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• SQL 2 INNER JOINS with 3 tables

  - by Jelmer Holtes

  I've a question about a SQL query.. I'm building a prototype webshop in ASP.NET Visual Studio. Now I'm looking for a solution to view my products. I've build a database in MS Access, it consists of multiple tables. The tables which are important for my question are: Product Productfoto Foto Below you'll see the relations between the tables For me it is important to get three datatypes: Product title, price and image. The product title, and the price are in the Product table. The images are in the Foto table. Because a product can have more than one picture, there is a N - M relation between them. So I've to split it up, I did it in the Productfoto table. So the connection between them is: product.artikelnummer -> productfoto.artikelnummer productfoto.foto_id -> foto.foto_id Then I can read the filename (in the database: foto.bestandnaam) I've created the first inner join, and tested it in Access, this works: SELECT titel, prijs, foto_id FROM Product INNER JOIN Productfoto ON product.artikelnummer = productfoto.artikelnummer But I need another INNER JOIN, how could I create that? I guess something like this (this one will give me an error) SELECT titel, prijs, bestandnaam FROM Product (( INNER JOIN Productfoto ON product.artikelnummer = productfoto.artikkelnummer ) INNER JOIN foto ON productfoto.foto_id = foto.foto_id) Can anyone help me?

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• R : remove columns from dataframe where ALL values are NA

  - by Sophomore

  hello everybody! I'm having some trouble with my huge data frame and couldn't really resolve that question myself: The dataframe has some properties as columns and each row represents one data set. I've done some sanatizing to this dataframe (e.g. get rid of datasets which are not to be included in evaluation). (Whoever might be interested: Beforehand I aggregate around 5000 single text files and put them in a tsv, some of the proerties have a sequence number like "button.pressed.1" ... ""button.pressed.n". Some of the sets excluded had really high numbers for n but got excluded, all sets left have much smaller numbers for n but the property "button.presed.50" is still there and all remaining sets have an NA in that column. Actually its a different property but the example should clarify my intention...) So the question is quite simple (for some sophisticated R pro): I need to get rid of columns where for ALL rows the value is NA. Could someone please help me out? (All I have managed to get rid of columns where at least one NA exists which dropped about half my columns)...

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• Should a Trim method generally in the Data Access Layer or with in the Domain Layer?

  - by jpierson

  I'm dealing with a database that contains data with inconsistencies such as white leading and trailing white space. In general I see a lot of developers practice defensive coding by trimming almost all strings that come from the database that may have been entered by a user at some point. In my oppinoin it is better to do such formating before data is persisted so that it is done only once and then the data can be in a consistent and reliable state. Unfortunatley this is not the case however which leads me to the next best solution, using a Trim method. If I trim all data as part of my data access layer then I don't have to concern myself with defensive trimming within the business objects of my domain layer. If I instead put the trimming responsibility in my business objects, such as with set accessors of my C# properties, I should get the same net results however the trim will be operating on all values assigned to my business objects properties not just the ones that come from the inconsistent database. I guess as a somewhat philisophical question that may determine the answer I could ask "Should the domain later be responsible for defensive/coercive formatting of data?" Would it make sense to have a set accessor for a PhoneNumber property on a business object accept a unformatted or formatted string and then attempt to format it as required or should this responsibility be pushed to the presentation and data access layers leaving the domain layer more strict in the type of data that it will accept? I think this may be the more fundamental question. Update: Below are a few links that I thought I should share about the topic of data cleansing. Information service patterns, Part 3: Data cleansing pattern LINQ to SQL - Format a string before saving? How to trim values using Linq to Sql?

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• How to share the credentials between Webform and Winform?

  - by Daniel

  Hi! Question: I want to make a login form at the Clickonce deployment webpage, and only allow the authenticated users to download the application. and I want the downloaded application to use the same credentials entered at the webpage, without prompting the users to enter the credentials again. Details: I have an application(Windows Client) which needs customized settings for different users. the application is deployed through ClickOnce. Currently, the users are given the ClickOnce webpage URL, then download the application from there. after download and running the application, the application prompts users with a login form. If their credentials are authenticated, the application loads the customized settings from the server's database according to the credentials given. The problem is, any unauthenticated users can download the application if they just know the ClickOnce deployement webpage's URL. Unauthenticated users won't be able to run the application anyways, because the application asks for credentials when started, but I want to prevent the unauthenticated users from downloading the application at all. Am I asking the wrong question maybe? Your help is much appreciated!

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• asp.net mvc ajax helper/post additional data w/o jquery.

  - by Jopache

  I would like to use the ajax helper to create ajax requests that send additional, dynamic data with the post (for example, get the last element with class = blogCommentDateTime and send the value of that last one to the controller which will return only blog comments after it). I have successfully done so with the help of jQuery Form plugin like so: $(document).ready(function () { $("#addCommentForm").submit(function () { var lastCommentDate = $(".CommentDateHidden:last").val(); var lastCommentData = { lastCommentDateTicks: lastCommentDate }; var formSubmitParams = { data: lastCommentData, success: AddCommentResponseHandler } $("#addCommentForm").ajaxSubmit(formSubmitParams); return false; }); This form was created with html.beginform() method. I am wondering if there is an easy way to do this using the ajax.beginform() helper? When I try to use the same code but replace html.beginform() with ajax.beginform(), when i try to submit the form, I am issuing 2 posts (which is understandable, one being taken care of by the helper, the other one by me with the JS above. I can't create 2 requests, so this option is out) I tried getting rid of the return false and changing ajaxSubmit() to ajaxForm() so that it would only "prepare" the form, and this leads in only one post, but it does not include the extra parameter that I defined, so this is worthless as well. I then tried keeping the ajaxForm() but calling that whenever the submit button on the form gets clicked rather than when the form gets submitted (I guess this is almost the same thing) and that results in 2 posts also. The biggest reason I am asking this question is that I have run in to some issues with the javascript above and using mvc validation provided by the mvc framework (which i will set up another question for) and would like to know this so I can dive further in to my validation issue.

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• Comparing lists in Standard ML

  - by user1050640

  I am extremely new to SML and we just got out first programming assignment for class and I need a little insight. The question is: write an ML function, called minus: int list * int list -> int list, that takes two non-decreasing integer lists and produces a non-decreasing integer list obtained by removing the elements from the first input list which are also found in the second input list. For example, minus( [1,1,1,2,2], [1,1,2,3] ) = [1,2] minus( [1,1,2,3],[1,1,1,2,2] ) = [3] Here is my attempt at answering the question. Can anyone tell me what I am doing incorrectly? I don't quite understand parsing lists. fun minus(xs,nil) = [] | minus(nil,ys) = [] | minus(x::xs,y::ys) = if x=y then minus(xs,ys) else x :: minus(x,ys); Here is a fix I just did, I think this is right now? fun minus(L1,nil) = L1 | minus(nil,L2) = [] | minus(L1,L2) = if hd(L1) > hd(L2) then minus(L1,tl(L2)) else if hd(L1) = hd(L2) then minus(tl(L1),tl(L2)) else hd(L1) :: minus(tl(L1), L2);

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• Concatenating a string and byte array in to unmanaged memory.

  - by Scott Chamberlain

  This is a followup to my last question. I now have a byte[] of values for my bitmap image. Eventually I will be passing a string to the print spooler of the format String.Format("GW{0},{1},{2},{3},", X, Y, stride, _Bitmap.Height) + my binary data; I am using the SendBytesToPrinter command from here. Here is my code so far to send it to the printer public static bool SendStringPlusByteBlockToPrinter(string szPrinterName, string szString, byte[] bytes) { IntPtr pBytes; Int32 dwCount; // How many characters are in the string? dwCount = szString.Length; // Assume that the printer is expecting ANSI text, and then convert // the string to ANSI text. pBytes = Marshal.StringToCoTaskMemAnsi(szString); pBytes = Marshal.ReAllocCoTaskMem(pBytes, szString.Length + bytes.Length); Marshal.Copy(bytes,0, SOMTHING GOES HERE,bytes.Length); // this is the problem line // Send the converted ANSI string + the concatenated bytes to the printer. SendBytesToPrinter(szPrinterName, pBytes, dwCount); Marshal.FreeCoTaskMem(pBytes); return true; } My issue is I do not know how to make my data appended on to the end of the string. Any help would be greatly appreciated, and if I am doing this totally wrong I am fine in going a entirely different way (for example somehow getting the binary data concatenated on to the string before the move to unmanaged space. P.S. As a second question, will ReAllocCoTaskMem move the data that is sitting in it before the call to the new location?

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• forward invocation, by hand vs magically?

  - by John Smith

  I have the following two class: //file FruitTree.h @interface FruitTree : NSObject { Fruit * f; Leaf * l; } @end //file FruitTree.m @implementation FruitTree //here I get the number of seeds from the object f @end //file Fruit @interface Fruit : NSObject { int seeds; } -(int) countfruitseeds; @end My question is at the point of how I request the number of seeds from f. I have two choices. Either: Since I know f I can explicitly call it, i.e. I implement the method -(int) countfruitseeds { return [f countfruitseeds]; } Or: I can just use forwardInvocation: - (NSMethodSignature *)methodSignatureForSelector:(SEL)selector { // does the delegate respond to this selector? if ([f respondsToSelector:selector]) return [f methodSignatureForSelector:selector]; else if ([l respondsToSelector:selector]) return [l methodSignatureForSelector:selector]; else return [super methodSignatureForSelector: selector]; } - (void)forwardInvocation:(NSInvocation *)invocation { [invocation invokeWithTarget:f]; } (Note this is only a toy example to ask my question. My real classes have lots of methods, which is why I am asking.) Which is the better/faster method?

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• How does C#'s DateTime.Now affect query plan caching in SQL Server?

  - by Bill Paetzke

  Given: Let's say we have a stored procedure. It reports data back to a user on a webpage. The user can set a date range. If the user sets today's date as the "end date," which includes today's data, the web app passes DateTime.Now to the sql proc. Let's say that one user runs a report--5/1/2010 to now--over and over several times. On the webpage, the user sees "5/1/2010" to "5/4/2010." But the web app passes DateTime.Now to the sql proc as the end date. So, the end date in the proc will always be different, although the user is querying a similar date range. Assume the number of records in the table and number of users are large. So any performance gains matter. Hence the importance of the question. Question: Does passing DateTime.Now as a parameter to a proc prevent SQL Server from caching the query plan? If so, then is the web app missing out on huge performance gains? Possible Solution: I thought DateTime.Today.AddDays(1) would be a possible solution. It would allow the user to get the latest data and always pass the same end date to the sql proc--"5/5/2010" in this case. Please speak to this as well. Sample proc and execution (if that helps to understand): CREATE PROCEDURE GetFooData @StartDate datetime @EndDate datetime AS SELECT * FROM Foo WHERE LogDate >= @StartDate AND LogDate < @EndDate Here's a sample execution using DateTime.Now: EXEC GetFooData '2010-05-01', '2010-05-04 15:41:27' -- passed in DateTime.Now Here's a sample execution using DateTime.Today.AddDays(1) EXEC GetFooData '2010-05-01', '2010-05-05' -- passed in DateTime.Today.AddDays(1) The same data is returned for both procs, since the current time is: 2010-05-04 15:41:27.

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• What can I read from the iPad Camera Connection Kit?

  - by HELVETICADE

  I'm building a small controller device that I'd like to partner with a computer. I've settled on using OSC out from my custom built hardware and am pretty satisfied with what I can get from WOscLib. Two goals I'd like to achieve are portability and a very ratio between battery:computing power, and this has lured me towards using iPhoneOS to accomplish my goals. I think the iPad would suit my needs perfectly, except that using wifi to broadcast OSC out from my device requires a third device and would destroy the goal of portability, whilst also introducing potential latency and stability headaches. My question is pretty simple: Can I push my OSC-out FROM my controller TO an iPad via USB and the Camera Connection Kit? If I could accomplish this, the two major goals of my project would be fulfilled very nicely. This seems like it should be a simple little question, but researching this obsessively over the past few weeks has left me more almost more uncertain than if I had done no research at all. I'd really like some more confidence before I go down this route, and it seems like it should be possible. Any insight would be very, very appreciated.

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• jquery: Writing a method

  - by Mark

  This is the same question as this: http://stackoverflow.com/questions/2890620/jquery-running-a-function-in-a-context-and-adding-to-a-variable But that question was poorly posed. Trying again, I'm trying to do something like this: I have a bunch of elements I want to grab data from, the data is in the form of classes of the element children. <div id='container'> <span class='a'></span> <span class='b'></span> <span class='c'></span> </div> <div id='container2'> <span class='1'></span> <span class='2'></span> <span class='3'></span> </div> I have a method like this: jQuery.fn.grabData = function(expr) { return this.each(function() { var self = $(this); self.find("span").each(function (){ var info = $(this).attr('class'); collection += info; }); }); }; I to run the method like this: var collection = ''; $('#container').grabData(); $('#container2').grabData(); The collection should be adding to each other so that in the end I get this console.log(collection); : abc123 But collection is undefined in the method. How can I let the method know which collection it should be adding to? Thanks.

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• Can I specify default value?

  - by atch

  Why is it that for user defined types when creating an array of objects every element of this array is initialized with default ctor but when I create built-in type this isn't the case? And second question: is it possible to specify default value to be used while initialize? Something like this (not valid): char* p = new char[size]('\0'); And another question in this topic while I'm with arrays. I suppose that when creating an array of user defined type and knowing the fact that every elem. of this array will be initialized with default value firstly why? If arrays for built in types do not initialize their elems. with their dflts why do they do it for UDT, and secondly: is there a way to switch it off/avoid/circumvent somehow? It seems like bit of a waste if I for example have created an array with size 10000 and then 10000 times dflt ctor will be invoked and I will (later on) overwrite this values anyway. I think that behaviour should be consistent, so either every type of array should be initialized or none. And I think that the behaviour for built-in arrays is more appropriate.

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• What are the arguments against the inclusion of server side scripting in JavaScript code blocks?

  - by James Wiseman

  I've been arguing for some time against embedding server-side tags in JavaScript code, but was put on the spot today by a developer who seemed unconvinced The code in question was a legacy ASP application, although this is largely unimportant as it could equally apply to ASP.NET or PHP (for example). The example in question revolved around the use of a constant that they had defined in ServerSide code. 'VB Const MY_CONST: MY_CONST = 1 If sMyVbVar = MY_CONST Then 'Do Something End If //JavaScript if (sMyJsVar === "<%= MY_CONST%>"){ //DoSomething } My standard arguments against this are: Script injection: The server-side tag could include code that can break the JavaScript code Unit testing. Harder to isolate units of code for testing Code Separation : We should keep web page technologies apart as much as possible. The reason for doing this was so that the developer did not have to define the constant in two places. They reasoned that as it was a value that they controlled, that it wasn't subject to script injection. This reduced my justification for (1) to "We're trying to keep the standards simple, and defining exception cases would confuse people" The unit testing and code separation arguments did not hold water either, as the page itself was a horrible amalgam of HTML, JavaScript, ASP.NET, CSS, XML....you name it, it was there. No code that was every going to be included in this page could possibly be unit tested. So I found myself feeling like a bit of a pedant insisting that the code was changed, given the circumstances. Are there any further arguments that might support my reasoning, or am I, in fact being a bit pedantic in this insistence?

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• Any merit to a lazy-ish juxt function?

  - by NielsK

  In answering a question about a function that maps over multiple functions with the same arguments (A: juxt), I came up with a function that basically took the same form as juxt, but used map: (defn could-be-lazy-juxt [& funs] (fn [& args] (map #(apply %1 %2) funs (repeat args)))) => ((juxt inc dec str) 1) [2 0 "1"] => ((could-be-lazy-juxt inc dec str) 1) (2 0 "1") => ((juxt * / -) 6 2) [12 3 4] => ((could-be-lazy-juxt * / -) 6 2) (12 3 4) As posted in the original question, I have little clue about the laziness or performance of it, but timing in the REPL does suggest something lazy-ish is going on. => (time (apply (juxt + -) (range 1 100))) "Elapsed time: 0.097198 msecs" [4950 -4948] => (time (apply (could-be-lazy-juxt + -) (range 1 100))) "Elapsed time: 0.074558 msecs" (4950 -4948) => (time (apply (juxt + -) (range 10000000))) "Elapsed time: 1019.317913 msecs" [49999995000000 -49999995000000] => (time (apply (could-be-lazy-juxt + -) (range 10000000))) "Elapsed time: 0.070332 msecs" (49999995000000 -49999995000000) I'm sure this function is not really that quick (the print of the outcome 'feels' about as long in both). Doing a 'take x' on the function only limits the amount of functions evaluated, which probably is limited in it's applicability, and limiting the other parameters by 'take' should be just as lazy in normal juxt. Is this juxt really lazy ? Would a lazy juxt bring anything useful to the table, for instance as a compositing step between other lazy functions ? What are the performance (mem / cpu / object count / compilation) implications ? Is that why the Clojure juxt implementation is done with a reduce and returns a vector ? Edit: Somehow things can always be done simpler in Clojure. (defn could-be-lazy-juxt [& funs] (fn [& args] (map #(apply % args) funs)))

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• Which text margin does SWT Table use when drawing text?

  - by Zordid

  I got a relatively easy question - but I cannot find anything anywhere to answer it. I use a simple SWT table widget in my application that displays only text in the cells. I got an incremental search feature and want to highlight text snippets in all cells if they match. So when typing "a", all "a"s should be highlighted. To get this, I add an SWT.EraseItem listener to interfere with the background drawing. If the current cell's text contains the search string, I find the positions and calculate relative x-coordinates within the text using event.gc.stringExtent - easy. With that I just draw rectangles "behind" the occurrences. Now, there's a flaw in this. The table does not draw the text without a margin, so my x coordinate does not really match - it is slightly off by a few pixels! But how many?? Where do I retrieve the cell's text margins that table's own drawing will use? No clue. Cannot find anything. :-( Bonus question: the table's draw method also shortens text and adds "..." if it does not fit into the cell. Hmm. My occurrence finder takes the TableItem's text and thus also tries to mark occurrences that are actually not visible because they are consumed by the "...". How do I get the shortened text and not the "real" text within the EraseItem draw handler? Thanks!

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• How To Create a Flexible Plug-In Architecture?

  - by justkt

  A repeating theme in my development work has been the use of or creation of an in-house plug-in architecture. I've seen it approached many ways - configuration files (XML, .conf, and so on), inheritance frameworks, database information, libraries, and others. In my experience: A database isn't a great place to store your configuration information, especially co-mingled with data Attempting this with an inheritance hierarchy requires knowledge about the plug-ins to be coded in, meaning the plug-in architecture isn't all that dynamic Configuration files work well for providing simple information, but can't handle more complex behaviors Libraries seem to work well, but the one-way dependencies have to be carefully created. As I seek to learn from the various architectures I've worked with, I'm also looking to the community for suggestions. How have you implemented a solid plug-in architecture? What was your worst failure (or the worst failure you've seen)? What would you do if you were going to implement a new plug-in architecture? What SDK or open source project that you've worked with has the best example of a good architecture? A few examples I've been finding on my own: Perl's Module::Plugable An SO question with a list for Java (including Sever Provider Interfaces) An SO question for C++ pointing to a Dr. Dobbs article These examples seem to play to various language strengths. Is a good plugin architecture necessarily tied to the language? Is it best to use tools to create a plugin architecture, or to do it on one's own following models?

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• VirtualBox limits size of .js file, that can be included from guest additions folder?

  - by c69

  This question might belong to SuperUser, but i'll try to ask it here anyway, because i believe, some web developers might encountered this weird behavior. When testing a site for IE8/winXP compatibility on VirtualBox i run into weird issue of $ is undefined, which is caused by jQuery (and jQuery UI) being not included, when referenced by relative path, which resolves to file:/// url. Seemingly because their size was too big (above 200KB). Simply replacing links to those 2 big files to http:// ones solved the issue for me. But here is the question: why did this happen ? is it a misconfiguration ? a bug ? a known design decision ? Details: VirtualBox 4.1.8 host os: win7 64bit, guest os: xp sp3 32 bit guest additions installed, page was launched from VB shared folder the bug was manifesting itself in all browsers (even in opera, which ignores ie security settings, afaik) ie configuration is default script was included like this: <script type="text/javascript" src="js/libs/jquery/jquery-1.7.2.js"> exact size limit was not deducted.

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• Broken console in Maven project using Netbeans

  - by Maciek Sawicki

  Hi, I have strange problem with my Neatens+Maven installation. This is the shortest code to reproduce the problem: public class App { public static void main( String[] args ) { // Create a scanner to read from keyboard Scanner scanner = new Scanner (System.in); Scanner s= new Scanner(System.in); String param= s.next(); System.out.println(param); } } When I'm running it as Maven Project inside Netbeans console seems to be broken. It just ignores my input. It's look like infinitive loop in System.out.println(param);. However this project works fine when it's compiled as "Java Aplication" project. It also works O.K. if I build and run it from cmd. System info: Os: Vista IDE: Netbeans 6.8 Maven: apache-maven-2.2.1 //edit Built program (using mavean from Netbeans) works fine. I just can't test it using Net beans. And I think I forgot to ask the question ;). So of course my first question is: how can I fix this problem? And second is: Is it any workaround for this? For example configuring Netbeans to run external commend line app instead of using built in console.

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• How to create more complex Lucene query strings?

  - by boris callens

  This question is a spin-off from this question. My inquiry is two-fold, but because both are related I think it is a good idea to put them together. How to programmatically create queries. I know I could start creating strings and get that string parsed with the query parser. But as I gather bits and pieces of information from other resources, there is a programattical way to do this. What are the syntax rules for the Lucene queries? --EDIT-- I'll give a requirement example for a query I would like to make: Say I have 5 fields: First Name Last Name Age Address Everything All fields are optional, the last field should search over all the other fields. I go over every field and see if it's IsNullOrEmpty(). If it's not, I would like to append a part of my query so it adds the relevant search part. First name and last name should be exact matches and have more weight then the other fields. Age is a string and should exact match. Address can varry in order. Everything can also varry in order. How should I go about this?

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• Given a main function and a cleanup function, how (canonically) do I return an exit status in Bash/Linux?

  - by Zac B

  Context: I have a bash script (a wrapper for other scripts, really), that does the following pseudocode: do a main function if the main function returns: $returncode = $? #most recent return code if the main function runs longer than a timeout: kill the main function $returncode = 140 #the semi-canonical "exceeded allowed wall clock time" status run a cleanup function if the cleanup function returns an error: #nonzero return code exit $? #exit the program with the status returned from the cleanup function else #cleanup was successful .... Question: What should happen after the last line? If the cleanup function was successful, but the main function was not, should my program return 0 (for the successful cleanup), or $returncode, which contains the (possibly nonzero and unsuccessful) return code of the main function? For a specific application, the answer would be easy: "it depends on what you need the script for." However, this is more of a general/canonical question (and if this is the wrong place for it, kill it with fire): in Bash (or Linux in general) programming, do you typically want to return the status that "means" something (i.e. $returncode) or do you ignore such subjectivities and simply return the code of the most recent function? This isn't Bash-specific: if I have a standalone executable of any kind, how, canonically should it behave in these cases? Obviously, this is somewhat debatable. Even if there is a system for these things, I'm sure that a lot of people ignore it. All the same, I'd like to know. Cheers!

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• using a 64-bit compiler in microsoft visual c++

  - by Ben

  this question is essentially identical to an earlier question i had that didn't receive any answers. hopefully someone can help me out this time. i am trying to compile a vc++ project as 64 bit using visual c++ express 2010. i know that the 64 bit compiler does not come with the default installation of vc++ express so i installed windows sdk for windows 7 as specified here (http://msdn.microsoft.com/en-us/library/9yb4317s.aspx) which includes the 64 bit compiler as i understand. however, there is still no 64 bit option in the configuration manager for vc++. after some searching i found and completed this tutorial (http://jenshuebel.wordpress.com/2009/02/12/visual-c-2008-express-edition-and-64-bit-targets/) as well as the various links at the bottom of this page. despite all my efforts, i still cannot get the 64 bit compiler to show in vc++ (i.e. the 64 bit compiler won't show under "active solutions platform" in the configuration manager). if anyone has any experience/tips with getting this to work i would really appreciate it. fyi - i am running windows 7(x64).

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• stackoverflow tags and related tags

  - by parminder

  Hi Experts, I am working on a website where a user can add tags to their posted books. It is similar to stackover flow, but I am keeping my tags in differnt table. so here are the tables/class in linq to entities. Books { bookId, Title } Tags { Id Tag } BooksTags { Id BookId TagId } Here are few sample records. Books BookId Title 113421 A 113422 B Tags Id Tag 1 ASP 2 C# 3 CSS 4 VB 5 VB.NET 6 PHP 7 java 8 pascal BooksTags Id BookId TagId 1 113421 1 2 113421 2 3 113421 3 4 113421 4 5 113422 1 6 113422 4 7 113422 8 Question 1 : I need to write something in linq to entities queries which gives me data according to the tags say if I want bookIds where tagid =1 it should return bookid 113421 and 113422 as it exists in both the books, but If I ask data for tags 1 and 2 it should return only book 113421 as that is the only book where both the tags are present. Question 2 : I need tags and their count too to show in related tags, so in first case my related tags class should have following result. RelatedTags Tag Count 2 1 3 1 4 2 8 1 in the second case when two tags are requested the result should be like RelatedTags Tag Count 3 1 4 1 I have get the first thing working by converting a sql query in linqer, but that seems like a hell. so want to know if there is any better idea. I have used dyanmic where clause to include two tags. So if someone can help. It will be much appreciated. Thanks Parminder

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• Pros and Cons of using SqlCommand Prepare in C#?

  - by MadBoy

  When i was reading books to learn C# (might be some old Visual Studio 2005 books) I've encountered advice to always use SqlCommand.Prepare everytime I execute SQL call (whether its' a SELECT/UPDATE or INSERT on SQL SERVER 2005/2008) and I pass parameters to it. But is it really so? Should it be done every time? Or just sometimes? Does it matter whether it's one parameter being passed or five or twenty? What boost should it give if any? Would it be noticeable at all (I've been using SqlCommand.Prepare here and skipped it there and never had any problems or noticeable differences). For the sake of the question this is my usual code that I use, but this is more of a general question. public static decimal pobierzBenchmarkKolejny(string varPortfelID, DateTime data, decimal varBenchmarkPoprzedni, decimal varStopaOdniesienia) { const string preparedCommand = @"SELECT [dbo].[ufn_BenchmarkKolejny](@varPortfelID, @data, @varBenchmarkPoprzedni, @varStopaOdniesienia) AS 'Benchmark'"; using (var varConnection = Locale.sqlConnectOneTime(Locale.sqlDataConnectionDetailsDZP)) //if (varConnection != null) { using (var sqlQuery = new SqlCommand(preparedCommand, varConnection)) { sqlQuery.Prepare(); sqlQuery.Parameters.AddWithValue("@varPortfelID", varPortfelID); sqlQuery.Parameters.AddWithValue("@varStopaOdniesienia", varStopaOdniesienia); sqlQuery.Parameters.AddWithValue("@data", data); sqlQuery.Parameters.AddWithValue("@varBenchmarkPoprzedni", varBenchmarkPoprzedni); using (var sqlQueryResult = sqlQuery.ExecuteReader()) if (sqlQueryResult != null) { while (sqlQueryResult.Read()) { //sqlQueryResult["Benchmark"]; } } } }

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• Time complexity to fill hash table (homework)?

  - by Heathcliff

  This is a homework question, but I think there's something missing from it. It asks: Provide a sequence of m keys to fill a hash table implemented with linear probing, such that the time to fill it is minimum. And then Provide another sequence of m keys, but such that the time fill it is maximum. Repeat these two questions if the hash table implements quadratic probing I can only assume that the hash table has size m, both because it's the only number given and because we have been using that letter to address a hash table size before when describing the load factor. But I can't think of any sequence to do the first without knowing the hash function that hashes the sequence into the table. If it is a bad hash function, such that, for instance, it hashes every entry to the same index, then both the minimum and maximum time to fill it will take O(n) time, regardless of what the sequence looks like. And in the average case, where I assume the hash function is OK, how am I suppossed to know how long it will take for that hash function to fill the table? Aren't these questions linked to the hash function stronger than they are to the sequence that is hashed? As for the second question, I can assume that, regardless of the hash function, a sequence of size m with the same key repeated m-times will provide the maximum time, because it will cause linear probing from the second entry on. I think that will take O(n) time. Is that correct? Thanks

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• How are you using C++0x today? [closed]

  - by Roger Pate

  This is a question in two parts, the first is the most important and concerns now: Are you following the design and evolution of C++0x? What blogs, newsgroups, committee papers, and other resources do you follow? Even where you're not using any new features, how have they affected your current choices? What new features are you using now, either in production or otherwise? The second part is a follow-up, concerning the new standard once it is final: Do you expect to use it immediately? What are you doing to prepare for C++0x, other than as listed for the previous questions? Obviously, compiler support must be there, but there's still co-workers, ancillary tools, and other factors to consider. What will most affect your adoption? Edit: The original really was too argumentative; however, I'm still interested in the underlying question, so I've tried to clean it up and hopefully make it acceptable. This seems a much better avenue than duplicating—even though some answers responded to the argumentative tone, they still apply to the extent that they addressed the questions, and all answers are community property to be cleaned up as appropriate, too.

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