assembly. How can I work around this problem? Edit: I was able to get it to build by removing the reference to the C++/CLI mixed mode project and replacing it with a reference to the actual assembly. However this is not ideal because in my past experience Visual Studio will not always be able to resolve the reference when switching between release and debug configurations.

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  • Matlab fft function

    - by CTZStef
    The code below is from the Matlab 2011a help about fft function. I think there is a problem here : why do they multiply t(1:50) by Fs, and then say it's time in millisecond ? Certainly, it happens to be true in this very particular case, but change the value of Fs to, say, 2000, and it won't work anymore, obviously because of this factor of 2. Right ? Quite misleading, isn't it ? What do I miss ? Fs = 1000; % Sampling frequency T = 1/Fs; % Sample time L = 1000; % Length of signal t = (0:L-1)*T; % Time vector % Sum of a 50 Hz sinusoid and a 120 Hz sinusoid x = 0.7*sin(2*pi*50*t) + sin(2*pi*120*t); y = x + 2*randn(size(t)); % Sinusoids plus noise plot(Fs*t(1:50),y(1:50)) title('Signal Corrupted with Zero-Mean Random Noise') xlabel('time (milliseconds)') Clearer with this : fs = 2000; % Sampling frequency T = 1 / fs; % Sample time L = 1000; % Length of signal t2 = (0:L-1)*T; % Time vector f = 50; % signal frequency s2 = sin(2*pi*f*t2); figure, plot(fs*t2(1:50),s2(1:50)); % NOT good figure, plot(t2(1:50),s2(1:50)); % good

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  • Prawn image position

    - by John
    I'm trying to layout 6 images per page with prawn in Ruby: case (idx % 6) # ugly when 0 : (pdf.start_new_page; pdf.image img, :position => :left, :vposition => :top, :width => 270) when 1 : pdf.image img, :position => :right, :vposition => :top, :width => 270 when 2 : pdf.image img, :position => :left, :vposition => :center, :width => 270 when 3 : pdf.image img, :position => :right, :vposition => :center, :width => 270 when 4 : pdf.image img, :position => :left, :vposition => :bottom, :width => 270 when 5 : pdf.image img, :position => :right, :vposition => :bottom, :width => 270 end Not sure what I'm doing wrong, but it prints the first 3 images to the PDF, then creates a new page and prints the last three: Page 1: <img> <img> <blank> <blank> <blank> <blank> Page 2: <blank> <blank> <blank> <img> <img> <img> Any suggestions would help.

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  • Custom authentication module inheriting IHttpModule issue.

    - by Chandan Khatwani
    LoginPage.aspx:- protected void Button1_Click(object sender, EventArgs e) { Context.Items["Username"] = txtUserId.Text; Context.Items["Password"] = txtPassword.Text; // FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(1, Context.Items["Username"].ToString(), DateTime.Now, DateTime.Now.AddMinutes(10), true, "users", FormsAuthentication.FormsCookiePath); // Encrypt the cookie using the machine key for secure transport string hash = FormsAuthentication.Encrypt(ticket); HttpCookie cookie = new HttpCookie( FormsAuthentication.FormsCookieName, // Name of auth cookie hash); // Hashed ticket // Set the cookie's expiration time to the tickets expiration time if (ticket.IsPersistent) cookie.Expires = ticket.Expiration; Response.Cookies.Add(cookie); Response.Redirect("Default.aspx"); } Global.asax file:- void Application_AuthenticateRequest(object sender, EventArgs e) { if (HttpContext.Current.User != null) { if (HttpContext.Current.User.Identity.IsAuthenticated) { if (HttpContext.Current.User.Identity is FormsIdentity) { FormsIdentity id = (FormsIdentity)HttpContext.Current.User.Identity; FormsAuthenticationTicket ticket = id.Ticket; // Get the stored user-data, in this case, our roles string userData = ticket.UserData; string[] roles = userData.Split(','); HttpContext.Current.User = new System.Security.Principal.GenericPrincipal(id, roles); Response.Write(HttpContext.Current.User.Identity.Name); Response.Redirect("Default.aspx"); } } } } I get the following error after signing in This webpage has a redirect loop. The webpage at http://localhost:1067/Default.aspx has resulted in too many redirects. Clearing your cookies for this site or allowing third-party cookies may fix the problem. If not, it is possibly a server configuration issue and not a problem with your computer.

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  • Returning JSON object from an ASP.NET page

    - by Emin
    Hi, In my particular situation, I have couple of solutions to my problem. I want to find out which one is more feasible. In this case, I can also achieve my goal by returning a JSON object from my server side code, however, I do not know how it is done and what is the best way of doing it. First off, I don't need a full aspx page as I only need a response returned from code. So, do I use web services? handler? or is there any other specific way you people do this? Is this solution feasible? do I build the JSON string using the StringBuilder class and inject that string into the target aspx page? are there any precautions? or things that I should be aware of? I appreciate your ideas. Regards, Kemal ------------UPDATE !------------ Suppose I have a JSON object in my userlist.aspx page. which then I use it with jQuery... {"menu": { "id": "color1", "value": "color", "popup": { "menuitem": [ {"value": "Red"}, {"value": "Green"}, {"value": "Yellow"} ] } }} // example taken from the json.org/example page now when I want to add a new menuitem from my aspx page, what do I do... I think this way my question is more specific... Lets assume I create a new string in my aspx code, as such "{"value": "Blue"}. Now how do I inject this into the already existing itemlist in the target page? or is this not the correct approach to this kind of situation? if not how else can it be achieved? Also if I wanted to fire a jquery event when a new item is added to this list, how is this achieved?

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  • Is there really such a thing as "being good at math"?

    - by thezhaba
    Aside from gifted individuals able to perform complex calculations in their head, I'm wondering if proficiency in mathematics, namely calculus and algebra, has really got to do with one's natural inclination towards sciences, if you can put it that way. A number of students in my calculus course pick up material in seemingly no time whereas I, personally, have to spend time thinking about and understanding most concepts. Even then, if a question that requires a bit more 'imagination' comes up I don't always recognize the concepts behind it, as is the case with calculus proofs, for instance. Nevertheless, I refuse to believe that I'm simply not made for it. I do very well in programming and software engineering courses where a lot of students struggle. At first I could not grasp what they found to be so difficult, but eventually I realized that having previous programming experience is a great asset -- once I've seen and made practical use of the programming concepts learning about them in depth in an academic setting became much easier as I have then already seen their use "in the wild". I suppose I'm hoping that something similar happens with mathematics -- perhaps once the practical idea behind a concept (which authors of textbooks sure do a great job of concealing..) is evident, understanding the seemingly dry and symbolic ideas and proofs would be more obvious? I'm really not sure. All I'm sure of is I'd like to get better at calculus, but I don't yet understand why some of us pick it up easily while others have to spend considerable amounts of time on it and still not have complete understanding if an unusual problem is given.

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  • C#: HTTPWebResponse using application/x-www-form-urlencoded

    - by CSharpened
    So I sent an HTTPWebRequest using application/x-www-form-urlencoded as my content type. I assume that this means the reponse will be returned in a similar type? (EDIT: Have now been told this isn't the case) My question is this. How do I access the different key/value pairs returned in the response. My code so far looks like this. I can of course read the string but surely there is a better way to access the data other than ripping the string apart. HttpWebResponse response = SendPOSTRequest("https://site/page?Service=foo", content.ToString(), "", "", true); string responseCode = response.StatusCode.ToString(); string responseStatusDescription = response.StatusDescription; StreamReader sr = new StreamReader(response.GetResponseStream()); string result = sr.ReadToEnd(); I tried using XML/linq to read the elements into an XDocument but of course it is not being returned in XML form. Assume I have 3 or 4 different pieces of information in there how could I read them out? EDIT: I have just checked and the data is being returned as text/plain. How can this be processed easily? EDIT: The response string once retrieved via a streamreader is: VPSProtocol=2.23 Status=OK StatusDetail=Server transaction registered successfully. VPSTxId={FDC93F3D-FC64-400D-875F-0B7E855AD81F} SecurityKey=***** NextURL=https://foo.com/PaymentPage.asp?TransactionID={875F-0B7E855AD81F}

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  • Data Warehouse: Modelling a future schedule

    - by Pat
    I'm creating a DW that will contain data on financial securities such as bonds and loans. These securities are associated with payment schedules. For example, a bond could pay quarterly, while a mortage would usually pay monthly (sometimes biweekly). The payment schedule is created when the security is traded and, in the majority of cases, will remain unchanged. However, the design would need to accomodate those cases where it does change. I'm currently attempting to model this data and I'm having difficulty coming up with a workable design. One of the most commonly queried fields is "next payment date". Users often want to know when a security will pay next. Therefore, I want to make it as easy as possible for them to get the next payment date and amount for each security. Also, users often run historical queries in which case they'd want the next payment date and amount as of a specific point in time. For example, they may want to look back at 1/31/09 and query the next payment dates (which would usually be in February 2009 for mortgages). It's also common that they want to query a security's entire payment schedule, which might consist of 360 records (30 year mortgage x 12 payments/year). Since the next payment date and amount would be changing each month or even biweekly, these fields wouldn't seem to fit into a slow-changing dimension very well. It would probably make more sense to use a fact table, but I'm unsure of how to model it. Any ideas would be greatly appreciated.

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  • Where can I get software-related legal advice?

    - by musicfreak
    Whenever someone asks a legal question here on SO, the response is usually something along the lines of "we are not lawyers." Okay, that's legitimate, but in that case, how can I talk to a lawyer about software-related legal matters? I could look through the phone book and find a local lawyer, but then I have no way of knowing whether the lawyer knows anything about software. (And I hear most local lawyers charge for your time, even if it's just a simple question.) Is there maybe some kind of online service for this sort of thing? For now, I'm just looking for some basic advice, so something free would be awesome, even if the "quality" is not as good. However, I'll still take any kind of paid services--I'll keep them in mind for the future. You can give me anything from a forum or QA site (like this one) to a professional service. Just remember that I'm looking specifically for software-related legal advice. I'm sure most lawyers know a thing or two about software, but I'd rather talk to someone who legitimately knows his stuff than someone who can only guess.

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  • emacs: How to intelligently handle buffer-modified when setting text properties?

    - by Cheeso
    The documentation on Text Properties says: Since text properties are considered part of the contents of the buffer (or string), and can affect how a buffer looks on the screen, any change in buffer text properties marks the buffer as modified. First, I don't understand that policy. Can anyone explain? The text props are not actually saved in the file, when the buffer is saved. So why mark the buffer as modified? For me, buffer-modified indicates "some changes have not yet been saved." but understanding the policy is just for my own amusement. More importantly, is there an already-established way that, in code, I can change syntax text properties on the text in a buffer, while keeping the buffer-modified flag set to whatever it was, prior to those changes? I'm thinking of something like save-excursion. It would be pretty easy to write, but this seems like a common case and I'd like to use the standard function, if possible. For more on the scenario - I have a mode that does a full text scan and sets syntax-tabe properties on the text. After opening a buffer, the scan runs, but it results in a buffer with buffer-modified set to t . As always, thanks.

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  • Can't store UTF-8 in RDS despite setting up new Parameter Group using Rails on Heroku

    - by Lail
    I'm setting up a new instance of a Rails(2.3.5) app on Heroku using Amazon RDS as the database. I'd like to use UTF-8 for everything. Since RDS isn't UTF-8 by default, I set up a new Parameter Group and switched the database to use that one, basically per this. Seems to have worked: SHOW VARIABLES LIKE '%character%'; character_set_client utf8 character_set_connection utf8 character_set_database utf8 character_set_filesystem binary character_set_results utf8 character_set_server utf8 character_set_system utf8 character_sets_dir /rdsdbbin/mysql-5.1.50.R3/share/mysql/charsets/ Furthermore, I've successfully setup Heroku to use the RDS database. After rake db:migrate, everything looks good: CREATE TABLE `comments` ( `id` int(11) NOT NULL AUTO_INCREMENT, `commentable_id` int(11) DEFAULT NULL, `parent_id` int(11) DEFAULT NULL, `content` text COLLATE utf8_unicode_ci, `child_count` int(11) DEFAULT '0', `created_at` datetime DEFAULT NULL, `updated_at` datetime DEFAULT NULL, PRIMARY KEY (`id`), KEY `commentable_id` (`commentable_id`), KEY `index_comments_on_community_id` (`community_id`), KEY `parent_id` (`parent_id`) ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; In the markup, I've included: <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> Also, I've set: production: encoding: utf8 collation: utf8_general_ci ...in the database.yml, though I'm not very confident that anything is being done to honor any of those settings in this case, as Heroku seems to be doing its own config when connecting to RDS. Now, I enter a comment through the form in the app: "Úbe® ƒåiL", but in the database I've got "Úbe® Æ’Ã¥iL" It looks fine when Rails loads it back out of the database and it is rendered to the page, so whatever it is doing one way, it's undoing the other way. If I look at the RDS database in Sequel Pro, it looks fine if I set the encoding to "UTF-8 Unicode via Latin 1". So it seems Latin-1 is sneaking in there somewhere. Somebody must have done this before, right? What am I missing?

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  • Most efficient way to LIMIT results in a JOIN?

    - by johnnietheblack
    I have a fairly simple one-to-many type join in a MySQL query. In this case, I'd like to LIMIT my results by the left table. For example, let's say I have an accounts table and a comments table, and I'd like to pull 100 rows from accounts and all the associated comments rows for each. Thy only way I can think to do this is with a sub-select in in the FROM clause instead of simply selecting FROM accounts. Here is my current idea: SELECT a.*, c.* FROM (SELECT * FROM accounts LIMIT 100) a LEFT JOIN `comments` c on c.account_id = a.id ORDER BY a.id However, whenever I need to do a sub-select of some sort, my intermediate level SQL knowledge feels like it's doing something wrong. Is there a more efficient, or faster, way to do this, or is this pretty good? By the way... This might be the absolute simplest way to do this, which I'm okay with as an answer. I'm simply trying to figure out if there IS another way to do this that could potentially compete with the above statement in terms of speed.

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  • Codeigniter/mySQL question. Checking if several inserts are possible before actual insertion.

    - by Ethan
    Hey SO, So I'm trying to perform a couple inserts at once that are kind of co-dependent on each other. Let's say I'm doing a dog rating website. Anyone can add a dog to my database, but in doing so they also need to add a preliminary rating of the dog. Other people can then rate the dog afterwards. The dogs to ratings is a many to one relationship: a dog has many ratings. This means for my preliminary add, since I have the person both rate and add the dog, I need to take the rating, and set a foreign key to the dog's primary key. As far as I know, this means I have to actually add the dog, then check what that new addition's primary key is, and then put that in my rating before insertion. Now suppose something were to go wrong with the rating's insert, be it a string that's too long, or something that I've overlooked somehow. If the rating's failed, the dog has already been inserted, but the rating has not. In this case, I'd like the dog to not have been added in the first place. Does this mean I have to write code that says "if the rating fails, do a remove for the dog," or is there a way to predict what the key will be for the dog should everything go as planned. Is there a way to say "hold that spot," and then if everything works, add it? Any help would be greatly appreciated. Thanks!!

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  • Using stringstream instead of `sscanf` to parse a fixed-format string

    - by John Dibling
    I would like to use the facilities provided by stringstream to extract values from a fixed-format string as a type-safe alternative to sscanf. How can I do this? Consider the following specific use case. I have a std::string in the following fixed format: YYYYMMDDHHMMSSmmm Where: YYYY = 4 digits representing the year MM = 2 digits representing the month ('0' padded to 2 characters) DD = 2 digits representing the day ('0' padded to 2 characters) HH = 2 digits representing the hour ('0' padded to 2 characters) MM = 2 digits representing the minute ('0' padded to 2 characters) SS = 2 digits representing the second ('0' padded to 2 characters) mmm = 3 digits representing the milliseconds ('0' padded to 3 characters) Previously I was doing something along these lines: string s = "20101220110651184"; unsigned year = 0, month = 0, day = 0, hour = 0, minute = 0, second = 0, milli = 0; sscanf(s.c_str(), "%4u%2u%2u%2u%2u%2u%3u", &year, &month, &day, &hour, &minute, &second, &milli ); The width values are magic numbers, and that's ok. I'd like to use streams to extract these values and convert them to unsigneds in the interest of type safety. But when I try this: stringstream ss; ss << "20101220110651184"; ss >> setw(4) >> year; year retains the value 0. It should be 2010. How do I do what I'm trying to do? I can't use Boost or any other 3rd party library, nor can I use C++0x.

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  • Stop NSXMLParser Instance from Causing _NSAutoreleaseNoPool

    - by PF1
    Hi Everyone: In my iPhone application, I have an instance of NSXMLParser that is set to a custom delegate to read the XML. This is then moved into its own thread so it can update the data in the background. However, ever since I have done this, it has been giving me a lot of _NSAutoreleaseNoPool warnings in the console. I have tried to add a NSAutoreleasePool to each of my delegate classes, however, this hasn't seemed to solve the problem. I have included my method of creating the NSXMLParser in case that is at fault. NSURL *url = [[NSURL alloc] initWithString:@"http://www.mywebsite.com/xmlsource.xml"]; NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithContentsOfURL:url]; CustomXMLParser *parser = [[CustomXMLParser alloc] init]; parser.managedObjectContext = self.managedObjectContext; parser = [parser initXMLParser]; [xmlParser setDelegate:parser]; [NSThread detachNewThreadSelector:@selector(parse) toTarget:xmlParser withObject:nil]; If anyone has any ideas to get rid of this problem, I would really appreciate it. Thanks.

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  • How to write these two queries for a simple data warehouse, using ANSI SQL?

    - by morpheous
    I am writing a simple data warehouse that will allow me to query the table to observe periodic (say weekly) changes in data, as well as changes in the change of the data (e.g. week to week change in the weekly sale amount). For the purposes of simplicity, I will present very simplified (almost trivialized) versions of the tables I am using here. The sales data table is a view and has the following structure: CREATE TABLE sales_data ( sales_time date NOT NULL, sales_amt double NOT NULL ) For the purpose of this question. I have left out other fields you would expect to see - like product_id, sales_person_id etc, etc, as they have no direct relevance to this question. AFAICT, the only fields that will be used in the query are the sales_time and the sales_amt fields (unless I am mistaken). I also have a date dimension table with the following structure: CREATE TABLE date_dimension ( id integer NOT NULL, datestamp date NOT NULL, day_part integer NOT NULL, week_part integer NOT NULL, month_part integer NOT NULL, qtr_part integer NOT NULL, year_part integer NOT NULL, ); which partition dates into reporting ranges. I need to write queries that will allow me to do the following: Return the change in week on week sales_amt for a specified period. For example the change between sales today and sales N days ago - where N is a positive integer (N == 7 in this case). Return the change in change of sales_amt for a specified period. For in (1). we calculated the week on week change. Now we want to know how that change is differs from the (week on week) change calculated last week. I am stuck however at this point, as SQL is my weakest skill. I would be grateful if an SQL master can explain how I can write these queries in a DB agnostic way (i.e. using ANSI SQL).

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  • Move SELECT to SQL Server side

    - by noober
    Hello all, I have an SQLCLR trigger. It contains a large and messy SELECT inside, with parts like: (CASE WHEN EXISTS(SELECT * FROM INSERTED I WHERE I.ID = R.ID) THEN '1' ELSE '0' END) AS IsUpdated -- Is selected row just added? as well as JOINs etc. I like to have the result as a single table with all included. Question 1. Can I move this SELECT to SQL Server side? If yes, how to do this? Saying "move", I mean to create a stored procedure or something else that can be executed before reading dataset in while cycle. The 2 following questions make sense only if answer is "yes". Why do I want to move SELECT? First off, I don't like mixing SQL with C# code. At second, I suppose that server-side queries run faster, since the server have more chances to cache them. Question 2. Am I right? Is it some sort of optimizing? Also, the SELECT contains constant strings, but they are localizable. For instance, WHERE R.Status = "Enabled" "Enabled" should be changed for French, German etc. So, I want to write 2 static methods -- OnCreate and OnDestroy -- then mark them as stored procedures. When registering/unregistering my assembly on server side, just call them respectively. In OnCreate format the SELECT string, replacing {0}, {1}... with required values from the assembly resources. Then I can localize resources only, not every script. Question 3. Is it good idea? Is there an existing attribute to mark methods to be executed by SQL Server automatically after (un)registartion an assembly? Regards,

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  • SPSS - sum of squares change radically with slight model changes in ANOVA??

    - by Pat
    I have noticed that the sum of squares in my models can change fairly radically with even the slightest adjustment to my models???? Is this normal???? I'm using SPSS 16, and both models presented below used the same data and variables with only one small change - categorizing one of the variables as either a 2 level or 3 level variable. Details - using a 2 x 2 x 6 mixed model ANOVA with the 6 being the repeated measure i get the following in the between group analysis ------------------------------------------------------------ Source | Type III SS | df | MS | F | Sig ------------------------------------------------------------ intercept | 4086.46 | 1 | 4086.46 | 104.93 | .000 X | 224.61 | 1 | 224.61 | 5.77 | .019 Y | 2.60 | 1 | 2.60 | .07 | .80 X by Y | 19.25 | 1 | 19.25 | .49 | .49 Error | 2570.40 | 66 | 38.95 | Then, when I use the exact same data but a slightly different model in which variable Y has 3 levels instead of 2 levels I get the following ------------------------------------------------------------ Source | Type III SS | df | MS | F | Sig ------------------------------------------------------------ intercept | 3603.88 | 1 | 3603.88 | 90.89 | .000 X | 171.89 | 1 | 171.89 | 4.34 | .041 Y | 19.23 | 2 | 9.62 | .24 | .79 X by Y | 17.90 | 2 | 17.90 | .80 | .80 Error | 2537.76 | 64 | 39.65 | I don't understand why variable X would have a different sum of squares simply because variable Y gets devided up into 3 levels instead of 2. This is also the case in the within groups analysis too. Please help me understand :D Thank you in advance Pat

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  • What about parallelism across network using multiple PCs?

    - by MainMa
    Parallel computing is used more and more, and new framework features and shortcuts make it easier to use (for example Parallel extensions which are directly available in .NET 4). Now what about the parallelism across network? I mean, an abstraction of everything related to communications, creation of processes on remote machines, etc. Something like, in C#: NetworkParallel.ForEach(myEnumerable, () => { // Computing and/or access to web ressource or local network database here }); I understand that it is very different from the multi-core parallelism. The two most obvious differences would probably be: The fact that such parallel task will be limited to computing, without being able for example to use files stored locally (but why not a database?), or even to use local variables, because it would be rather two distinct applications than two threads of the same application, The very specific implementation, requiring not just a separate thread (which is quite easy), but spanning a process on different machines, then communicating with them over local network. Despite those differences, such parallelism is quite possible, even without speaking about distributed architecture. Do you think it will be implemented in a few years? Do you agree that it enables developers to easily develop extremely powerfull stuff with much less pain? Example: Think about a business application which extracts data from the database, transforms it, and displays statistics. Let's say this application takes ten seconds to load data, twenty seconds to transform data and ten seconds to build charts on a single machine in a company, using all the CPU, whereas ten other machines are used at 5% of CPU most of the time. In a such case, every action may be done in parallel, resulting in probably six to ten seconds for overall process instead of forty.

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  • [C#]How to introduce retry logic into LINQ to SQL to deal with timeouts?

    - by codemonkie
    I need to find ways to add retry mechanism to my DB calls in case of timeouts, LINQ to SQL is used to call some sprocs in my code... using (MyDataContext dc = new MyDataContext()) { int result = -1; //denote failure int count = 0; while ((result < 0) && (count < MAX_RETRIES)) { result = dc.myStoredProc1(...); count++; } result = -1; count = 0; while ((result < 0) && (count < MAX_RETRIES)) { result = dc.myStoredProc2(...); count++; } ... ... } Not sure if the code above is right or posed any complications. It'll be nice to throw an exception after MAX_RETRIES has reached, but I dunno how and where to throw them appropriately :-) Any helps appreciated.

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  • Four-color theorem in Prolog (using a dynamic predicate)

    - by outa
    Hi, I'm working on coloring a map according to the four-color theorem (http://en.wikipedia.org/wiki/Four_color_theorem) with SWI-Prolog. So far my program looks like this: colour(red). colour(blue). map_color(A,B,C) :- colour(A), colour(B), colour(C), C \= B, C \= A. (the actual progam would be more complex, with 4 colors and more fields, but I thought I'd start out with a simple case) Now, I want to avoid double solutions that have the same structure. E.g. for a map with three fields, the solution "red, red, blue" would have the same structure as "blue, blue, red", just with different color names, and I don't want both of them displayed. So I thought I would have a dynamic predicate solution/3, and call assert(solution(A,B,C)) at the end of my map_color predicate. And then, for each solution, check if they already exist as a solution/3 fact. The problem is that I would have to assert something like solution(Color1,Color1,Color2), i.e. with variables in order to make a unification check. And I can't think of a way to achieve this. So, the question is, what is the best way to assert a found solution and then make a unification test so that "red, red, blue" would unify with "blue, blue, red"?

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  • Why does my DIV clip its child DIV when jQuery moves it in IE?

    - by Ben Saufley
    I have two divs, both with position:absolute;, one inside the other. The parent isn't in a place where it can be set as position:relative without an extra layer of complexity (there are a lot of other elements around it that I'd have to account for to put it where it needs to be, which is at the very top of the page, over everything). The child element is made to stick off the bottom of the parent. In Chrome, Safari, Firefox, it all works splendidly. In IE, it works until jQuery moves the parent element - at which point the parent element clips the child, so you can barely see the top of the child. I feel like I've read about this, about IE clipping child elements, but I can't seem to find an answer that applies to my case. It's pretty simple, basically: <div id="parent" style="position:absolute;top:0;left:0;"> [content] <div id="tab" style="position:absolute;bottom:-30px;left:0;width:64px;height:32px;background-image:(...);"></div> </div> <script> $(document).ready( function() { $("#tab").click(function() { $("#parent").animate({"top":"-50px"},300); }); }); </script>

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  • Regular Expressions .NET

    - by Fosa
    I need a regular expression for some arguments that must match on a string. here it is... The string exists out of minimum 8 en maximum 20 characters. These characters of this string may be characters of the alfabet or special chars --With other words..all charachters except from the whitespaces In the complete string there must be atleast 1 number. The string cannot start with a number or an underscore The last 2 characters of the string must be identical, But it doenst matter if those last --identical characters are capital or non-capital (case insensitive) Must match all : +234567899 a_1de*Gg xy1Me*__ !41deF_hij2lMnopq3ss C234567890123$^67800 *5555555 sDF564zer"" !!!!!!!!!4!!!!!!!!!! abcdefghijklmnopq9ss May not match : Cannot be less then 8 or more then 20 chars: a_1+Eff B41def_hIJ2lmnopq3stt Cannot contain a whitespace: A_4 e*gg b41def_Hij2l nopq3ss Cannot start with a number or an underscore: __1+Eff 841DEf_hij2lmnopq3stt cannot end on 2 diffrent characters: a_1+eFg b41DEf_hij2lmnopq3st Cannot be without a number in the string: abCDefghijklmnopqrss abcdef+++dF !!!!!!!!!!!!!!!!!!!! ------------------------------------------------------ This is what I have so far...But I'm really breaking my head on this... If you Don't know the answer completely it's not a problem... I just want to get in the right direction ([^0-9_])(?=.*\d)(\S{8,20})(?i:[\S])\1

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