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• Help with complex sql query

  - by eugeneK

  To make story short, i'm building self-learning banner management system. Users will be able to insert these banners to their site when banners will be shown based on sales/impressions ratio. I have 4 tables Banners bannerID int bannerImage varchar.... SmartBanners smartBannerID int smartBannerArrayID int bannerID int impressionsCount int visibility tinyint (percents) SmartBannerArrays smartBannerArrayID int userID int Statistics bannerID int saleAmountPerDay decimal... Each night i need to generate new "visibility" for each SmartBanner based on whole SmartBannerArray that same user has. So i need to get sum of impressions and sales for each bannerID in SmartBannerArray. All comes to my mind is to use double cursor, one will loop thought SmartBannerArrays get needed values for sum of impressions and sales and then inner loop which will access each SmartBanner and change it's "visibility" percentage based on (sales/impressions)/(sumOfSales/sumOfImpressions)*100 Hope you get the picture... Is there any other way to design better tables or not to use double cursor to avoid server overload ?

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• Full Width Divs using ScrollTo.js

  - by David Haigh

  This is my first ever post. I am using the ScrollTo jQuery plugin and i have stumbled across a problem... I have 6 rows, each with 6 child divs , I would like each of these child divs to be full width. The plugin works great but I cannot seem to get the child div to be full width (then use ScrollTo to 'slide' to the next div, or to a div on the next row. ) Here is my code: http://jsfiddle.net/RZjrV/ Is it even possible? I have set body - Overflow:hidden to avoid any initial confusion. Thank you all who read this post and even take a minute to think about it. David

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• When is JavaScript's eval() not evil?

  - by Richard Turner

  I'm writing some JavaScript to parse user-entered functions (for spreadsheet-like functionality). Having parsed the formula I could convert it into JavaScript and run eval() on it to yield the result. However, I've always shied away from using eval() if I can avoid it because it's evil (and, rightly or wrongly, I've always thought it is even more evil in JavaScript because the code to be evaluated might be changed by the user). Obviously one has to use eval() to parse JSON (I presume that JS libraries use eval() for this somewhere, even if they run the JSON through a regex check first), but when else, other than when manipulating JSON, it is OK to use eval()?

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• Unable to make 2 parallel TCP requests to the same TCP Client

  - by soldieraman

  Error: Unable to read data from the transport connection: A blocking operation was interrupted by a call to WSACancelBlockingCall Situation There is a TCP Server My web application connects to this TCP Server Using the below code: TcpClientInfo = new TcpClient(); _result = TcpClientInfo.BeginConnect(<serverAddress>,<portNumber>, null, null); bool success = _result.AsyncWaitHandle.WaitOne(20000, true); if (!success) { TcpClientInfo.Close(); throw new Exception("Connection Timeout: Failed to establish connection."); } NetworkStreamInfo = TcpClientInfo.GetStream(); NetworkStreamInfo.ReadTimeout = 20000; 2 Users use the same application from two different location to access information from this server at the SAME TIME Server takes around 2sec to reply Both Connect But One of the user gets above error "Unable to read data from the transport connection: A blocking operation was interrupted by a call to WSACancelBlockingCall" when trying to read data from stream How can I resolve this issue? Use a better way of connecting to the server Can't because it's a server issue if a server issue, how should the server handle request to avoid this problem

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• It's possible to don't pass in GET some fields of a form?

  - by avastreg

  I have a form with some input texts passed in GET, and i don't want to have in GET all the fields; i want to avoid empty fields. So, a concrete example for: <form method="GET" action="an_url"> <input type="text" name="field1"/> <input type="text" name="field2"/> <input type="text" name="field3"/> <input type="submit" value="submit"/> </form> I supposed that fields disabled by html attribute "disabled" shouldn't be passed to GET. So i have done a js (based on jquery) to disable empty fields on submit, something like this: $("form").submit(function() { $(this).find("input[type=text]").each( function () { if (!$.trim($(this).val())) { $(this).attr("disabled", "true"); } }); }); However, this doesn't work. Any ideas?

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• Optimize code performance when odd/even threads are doing different things in CUDA

  - by Orion Nebula

  Hi all! I have two large vectors, I am trying to do some sort of element multiplication, where an even-numbered element in the first vector is multiplied by the next odd-numbered element in the second vector .... and where the odd-numbered element in the first vector is multiplied by the preceding even-numbered element in the second vector Ex. vector 1 is V1(1) V1(2) V1(3) V1(4) vector 2 is V2(1) V2(2) V2(3) V2(4) V1(1) * V2(2) V1(3) * V2(4) V1(2) * V2(1) V1(4) * V2(3) I have written a Cuda code to do this: (Pds has the elements of the first vector in shared memory, Nds the second Vector) //instead of using %2 .. i check for the first bit to decide if number is odd/even -- faster if ((tx & 0x0001) == 0x0000) Nds[tx+1] = Pds[tx] * Nds[tx+1]; else Nds[tx-1] = Pds[tx] * Nds[tx-1]; __syncthreads(); Is there anyway to further accelerate this code or avoid divergence ? Thanks

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• Windows 32 or 64 bit using HKEY_LOCAL_MACHINE\Software\WOW6432 Node

  - by JimDel

  I'm looking for a very simple way of determining if the version of Windows the customer is using is 32bit or 64bit. I know there are ways using .NEt but I'm looking to avoid them. I simply want to use something similar the below pseudo code and want to know if this method can be reliable. If Registry Key exists (HKEY_LOCAL_MACHINE\Software\WOW6432Node) Then Assume 64bit else Assume 32bit Thanks! EDIT: To be more specific, I know there a several different ways to accomplish the goal of finding out if the OS is 32 or 64bit. But I want to know if the above alone method would be reliable.

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• Automatically deleting pyc files when corresponding py is moved (Mercurial)

  - by Oddthinking

  (I foresaw this problem might happen 3 months ago, and was told to be diligent to avoid it. Yesterday, I was bitten by it, hard, and now that it has cost me real money, I am keen to fix it.) If I move one of my Python source files into another directory, I need to remember to tell Mercurial that it moved (hg move). When I deploy the new software to my server with Mercurial, it carefully deletes the old Python file and creates it in the new directory. However, Mercurial is unaware of the pyc file in the same directory, and leaves it behind. The old pyc is used preferentially over new python file by other modules in the same directory. What ensues is NOT hilarity. How can I persuade Mercurial to automatically delete my old pyc file when I move the python file? Is there another better practice? Trying to remember to delete the pyc file from all the Mercurial repositories isn't working.

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• jquery checked checkbox IE problem

  - by lidermin

  Hi, I'm having an issue verifying if a checkbox is checked using jquery on Internet Explorer. This is the code I'm using: if ($('#chkjq_1').attr('checked') == true) It works fine on Firefox or Chrome, but on Internet Explorer 7, the condition is always false because the browser sets the property this way: <input id="chkjq_1" type="checkbox" CHECKED/> IE7 And the right way is the following: (Firefox, Chrome): <input id="chkjq_1" type="checkbox" checked="checked"/> FF, Chrome, etc What should I do to avoid this issue on Internet Explorer 7; is there a generic way in jquery to solve this? Thanks in advance.

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• ObjectDisposedException when outputting to console

  - by Sarah Vessels

  If I have the following code, I have no runtime or compilation problems: if (ConsoleAppBase.NORMAL_EXIT_CODE == code) { StdOut.WriteLine(msg); } else { StdErr.WriteLine(msg); } However, in trying to make this more concise, I switched to the following code: (ConsoleAppBase.NORMAL_EXIT_CODE == code ? StdOut : StdErr ).WriteLine(msg); When I have this code, I get the following exception at runtime: System.ObjectDisposedException: Cannot write to a closed TextWriter Can you explain why this happens? Can I avoid it and have more concise code like I wanted?

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• Development deployment: how to achive edit-and-reload with JSP pages?

  - by doublep

  Out project uses WebLogic as web-server and uses mostly JSP for user interface. With standard setup it is possible to copy edited JSP files into the exploded deployment directory and WebLogic will automatically pick them up, recompile and serve new content through HTTP. However, is it possible to avoid copying at all, so that I just save a file in my editor and it is immediately (well, after a couple of seconds for recompilation) visible? The project uses Apache Ant as building tool. I would imagine what I want would be possible with symlinks (since this is for deployment only I don't care about cross-platformity), but then I don't see how it is possible to symlink lots of files at once with Ant. So, how do I achieve save-JSP-hit-F5-in-browser functionality either with some setting in WebLogic; or with symlinking JSPs using Apache Ant (instead of copying them as is done now); or something else completely?

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• Model Binding an IList of selected items only

  - by jeef3

  I have an action method setup: public ActionResult Delete(IList<Product> products) And a table of products in my view. I have got Model Binding working so that on submit I can populate the products list. But I would like to populate it with only the products that are selected via a checkbox. I think I could do it by changing the action method to this: public ActionResult Delete(IList<Product> products, IList<int> toDelete) And passing the list of check boxes to the toDelete but I would really like to avoid changing the method signature if possible. Is there a way to pass only the selected items? Or am I going to have to write a custom ModelBinder?

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• Adding pdb files to VSS

  - by George

  Every time I try to compile my web app, I am prompted if i want to add pdb extensioned files to VSS. I thought pdb files do not belong in VSS see a previous post. Is there any way to prevent them from being added. I cannot even logically delete them from VSS because a previous version has been logically deleted and if I were to delete the current version, the previous version would have to be purged, for which I need vss admin rights that I do not have. I just can't get a handle on how to avoid getting a million files added to VSS that prevent otehr develoeprs from compiling their solutions because they have unchecked out read only copies. Is the only solution to check them in but flip the readonly flag off locally? This is not a good option in my mind.

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• Lazy loading in Hibernate

  - by Steve

  My Java Web application uses Hibernate to perform ORM. In some of my objects, I use lazy loading to avoid getting data until I absolutely need it. The problem is that I load the initial object in a session, and then that session is destroyed. When I later attempt to resolve the lazy-loaded collections in my object I get the following error: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: common.model.impl.User.groups, no session or session was closed I tried associating a new session with the collection and then resolving, but this gives the same results. Does anyone know how I can resolve the lazy collections once the original session is gone? Thanks... --Steve

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• Converting from SQL Server 2000 to 2005 for ASP.NET web App

  - by Bazza Formez

  Hi there, I'm moving my ASP.NET website to a new provider. Only problem is, old host support my SQL Server 2000 db. New host only supports SQL Server 2005. How should I go about the conversion ? Can I simply produce a backup of the 2000 (.bak) file at the old host, and restore that file into SQL Server 2005 at the new host ? Or is there more to it ?? Note that I don't own a copy of SQL Server 2005 at home... and I'm trying to avoid having to do so. Thanks, Bazza

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• Saving gzipped string into Sqlite3 via Rails throws unrecognized token error

  - by user141146

  Hi, I'm using rails 2.3 and I'm trying to compress (gzip) text that I'd like to save using ActiveRecord into a sqlite database. However, the compressed text isn't being saved b/c I get this type of error: SQLite3::SQLException: unrecognized token: "'x##U?#7 Any thoughts on what I can do to avoid this error? should I compress the text in some other fashion? should I save the data using some other method(s)? Relevant code is below. # compress my text require 'zlib' defl = Zlib::Deflate test_string = "<h3>some text</h3>some additional text<p>here's some more text</p>" compressed_string = defl.deflate(test_string) => "x\234\263\3110\266+\316\317MU(I\255(\261\321\207\361\022SR2K2\363\363\022s \022\005v\031\251E\251\352\305\n`\331\334\374\"\230\206\002;\000\0225\027\222" ModelClass.new(:attribute1 => compressed_string).save ActiveRecord::StatementInvalid: SQLite3::SQLException: unrecognized token: "'x#####+##MU(I#(#?####2K2#### v#E####

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• explicit copy constructor or implicit parameter by value

  - by R Samuel Klatchko

  I recently read (and unfortunately forgot where), that the best way to write operator= is like this: foo &operator=(foo other) { swap(*this, other); return *this; } instead of this: foo &operator=(const foo &other) { foo copy(other); swap(*this, copy); return *this; } The idea is that if operator= is called with an rvalue, the first version can optimize away construction of a copy. So when called with a rvalue, the first version is faster and when called with an lvalue the two are equivalent. I'm curious as to what other people think about this? Would people avoid the first version because of lack of explicitness? Am I correct that the first version can be better and can never be worse?

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• Possible apache/mysql/php wrapper?

  - by MrStatic

  I was tasked with writing a smallish program for data input and manipulation. My language of choice happens to be PHP. I have written out the program/site it all works fine is easily portable and everything but have one question. Is there anyway to wrap up apache/mysql/php into a bundle of one exe? I know of MoWes Portable and other options but I am looking to basically wrap everything up into a single exe without much fuss to the end user. My target users are very low on the computer savvy scale. I am trying to avoid a batch file for launching and don't really want them able to shutdown one part on accident and not another (IE shut off mysql but leave apache on).

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• Correct way to detect sequence parameter?

  - by noamtm

  I want to write a function that accepts a parameter which can be either a sequence or a single value. The type of value is str, int, etc., but I don't want it to be restricted to a hardcoded list. In other words, I want to know if the parameter X is a sequence or something I have to convert to a sequence to avoid special-casing later. I could do type(X) in (list, tuple) but there may be other sequence types I'm not aware of, and no common base class. -N. Edit: See my "answer" below for why most of these answers don't help me. Maybe you have something better to suggest.

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• Static Access To Multiple Instance Variable

  - by Qua

  I have a singleton instance that is referenced throughout the project which works like a charm. It saves me the trouble from having to pass around an instance of the object to every little class in the project. However, now I need to manage multiple instances of the previous setup, which means that the singleton pattern breaks since each instance would need it's own singleton instance. What options are there to still maintain static access to the singleton? To be more specific, we have our game engine and several components and plugins reference the engine through a static property. Now our server needs to host multiple game instances each having their own engine, which means that on the server side the singleton pattern breaks. I'm trying to avoid all the classes having the engine in the constructor.

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• Does DB2 have an "insert or update" statement?

  - by Mikael Eriksson

  From my code (Java) I want to ensure that a row exists in the database (DB2) after my code is executed. My code now does a select and if no result is returned it does an insert. I really don't like this code since it exposes me to concurrency issuses when running in a multi-threaded environment. What I would like to do is to put this logic in DB2 instead of in my Java code. Does DB2 have an "insert-or-update" statement? Or anything like it that I can use? For example: insertupdate into mytable values ('myid') Another way of doing it would probably be to allways do the insert and catch "SQL-code -803 primary key already exists", but I would like to avoid that if possible.

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• Showing Live Wallpaper in a 1.6 target app by detecting if it's a 2.1 device?

  - by itamarw

  We're building an Android app with target SDK 1.6, so it will run on 1.6 devices and higher. We'd like to support Live Wallpapers, which we know is 2.1+ only. Is there a way to build one app with 1.6 SDK as the target, but detect if the device it's running on is 2.1, and only in that scenario call the live wallpaper API. We're trying to avoid having to build a separate 1.6 and 2.1 versions, and would like to be able to support Live Wallpapers for only 2.1 devices. So to be clear- 1 app, that can support 1.6 and higher, and support live wallpapers for 2.1 devices. Any way of doing this?

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• Communication between Page and User Controls

  - by Narmatha Balasundaram

  I have a main page that has multiple user controls on it. All the user controls have static text and some data to be retrieved from the DB. The aysnchronous DB call is clubbed at the page level and one call is made to avoid multiple calls (in the different user controls) to get the same data. I want the page and user controls to load initially with the static text and later refresh the contents obtained from the server. To sum it all up, Page Loads = Asyn calls fired on page load = Data received back from the server (XML/text/whatever) = User controls to load with this data using AJAX. What methods do I have to let the user controls know that I have the data from the server and they need to update with this data?

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• Explanation for expires header

  - by sushil bharwani

  I have a joomla application working on Apache.To improve site performace we have written a .htaccess file to root of the application with setting a far future expires header to all the static content. As desired first time the files load in fresh with 200 status code. when again click on the same link many of the files are served directly from cache. I need explanation for two things When i press f5 then a number of files load with 304 status code however i expected them to be coming directly from cache without hitting the server for a status header? When i close the browser and come back to the same page again i see the same thing happening a number of files load with 304 status code although i thought they will load directly from the browser cache? I understand that 304 also servs file from browser cache but i want to avoid the header communication between servers as my static files wont ever change. Also i want to add that my requests are over a https connection does that create any issue.

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• Opposite of Bloom filter?

  - by abc

  Hi, I'm trying to optimize a piece of software which is basically running millions of tests. These tests are generated in such a way that there can be some repetitions. Of course, I don't want to spend time running tests which I already ran if I can avoid it efficiently. So, I'm thinking about using a Bloom filter to store the tests which have been already ran. However, the Bloom filter errs on the unsafe side for me. It gives false positives. That is, it may report that I've ran a test which I haven't. Although this could be acceptable in the scenario I'm working on, I was wondering if there's an equivalent to a Bloom filter, but erring on the opposite side, that is, only giving false negatives. I've skimmed through the literature without any luck.

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