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  • Unable to persist objects in GAE JDO

    - by Basil Dsouza
    Hello Guys, I am completely fresh to both JDO and GAE, and have been struggling to get my data layer to persist any code at all! The issues I am facing may be very simple, but I just cant seem to find any a way no matter what solution I try. Firstly the problem: (Slightly simplified, but still contains all the info necessary) My data model is as such: User: (primary key) String emailID String firstName Car: (primary key) User user (primary key) String registration String model This was the initial datamodel. I implemented a CarPK object to get a composite primary key of the User and the registration. However that ran into a variety of issues. (Which i will save for another time/question) I then changed the design as such: User: (Unchanged) Car: (primary key) String fauxPK (here fauxPK = user.getEmailID() + SEP + registration) User user String registration String model This works fine for the user, and it can insert and retrieve user objects. However when i try to insert a Car Object, i get the following error: "Cannot have a java.lang.String primary key and be a child object" Found the following helpful link about it: http://stackoverflow.com/questions/2063467/persist-list-of-objects Went to the link suggested there, that explains how to create Keys, however they keep talking about "Entity Groups" and "Entity Group Parents". But I cant seem to find any articles or sites that explain what are "Entity Group"s or an "Entity Group Parents" I could try fiddling around some more to figure out if i can store an object somehow, But I am running sort on patience and also would rather understand and implement than vice versa. So i would appreciate any docs (even if its huge) that covers all these points, and preferably has some examples that go beyond the very basic data modeling. And thanks for reading such a long post :)

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  • Interchange structured data between Haskell and C

    - by Eonil
    First, I'm a Haskell beginner. I'm planning integrating Haskell into C for realtime game. Haskell does logic, C does rendering. To do this, I have to pass huge complexly structured data (game state) from/to each other for each tick (at least 30 times per second). So the passing data should be lightweight. This state data may laid on sequential space on memory. Both of Haskell and C parts should access every area of the states freely. In best case, the cost of passing data can be copying a pointer to a memory. In worst case, copying whole data with conversion. I'm reading Haskell's FFI(http://www.haskell.org/haskellwiki/FFICookBook#Working_with_structs) The Haskell code look specifying memory layout explicitly. I have a few questions. Can Haskell specify memory layout explicitly? (to be matched exactly with C struct) Is this real memory layout? Or any kind of conversion required? (performance penalty) If Q#2 is true, Any performance penalty when the memory layout specified explicitly? What's the syntax #{alignment foo}? Where can I find the document about this? If I want to pass huge data with best performance, how should I do that? *PS Explicit memory layout feature which I said is just C#'s [StructLayout] attribute. Which is specifying in-memory position and size explicitly. http://www.developerfusion.com/article/84519/mastering-structs-in-c/ I'm not sure Haskell has matching linguistic construct matching with fields of C struct.

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  • How to Load external Div that has a dynamic content using ajax and jsp/servlets ?

    - by A.S al-shammari
    I need to use ajax feature to load external div element ( external jsp file) into the current page. That JSP page contains a dynamic content - e.g. content that is based on values received from the current session. I solved this problem , but I'm in doubt because I think that my solution is bad , or maybe there is better solution since I'm not expert. I have three files: Javascript function that is triggered when a element is clicked, it requests html data from a servlet: $("#inboxtable tbody tr").click(function(){ var trID = $(this).attr('id'); $.post("event?view=read",{id:trID}, function(data){ $("#eventContent").html(data); // load external file },"html"); // type }); The servlet "event" loads the data and generates HTML content using include method : String id = request.getParameter("id"); if (id != null) { v.add("Test"); v.add(id); session.setAttribute("readMessageVector", v); request.getRequestDispatcher("readMessage.jsp").include(request, response); } The readMessage jsp file looks like this: <p> Text: ${readMessageVector[0]} </p> <p> ID: ${readMessageVector[1]} </p> My questions Is this solution good enough to solve this problem - loading external jsp that has dynamic content ? Is there better solution ?

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  • Skipping the BufferedReader readLine() method in java

    - by DDP
    Is there a easy way to skip the readLine() method in java if it takes longer than, say, 2 seconds? Here's the context in which I'm asking this question: public void run() { boolean looping = true; while(looping) { for(int x = 0; x<clientList.size(); x++) { try { Comm s = clientList.get(x); String str = s.recieve(); // code that does something based on the string in the line above } // other stuff like catch methods } } } Comm is a class I wrote, and the receive method, which contains a BufferedReader called "in", is this: public String recieve() { try { if(active) return in.readLine(); } catch(Exception e) { System.out.println("Comm Error 2: "+e); } return ""; } I've noticed that the program stops and waits for the input stream to have something to read before continuing. Which is bad, because I need the program to keep looping (as it loops, it goes to all the other clients and asks for input). Is there a way to skip the readLine() process if there's nothing to read? I'm also pretty sure that I'm not explaining this well, so please ask me questions if I'm being confusing.

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  • Web development scheme for staging and production servers using Git Push

    - by ServAce85
    I am using git to manage a dynamic website (PHP + MySQL) and I want to send my files from my localhost to my staging and development servers in the most efficient and hassle-free way. I am currently convinced that the best way for me to approach this problem is to use this git branching model to organize my local git repo. From there, I will use the release branches to push to my staging server for testing. Once I am happy that the release code works on the staging server, I can then merge with my master branch and push that to my production server. Pushing to Staging Server: As noted in many introductory git posts, I could run into problems pushing into a non-bare repo, so, as suggested in this response, I plan to push the release branch to a bare repo on the server and have a post-receive hook that clones the bare repo to a non-bare repo that also acts as the web-hosted directory. Pushing to Production Server: Here's my newest source of confusion... In the response that I cited above, it made me curious as to why @Paul states that it's a completely different story when pushing to a live, development server. I guess I don't see the problem. Would it be safe and hassle-free to follow the same steps as above, but for the master branch? Where are the potential pit-falls? Config Files: With respect to configuration files that are unique to each environment (.htaccess, config.php, etc), it seems simplest to .gitignore each of those files in their respective repos on their respective servers. Can you see anything immediately wrong with this? Better solutions? Accessing Data: Finally, as I initially stated, the site uses MySQL databases to store data. How would you suggest I access that data (for testing purposes) from the staging server and localhost? I realize that I may have asked way too many questions for a single post, but since they're all related to the best way to set up this development scheme, I thought it was necessary.

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  • How to remove a specific category on a selected mail in Outlook 2003 with Macro?

    - by szekelya
    Hi, I am trying to transform my Outlook2003 into the closest thing to gmail. I started to use categories, which are pretty similar to labels in gmail. I can assign categories automatically with rules, and I can add categories manually. I have also created "search folders", that show all mails with a given category, if they are not in the Deleted Items or Sent Items folders. This part is almost like the Label views in gmail. Two things are missing basically, which should be done with macros (VBA to be precise) which I'm totally inexperienced with. So hence my questions: -Can someone show me a macro to remove the category "Inbox"? That would act exactly like the Archive button in gmail. In fact I want to assign this macro to a toolbar button and call it Archive. I have a rule that adds the Inbox category to all incoming mail. As I said, I have a search folder displaying all mails categorized as Inbox, and I also have an All Mail search folder, that displays all messages regardless whether they have the Inbox category. Exactly like gmail, just the easy archiving is missing. -Can someone show me a macro that would delete the selected mail/mails and also would remove the Inbox category before deletion? I would replace the default delete button with this macro. (Somewhat less important, as in my search folders I can filter messages that are physically placed in the Deleted Items folder, but it would be more elegant not to have mails categorized as Inbox in the trash. Many thanks in advance, szekelya

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  • Grails g:paginate tag and custom URL

    - by aboxy
    Hello, I am trying to use g:paginate in a shared template where depending on the controller, url changes e.g. For my homepage url should be : mydomain[DOT]com/news/recent/(1..n) For search Page: www[DOT]mydomain[DOT]com/search/query/"ipad apps"/filter/this month and my g:paginate looks like this: g:paginate controller=${customeController} action=${customAction} total:${total} For the first case, I was able to provide controller as 'news' and action as 'recent' and mapped url /news/recent/$offset to my controller. But for the search page, I am not able to achieve what I want to do. I have a URL mapping defined as /search/$filter**(controller:"search",action:"fetch") $filter can be /query/"ipad apps"/filter/thismonth/filter/something/filter/somethingelse. I want to be able to show the url as above rather than ?query="ipad apps"&filter=thismonth&filter=something&filter=somethingelse. I believe I can pass all the parameters in params attribute of g:paginate but that will not give me pretty URL. What would be the best way to achieve this? Please feel free to ask questions If i missed anything.Thanks in advance.

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  • Common Lisp condition system for transfer of control

    - by Ken
    I'll admit right up front that the following is a pretty terrible description of what I want to do. Apologies in advance. Please ask questions to help me explain. :-) I've written ETLs in other languages that consist of individual operations that look something like: // in class CountOperation IEnumerable<Row> Execute(IEnumerable<Row> rows) { var count = 0; foreach (var row in rows) { row["record number"] = count++; yield return row; } } Then you string a number of these operations together, and call The Dispatcher, which is responsible for calling Operations and pushing data between them. I'm trying to do something similar in Common Lisp, and I want to use the same basic structure, i.e., each operation is defined like a normal function that inputs a list and outputs a list, but lazily. I can define-condition a condition (have-value) to use for yield-like behavior, and I can run it in a single loop, and it works great. I'm defining the operations the same way, looping through the inputs: (defun count-records (rows) (loop for count from 0 for row in rows do (signal 'have-value :value `(:count ,count @,row)))) The trouble is if I want to string together several operations, and run them. My first attempt at writing a dispatcher for these looks something like: (let ((next-op ...)) ;; pick an op from the set of all ops (loop (handler-bind ((have-value (...))) ;; records output from operation (setq next-op ...) ;; pick a new next-op (call next-op))) But restarts have only dynamic extent: each operation will have the same restart names. The restart isn't a Lisp object I can store, to store the state of a function: it's something you call by name (symbol) inside the handler block, not a continuation you can store for later use. Is it possible to do something like I want here? Or am I better off just making each operation function explicitly look at its input queue, and explicitly place values on the output queue?

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  • Old dll.config problem !

    - by user313421
    Since 2005 as I googled it's a problem for who needs to read the configuration of an assembly from it's config file "*.dll.config" and Microsoft didn't do anything yet. Story: If you try to read a setting from a class library (plug-in) you fail. Instead the main application domain (EXE which is using the plug-in) config is read and because probably there's not such a config your plug-in will use default setting which is hard-coded when you create it's settings for first time. Any change to .dll.config wouldn't see by your plug-in and you wonder why it's there! If you want to replace it and start searching you may find something like this: http://stackoverflow.com/questions/594298/c-dll-config-file But just some ideas and one line code. A good replacement for built-in config shouldn't read from file system each time we need a config value, so we can store them in memory; Then what if user changes config file ? we need a FileSystemWatcher and we need some design like singleton ... and finally we are at the same point configuration of .NET is except our one's working. It seems MS did everything but forgot why they built the ".dll.config". Since no DLL is gonna execute by itself, they are referenced from other apps (even if used in web) and so why there's such a "*.dll.config" file ? I'm not gonna argue if it's good to have multiple config files or not. It's my design (plug-able components). Finally { After these years, is there any good practice such as a custom setting class to add in each assemly and read from it's own config file ? }

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  • "One or more breakpoints cannot be set and have been disabled. Execution will stop at the beginning

    - by sam
    I set a breakpoint in my code in Visual-C++, but when I run, I see the error mentioned in the title. I know this question has been asked before on Stack Overflow (http://stackoverflow.com/questions/657470/breakpoints-cannot-be-set-and-have-been-disabled-problem), but none of the answers there fully explained the problem I'm seeing. The closest I can see is something about the linker, but I don't understand that - so if someone could explain in more detail that would be great. In my case, I have 2 projects in Visual C++ - the production dsw, and the test code dsw. I have loaded and rebuilt both dsws in debug mode. I want a breakpoint in the production code, which is run via the test scripts. My issue is I get the error message when I run the test code, because the break point is in the production code, which isn't loaded up when the test starts. Near the beginning of the test script there is a mytest_initialize() command. I imagine this goes off and loads up the production dll. Once this line has executed, I can put the breakpoint in my production code and run until I hit it. But it's quite annoying to have to run to this line, set the breakpoint and continue every time I want to run the test. So I think the problem is Visual C++ doesn't realise the two projects are related. Is this a linker issue? What does the linker do and what settings should I change to make this work? Thanks in advance. Apologies if instead I should be appending this question to the existing one, this is my first post so not quite sure how this should work.

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  • Definition of the job titles involved in a software development process.

    - by Rafael Romão
    I have seen many job titles for people involved in a software development process, but never found a consensus about they mean. I know many of them are equivalent, and found some other questions about that here in SO, but I would like to know your definitions and comments about them. I want not only to know if there is really a consensus, but also to know if what I suppose to be a Software Architect, is really a Software Architect, and so on. The job titles I mean are: Developer; System Analyst; Programmer; Analyst Programmer; Software Engineer; Software Architect; Designer; Software Designer; Business Manager; Business Analyst; Program Manager; Project Manager; Development Manager; Tester; Support Analyst; Please, feel free to add more titles to this list in your answers. It would be very helpful.

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  • How to best launch C++ application from web page

    - by JB
    I guess there are two parts to this question, one technical and one best practice for security and doing things "right". I'm working on a little game using C++ / directx but I would like to be able to launch it from a web page by someone clicking on a link on that page. Ideally I would like the first time they clicked for it to launch an installer downloads and installs the game on their machine, and then the next time to launch an application which updates the game from a web site if it's old and then launches it. I have no problems with the expected security popups and questions the first time it runs. I want people to be certain what they are installing and understand what they are doing. But it would be nice if once it is installed they could run it with the minimum of fuss. My question then is what technologies I could use to do this? I'm thinking that it would need a browser plugin and an activex control so that first time you'd install that, and subsequently the control/plugin would be able to launch the game. I'm not sure that under newer browser secuity models that a plugin would have the permissions to be able to run an installer though or silently invoke applications on the client machine even if they are already installed. Is there a more sensible way to achive what I want to achieve? And I'm worried about the security aspects too. I want this to be convenient for users but I of course want to do it "right". I know this can be done as I've seen several mmorpg type games that launch in this way from the browser now but it's not entirely clear to me how they've done it.

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  • curl_multi_exec stops if one url is 404, how can I change that?

    - by Rob
    Currently, my cURL multi exec stops if one url it connects to doesn't work, so a few questions: 1: Why does it stop? That doesn't make sense to me. 2: How can I make it continue? EDIT: Here is my code: $SQL = mysql_query("SELECT url FROM shells") ; $mh = curl_multi_init(); $handles = array(); while($resultSet = mysql_fetch_array($SQL)){ //load the urls and send GET data $ch = curl_init($resultSet['url'] . $fullcurl); //Only load it for two seconds (Long enough to send the data) curl_setopt($ch, CURLOPT_TIMEOUT, 5); curl_multi_add_handle($mh, $ch); $handles[] = $ch; } // Create a status variable so we know when exec is done. $running = null; //execute the handles do { // Call exec. This call is non-blocking, meaning it works in the background. curl_multi_exec($mh,$running); // Sleep while it's executing. You could do other work here, if you have any. sleep(2); // Keep going until it's done. } while ($running > 0); // For loop to remove (close) the regular handles. foreach($handles as $ch) { // Remove the current array handle. curl_multi_remove_handle($mh, $ch); } // Close the multi handle curl_multi_close($mh);

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  • ajax login problem

    - by rdanee
    $(document).ready(function() { $("form#login_form").submit(function() { var login_username = $('#login_username').attr('value'); var login_password = $('#login_password').attr('value'); type: "POST", $.ajax({ url: "login.php", data: "username="+ login_username +"& password="+ login_password, success: function(data){ alert(data); if (data == "ok"){ $('form#login_form').hide(function(){$('div.success').fadeIn();}); } } }); return false; }); Login.php: <?php include("settings.php"); $query = "select * from users where username = '{$_POST['login_username']}' and password = md5('{$_POST['login_password']}')"; $query = mysql_query($query, $connection); if ( mysql_num_rows($query) == 1 ) { print "ok"; $array = mysql_fetch_array($query); if ( $_POST['stay'] ) { $time = time()+2592000; } else { $time = 0; } } else { print "no"; } mysql_close($connection); ?> My problem: In the alert the message always "no" whether username/password is correct, however on the site "ok" appears when username/pw is correct. I have read the other questions in connection with this problem, but I couldn't solve the response problem from login.php with Json. Could you help me how should I response to the ajax calling? ( with a code if it is possible) Thank you very much, and sorry for questioning again.

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  • Paperclip failing to upload on specific scaffold, yet works on others

    - by Saifis
    I know there are tons of questions about paperclip, but I failed to find the answer to my problem. I know its prob just something simple, but I I'm running out of hair to pull out. I have paperclip working on other parts of my project, they work with no problem, however, a certain scaffold fails to upload, all the attributes to the uploaded file are nil. Here are the relevant information. Model: has_attached_file :foo, :styles => { :thumb => "140x140>" }, :url => "/data/:id/:style/:basename.:extension", :path => ":rails_root/public/data/:id/:style/:basename.:extension" View: <% form_for(@bar, :html => { :multipart => true }) do |f| %> <%= f.error_messages %> ---------- <li><%= f.label :top %> <%= f.file_field :foo %></li> ---------- <ul><%= f.submit "Save" %></ul> <% end %> Also, comparing the logs to the parts that work, the :foo attribute seems to be passing different values than in the ones that work. In the logs, when the paperclip function works, it looks like this "image"=>#<File:/var/folders/M5/M5HEb+WhFxmqNDGH5s-pNE+++TI/-Tmp-/RackMultipart20100512-1302-5e2e6e-0> when it does not, it seems to pass the file name directly "foo"=>"foo_image.png" I am developing locally on MacOSX using local rails and ruby libs.

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  • Removing HttpModule for specific path in ASP.NET / IIS 7 application?

    - by soccerdad
    Most succinctly, my question is whether an ASP.NET 4.0 app running under IIS 7 integrated mode should be able to honor this portion of my Web.config file: <location path="auth/windows"> <system.webServer> <modules> <remove name="FormsAuthentication"/> </modules> </system.webServer> </location> I'm experimenting with mixed mode authentication (Windows and Forms - I know there are other questions on S.O. about the topic). Using IIS Manager, I've disabled Anonymous authentication to auth/windows/winauth.aspx, which is within the location path above. I have Failed Request Tracing set up to trace various HTTP status codes, including 302s. When I request the winauth.aspx page, a 302 HTTP status code is returned. If I look at the request trace, I can see that a 401 (unauthorized) was originally generated by the AnonymousAuthenticationModule. However, the FormsAuthenticationModule converts that to a 302, which is what the browser sees. So it seems as though my attempt to remove that module from the pipeline for pages in that path isn't working. But I'm not seeing any complaints anywhere (event viewer, yellow pages of death, etc.) that would indicate it's an invalid configuration. I want the 401 returned to the browser, which presumably would include an appropriate WWW-Authenticate header. A couple of other points: a) I do have <authentication mode="Forms"> in my Web.config, and that is what the 302 redirects to; b) I got the "name" of the module I'm trying to remove from the inetserv\config\applicationHost.config file. Anyone had any luck removing modules in this fashion? Thanks much, Donnie

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  • How do I create Variables in XSLT that are not document fragments?

    - by chiborg
    Consider the following XSLT template <xsl:template match="/"> <xsl:variable name="var1"> <elem>1</elem> <elem>2</elem> <elem>3</elem> </xsl:variable> <xsl:text>var1 has </xsl:text> <xsl:value-of select="count($var1)"/> <xsl:text>elements. </xsl:text> <xsl:variable name="var2" select="$var1/elem[. != '2']"/> <xsl:text>var2 has </xsl:text> <xsl:value-of select="count($var2)"/> <xsl:text>elements. </xsl:text> </xsl:template> The output of this template is var1 has 1 elements var2 has 2 elements The first line outputs 1 (and not, as I first expected 3) because var1 is a document fragment that contains the <elem> elements as childen. Now for my questions: How can I create a variable that does not contain a document fragment? I could do it like I did with var2, only leaving out the predicate. But maybe there is a way without using a second variable. Or, as an alternative: How can I preserve the document fragment in a variable while filtering out some elements?

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  • QT4 Designer - Implement Widget

    - by MOnsDaR
    I'm currently trying to get into QT4 and figure out a workflow for myself. While trying to create a widget which allows the user to connect to a hostname:port some questions appeared. The widget itself contains a LineEdit for entering the hostname, a SpinBox for entering the port and a PushButton which should emit a connect(QString hostname, unsigned int port) signal. In QTDesigner I created the necessary Form. It is saved as a .ui-File. Now the big question is how could I implement the widget? Is there a place in QTDesigner where I could add my signal to the Widget? Where could I add custom Properties? I've learned in another tutorial, which showed how to create a Widget in C++, how signals, slots, Q_PROPERTIES etc are defined and added to the widget. But there is no sourcecode in QTDesigner. Another option would be to generate sourcecode using uic. But the header says, that another generate would overwrite any changes to the sourcefiles. So how can I create a QT-widget completely with my own signals, slots and properties by using the QTDesigner for creating the UI and not having to recode everything whenever the UI is changing. Is there some kind of Roundtrip-Engineering? If thats not possible: Whats the sense of creating a Widget with QTDesigner then?

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  • Career day in kindergarten

    - by Péter Török
    I was invited to the kindergarten group of my elder daughter to talk and answer the kids' questions about my profession. There are 26 kids of age 4-6 in the group, plus 3 teachers who are fairly scared of anything related to programming and IT themselves, but bold enough to learn new tricks. I would have about 20-30 minutes, without projector or anything. They have an old computer though, which by its look may be a 486, and I am not even sure if it's functioning. My research turned up excellent earlier threads, with lots of good tips: How would you explain your job to a 5-year old? Career Day: how do I make “computer programmer” sound cool to 8 year olds? What things can I teach a group of children about programming in one day? My situation is different from each of the above though: the latter ones are concerned with older children, while the first one is about talking to a single kid (or elder person)—a group of 20 is a whole different challenge. How can I teach the kids and their teachers about programming in a fun way?

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  • Why can't decimal numbers be represented exactly in binary?

    - by Barry Brown
    There have been several questions posted to SO about floating-point representation. For example, the decimal number 0.1 doesn't have an exact binary representation, so it's dangerous to use the == operator to compare it to another floating-point number. I understand the principles behind floating-point representation. What I don't understand is why, from a mathematical perspective, are the numbers to the right of the decimal point any more "special" that the ones to the left? For example, the number 61.0 has an exact binary representation because the integral portion of any number is always exact. But the number 6.10 is not exact. All I did was move the decimal one place and suddenly I've gone from Exactopia to Inexactville. Mathematically, there should be no intrinsic difference between the two numbers -- they're just numbers. By contrast, if I move the decimal one place in the other direction to produce the number 610, I'm still in Exactopia. I can keep going in that direction (6100, 610000000, 610000000000000) and they're still exact, exact, exact. But as soon as the decimal crosses some threshold, the numbers are no longer exact. What's going on? Edit: to clarify, I want to stay away from discussion about industry-standard representations, such as IEEE, and stick with what I believe is the mathematically "pure" way. In base 10, the positional values are: ... 1000 100 10 1 1/10 1/100 ... In binary, they would be: ... 8 4 2 1 1/2 1/4 1/8 ... There are also no arbitrary limits placed on these numbers. The positions increase indefinitely to the left and to the right.

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  • Commercial web application--scalable database design

    - by Rob Campbell
    I'm designing a set of web apps to track scientific laboratory data. Each laboratory has several members, each of whom will access both their own data and that of their laboratory as a whole. Many typical queries will thus be expected to return records of multiple members (e.g. my mouse, joe's mouse and sally's mouse). I think I have the database fairly well normalized. I'm now wondering how to ensure that users can efficiently access both their own data and their lab's data set when it is mixed among (hopefully) a whole ton of records from other labs. What I've come up with so far is that most tables will end with two fields: user_id and labgroup_id. The WHERE clause of any SELECT statement will include the appropriate reference to one of the id fields ("...WHERE 'labroup_id=n..." or "...WHERE user_id=n..."). My questions are: Is this an approach that will scale to 10^6 or more records? If so, what's the best way to use these fields in a query so that it most efficiently searches the relevant subset of the database? e.g. Should the first step in querying be to create a temporary table containing just the labgroup's data? Or will indexing using some combination of the id, user_id, and labroup_id fields be sufficient at that scale? I thank any responders very much in advance.

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  • PreparedStatement question in Java against Oracle.

    - by fardon57
    Hi everyone, I'm working on the modification of some code to use preparedStatement instead of normal Statement, for security and performance reason. Our application is currently storing information into an embedded derby database, but we are going to move soon to Oracle. I've found two things that I need your help guys about Oracle and Prepared Statement : 1- I've found this document saying that Oracle doesn't handle bind parameters into IN clauses, so we cannot supply a query like : Select pokemon from pokemonTable where capacity in (?,?,?,?) Is that true ? Is there any workaround ? ... Why ? 2- We have some fields which are of type TIMESTAMP. So with our actual Statement, the query looks like this : Select raichu from pokemonTable where evolution = TO_TIMESTAMP('2500-12-31 00:00:00.000', 'YYYY-MM-DD HH24:MI:SS.FF') What should be done for a prepared Statement ? Should I put into the array of parameters : 2500-12-31 or TO_TIMESTAMP('2500-12-31 00:00:00.000', 'YYYY-MM-DD HH24:MI:SS.FF') ? Thanks for your help, I hope my questions are clear ! Regards,

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  • Good strategy for copying a "sliding window" of data from a table?

    - by chiborg
    I have a MySQL table from a third-party application that has millions of rows and only one index - the timestamp of each entry. Now I want to do some heavy self-joins and queries on the data using fields other than the timestamp. Doing the query on the original table would bring the database to a crawl, adding indexes to the table is not an option. Additionally, I only need entries that are newer than one week. My current strategy for doing the queries efficiently is to use a separate table (aux_table) that has the necessary indexes. My questions are: Is there another way to do the queries? and if not, How do I update the data in the indexed table efficiently? So far I have found two approaches for updating aux_table: Truncate aux_table and insert the desired data from the original table. Not very efficient because all the indexes must be re-crated. Check for the biggest timestamp in aux_table and insert all entries with a greater or equal timestamp from the original table. Occasionally drop older entries. Only copying entries with greater timestamp leads to dropped entries (because of entries with same timestamp that were inserted into the original table after the last update).

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  • Android XmlSerializer limitation?

    - by Rexb
    Hi all, My task is just to get an xml string using XmlSerializer. Problem is that it seems like the serializer stops adding any new element and/or attribute to the xml document when it reaches certain length (perhaps 10,000 char?). My questions: have you experience this kind of problem? What could be possible solutions? Here is my sample test code: public void doSerialize() throws XmlPullParserException, IllegalArgumentException, IllegalStateException, IOException { StringWriter writer = new StringWriter(); XmlSerializer serializer = XmlPullParserFactory.newInstance().newSerializer(); serializer.setOutput(writer); serializer.startDocument(null, null); serializer.startTag(null, "START"); for (int i = 0; i < 20; i++) { serializer.attribute(null, "ATTR" + i, "VAL " + i); } serializer.startTag(null, "DATA"); for (int i = 0; i < 500; i++) { serializer.attribute(null, "attr" + i, "value " + i); } serializer.endTag(null, "DATA"); serializer.endTag(null, "START"); serializer.endDocument(); String xml = writer.toString(); // value: until 493rd attribute int n = xml.length(); // value: 10125 } Any help will be greatly appreciated.

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  • Opening my application when a usb device is inserted on Windows using WMI

    - by rsteckly
    Hi, I'm trying to launch an event when someone plugs in a usb device. For now, I'm content to simply print something to the console (in the finished product, it will launch an application). This code is very loosely adapted from: http://serverfault.com/questions/115496/use-wmi-to-detect-a-usb-drive-was-connected-regardless-of-whether-it-was-mounted There's two problems: 1) I need to pass the argument to Management scope dynamically because this will be installed on computers I don't use or whose name I don't know. 2) I'm getting an invalid namespace exception when I call w.Start(); Any ideas what I'm doing wrong? static ManagementEventWatcher w=null; static void Main(string[] args) { AddInstUSBHandler(); for(;;); } public static void USBRemoved(object sneder, EventArgs e) { Console.WriteLine("A USB device inserted"); } static void AddInstUSBHandler() { WqlEventQuery q; ManagementScope scope = new ManagementScope("HQ\\DEV1"); scope.Options.EnablePrivileges=true; q=new WqlEventQuery(); q.EventClassName+="_InstanceCreationEvent"; q.WithinInterval=new TimeSpan(0,0,3); q.Condition=@"TargetInstance ISA 'Win32_USBControllerdevice'"; w=new ManagementEventWatcher(scope,q); w.EventArrived+=new EventArrivedEventHandler(USBRemoved); w.Start(); }

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