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  • Having to insert a record, then update the same record warrants 1:1 relationship design?

    - by dianovich
    Let's say an Order has many Line items and we're storing the total cost of an order (based on the sum of prices on order lines) in the orders table. -------------- orders -------------- id ref total_cost -------------- -------------- lines -------------- id order_id price -------------- In a simple application, the order and line are created during the same step of the checkout process. So this means INSERT INTO orders .... -- Get ID of inserted order record INSERT into lines VALUES(null, order_id, ...), ... where we get the order ID after creating the order record. The problem I'm having is trying to figure out the best way to store the total cost of an order. I don't want to have to create an order create lines on an order calculate cost on order based on lines then update record created in 1. in orders table This would mean a nullable total_cost field on orders for starters... My solution thus far is to have an order_totals table with a 1:1 relationship to the orders table. But I think it's redundant. Ideally, since everything required to calculate total costs (lines on an order) is in the database, I would work out the value every time I need it, but this is very expensive. What are your thoughts?

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  • Can't authenticate mobile client with node.js (using passport.js)

    - by Pazinio
    I'm trying to build some CRUD application with node.js as a back-end API (express) and web-app (backbone) and mobile client (native android) as front-ends.(I'm node.js beginner) My server solution is based on the following great tutorial 'easy-node-authentication'. In my android app I have managed to get the user Google-Token after I completed the authentication step with Google Plus SDK.(mobile to google-plus directly request). I'm trying to understand and find right and elegant way to re-use a given google-token and authenticate again my android user through Google-Plus account to ensure the mobile client holds real token, then add a new entry (id, token, email, name) to my users table DB within my node back-end. The question is: what should be my next step in case I want to keep my back-end without changes? should I send a GET request with the token as a cookie to /auth/google? maybe to /auth/google/callback? another URL? Does this make sense at all? Please note: I'm aware to the fact the mentioned above 'easy-node-auth' solution is based on sessions and cookies. having said that, i'm still trying to understand if there is a convenient way to integrate both (android and node) as it works good for my web-app and node. Thanks in advance.

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  • First Time Architecturing?

    - by cam
    I was recently given the task of rebuilding an existing RIA. The new RIA that I've designed is based on Silverlight, with a WCF service to connect to MS SQL Server. This is my first time doing something like this, so I'm not sure how to design the entire thing. Basically, the client can look through graphs of "stocks" (allowing the client to choose different time periods, settings, etc). I've written the whole application essentially, but I'm not sure how to put it together. The graphs are supposed to be directly based on the database, and to create the datapoints on the graph, some calculations need to be done (not very expensive ones). The problem I'm having is to decide where to put the calculations (client or serverside? Or half and half?) What factors should I look for to help me decide where the calculations should be done? And how can I go about optimizing this (caching, etc)? Obviously this is a very broad subject, so I'm not expecting an immediate answer, but any help/pointing in the right direction/resources would be appreciated.

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  • How string accepting interface should look like?

    - by ybungalobill
    Hello, This is a follow up of this question. Suppose I write a C++ interface that accepts or returns a const string. I can use a const char* zero-terminated string: void f(const char* str); // (1) The other way would be to use an std::string: void f(const string& str); // (2) It's also possible to write an overload and accept both: void f(const char* str); // (3) void f(const string& str); Or even a template in conjunction with boost string algorithms: template<class Range> void f(const Range& str); // (4) My thoughts are: (1) is not C++ish and may be less efficient when subsequent operations may need to know the string length. (2) is bad because now f("long very long C string"); invokes a construction of std::string which involves a heap allocation. If f uses that string just to pass it to some low-level interface that expects a C-string (like fopen) then it is just a waste of resources. (3) causes code duplication. Although one f can call the other depending on what is the most efficient implementation. However we can't overload based on return type, like in case of std::exception::what() that returns a const char*. (4) doesn't work with separate compilation and may cause even larger code bloat. Choosing between (1) and (2) based on what's needed by the implementation is, well, leaking an implementation detail to the interface. The question is: what is the preffered way? Is there any single guideline I can follow? What's your experience?

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  • Radio buttons change variable in JavaScript

    - by dmanexe
    I have two fields which calculate a total, but I have a radio button pair that determines a variable within the equation. Here's the radio button code: <input type="radio" name="estimate_pool_shape" value="1" /> Angle <input type="radio" name="estimate_pool_shape" value=".86392" /> Freeform Immediately after that, this JavaScript is then calculating the surface area of the pool based of these fields and script: (Length <input type="text" size="5" name="estimate_pool_length" onBlur="conv2inches(document.forms.mainform);" />) x (Width <input type="text" name="estimate_pool_width" size="5" onBlur="conv2inches(document.forms.mainform);" />) The following JavaScript already works to update the fields, I just need the variable it uses to set the field values to change based on the radio buttons. function conv2inches(mainform) { var oin; var oinches; if(isNaN(mainform.estimate_pool_width.value)||isNaN(mainform.estimate_pool_length.value)){ alert("Please enter numbers only"); return false; } oin = ((mainform.estimate_pool_width.value) + (mainform.estimate_pool_length.value) * %%%RADIO BUTTON VARIABLE HERE%%%); oinches = (oin); if(oinches==0){ alert("Please enter valid values into the boxes"); } mainform.estimate_pool_sqft.value = oinches; return false; }

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  • Find out how much storage a row is taking up in the database

    - by Vaccano
    Is there a way to find out how much space (on disk) a row in my database takes up? I would love to see it for SQL Server CE, but failing that SQL Server 2008 works (I am storing about the same data in both). The reason I ask is that I have a Image column in my SQL Server CE db (it is a varbinary[max] in the SQL 2008 db) and I need to know now many rows I can store before I max out the memory on my device.

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  • How to limit TCP writes to particular size and then block untlil the data is read

    - by ustulation
    {Qt 4.7.0 , VS 2010} I have a Server written in Qt and a 3rd party client executable. Qt based server uses QTcpServer and QTcpSocket facilities (non-blocking). Going through the articles on TCP I understand the following: the original implementation of TCP mentioned the negotiable window size to be a 16-bit value, thus maximum being 65535 bytes. But implementations often used the RFC window-scale-extension that allows the sliding window size to be scalable by bit-shifting to yield a maximum of 1 gigabyte. This is implementation defined. This could have resulted in majorly different window sizes on receiver and sender end as the server uses Qt facilities without hardcoding any window size limit. Client 1st asks for all information it can based on the previous messages from the server before handling the new (accumulating) incoming messages. So at some point Server receives a lot of messages each asking for data of several MB's. This the server processes and puts it into the sender buffer. Client however is unable to handle the messages at the same pace and it seems that client’s receiver buffer is far smaller (65535 bytes maybe) than sender’s transmit window size. The messages thus get accumulated at sender’s end until the sender’s buffer is full too after which the TCP writes on sender would block. This however does not happen as sender buffer is much larger. Hence this manifests as increase in memory consumption on the sender’s end. To prevent this from happening, I used Qt’s socket’s waitForBytesWritten() with timeout set to -1 for infinite waiting period. This as I see from the behaviour blocks the thread writing TCP data until the data has actually been sensed by the receiver’s window (which will happen when earlier messages have been processed by the client at application level). This has caused memory consumption at Server end to be almost negligible. is there a better alternative to this (in Qt) if i want to restrict the memory consumption at server end to say x MB's? Also please point out if any of my understandings is incorrect.

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  • How to sort data in a table data structure in Java?

    - by rgksugan
    I need to sort data based on the third column of the table data structure. I tried based on the answers for the following question. But my sorting does not work. Please help me in this. Here goes my code. Object[] data = new Object[y]; rst.beforeFirst(); while (rst.next()) { int p_id = Integer.parseInt(rst.getString(1)); String sw2 = "select sum(quantity) from tbl_order_detail where product_id=" + p_id; rst1 = stmt1.executeQuery(sw2); rst1.next(); String sw3 = "select max(order_date) from tbl_order where tbl_order.`Order_ID` in (select tbl_order_detail.`Order_ID` from tbl_order_detail where product_id=" + p_id + ")"; rst2 = stmt2.executeQuery(sw3); rst2.next(); data[i] = new Object[]{new String(rst.getString(2)), new String(rst.getString(3)), new Integer(rst1.getString(1)), new String(rst2.getString(1))}; i++; } ColumnComparator cc = new ColumnComparator(2); Arrays.sort(data, cc); if (i == 0) { table.addCell(""); table.addCell(""); table.addCell(""); table.addCell(""); } else { for (int j = 0; j < y; j++) { Object[] theRow = (Object[]) data[j]; table.addCell((String) theRow[0]); table.addCell((String) theRow[1]); table.addCell((String) theRow[2]); table.addCell((String) theRow[3]); }

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  • SQL Server 2008 - Full Text Query

    - by user208662
    Hello, I have two tables in a SQL Server 2008 database in my company. The first table represents the products that my company sells. The second table contains the product manufacturer’s details. These tables are defined as follows: Product ------- ID Name ManufacturerID Description Manufacturer ------------ ID Name As you can imagine, I want to make this as easy as possible for our customers to query this data. However, I’m having problems writing a forgiving, yet powerful search query. For instance, I’m anticipating people to search based on phonetical spellings. Because of this, the data may not match the exact data in my database. In addition, I think some individuals will search by manufacturer’s name first, but I want the matching product names to appear first. Based on these requirements, I’m currently working on the following query: select p.Name as 'ProductName', m.Name as 'Manufacturer', r.Rank as 'Rank' from Product p inner join Manufacturer m on p.ManufacturerID=m.ID inner join CONTAINSTABLE(Product, Name, @searchQuery) as r Oddly, this query is throwing an error. However, I have no idea why. Squiggles appear to the right of the last parenthesis in management studio. The tool tip says "An expression of non-boolean type specified in a context where a condition is expected". I understand what this statement means. However, I guess I do not know how COntainsTable works. What am I doing wrong? Thank you

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  • How do I superimpose one bitmap image on another in GDI+?

    - by Old Man
    Using GDI+ I've made a heatmap bmp and I'd like to superimpose it on top of my bmp map. I've saved the two bmps to disk, and they look good, I just need a way to put them together. Is there any way to do this, perhaps using the Graphics object? How is transparency/alpa involved? I'm very new to GDI programming so please be as specific as possible.

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  • Why does my simple hello world console app use so much memory?

    - by CodingThunder
    Looking in Process Explorer it uses; Virtual Size: 550,000k , Working Set: 28000k Why does my simple hello world console app use so much memory? I take it the difference between the Working Set and Virtual Size means that difference will be paged to disk? /I am running 64 bit XP. Thanks class Program { static void Main(string[] args) { Console.WriteLine("Hello world"); Console.ReadLine(); } }

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  • Do you ever make a code change and just test rather than trying to fully understand the change you'v

    - by Clay Nichols
    I'm working in a 12 year old code base which I have been the only developer on. There are times that I'll make a a very small change based on an intuition (or quantum leap in logic ;-). Usually I try to deconstruct that change and make sure I read thoroughly the code. However sometimes, (more and more these days) I just test and make sure it had the effect I wanted. (I'm a pretty thorough tester and would test even if I read the code). This works for me and we have surprisingly (compared to most software I see) few bugs escape into the wild. But what I'm wondering is whether this is just the "art" side of coding. Yes, in an ideal world you would exhaustively read every bit of code that your change modified, but I in practice, if you're confident that it only affects a small section of code, is this a common practice? I can obviously see where this would be a disastrous approach in the hands of a poor programmer. But then, I've seen programmers who ostensibly are reading the code and break stuff left and right (in their own code based which only they have been working on).

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  • Determining the chances of an event occurring when it hasn't occurred yet

    - by sanity
    A user visits my website at time t, and they may or may not click on a particular link I care about, if they do I record the fact that they clicked the link, and also the duration since t that they clicked it, call this d. I need an algorithm that allows me to create a class like this: class ClickProbabilityEstimate { public void reportImpression(long id); public void reportClick(long id); public double estimateClickProbability(long id); } Every impression gets a unique id, and this is used when reporting a click to indicate which impression the click belongs to. I need an algorithm that will return a probability, based on how much time has past since an impression was reported, that the impression will receive a click, based on how long previous clicks required. Clearly one would expect that this probability will decrease over time if there is still no click. If necessary, we can set an upper-bound, beyond which we consider the click probability to be 0 (eg. if its been an hour since the impression occurred, we can be pretty sure there won't be a click). The algorithm should be both space and time efficient, and hopefully make as few assumptions as possible, while being elegant. Ease of implementation would also be nice. Any ideas?

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  • C++ variable to const expression

    - by user1344784
    template <typename Real> class A{ }; template <typename Real> class B{ }; //... a few dozen more similar template classes class Computer{ public slots: void setFrom(int from){ from_ = from; } void setTo(int to){ to_ = to; } private: template <int F, int T> void compute(){ using boost::fusion::vector; using boost::fusion::at_c; vector<A<float>, B<float>, ...> v; at_c<from_>(v).operator()(at_c<to_>(v)); //error; needs to be const-expression. }; This question isn't about Qt, but there is a line of Qt code in my example. The setFrom() and setTo() are functions that are called based on user selection via the GUI widget. The root of my problem is that 'from' and 'to' are variables. In my compute member function I need to pick a type (A, B, etc.) based on the values of 'from' and 'to'. The only way I know how to do what I need to do is to use switch statements, but that's extremely tedious in my case and I would like to avoid. Is there anyway to convert the error line to a constant-expression?

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  • Dynamically adjust padding on an image?

    - by Cory
    What I'm basically attempting to do is dynamically change a padding value for a scrubber image based on player position data provided by an app. I have been able to leverage the provided number to dynamically increase the width of a progress overlay image and create a progress bar, but I would like a scrubber diamond at the leading edge of the progress bar. To do this, I have positioned the scrubber diamond at the same starting point as the progress overlay and would like to increase the padding on the diamond at the same rate as the width is increasing for the progress overlay, allowing them to pace each other with the scrubber diamond moving as the song plays. Any help with the script necessary to manipulate padding-left dynamically would be very much appreciated. var progress = Ecoute.playerPosition(); var width = 142.5 / length * progress + 1.63; EcouteSel('Progression').width = width.toString(); EcouteSel('Scrubber').style('padding-left', 'width'); We define progress as the player position, width as a function of the progress and then apply that function to the ID applied to the progress over lay image. But how do I accomplish that for padding-left? style.paddingLeft ...based functions have broken the controller outright. I'm at a loss and any help would be appreciated.

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  • SpringFramework3.0: How to create interceptors that only apply to requests that map to certain contr

    - by Fusion2004
    In it's simplest form, I want an interceptor that checks session data to see if a user is logged in, and if not redirects them to the login page. Obviously, I wouldn't want this interceptor to be used on say the welcome page or the login page itself. I've seen a design that uses a listing of every url to one of two interceptors, one doing nothing and the other being the actual interceptor you want implemented, but this design seems very clunky and limits the ease of extensibility of the application. It makes sense to me that there should be an annotation-based way of using interceptors, but this doesn't seem to exist. My friend has the idea of actually modifying the handler class so that during each request it checks the Controller it is mapping the request to for a new annotation we would create (ex @Interceptor("loginInterceptor") ). A major point of my thinking is the extensibility, because I'd like to later implement similar interceptors for role-based authentication and/or administration authentication. Does it sound like my friend's approach would work for this? Or what is a proper way of going about doing this?

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  • Programmatically Update UITableView in Response to Button Press

    - by Kyle Begeman
    I have a completely custom view that holds a UITableView and a Custom Tab Bar (basically a UIView that contains 6 UIButtons). I am loading data from a plist file, and then I am sorting the data into multiple arrays based on categories (an array for misc items, and array for mail items, etc.) Each button in the tab bar represents a category, and when I press the button I call the custom function "miscSelected" and so on. How can I have the table view completely reload and then display the tableview based on the array selected (select the misc category and the tableview clears itself and loads the misc array data, same for any other category)? The method I have experimented with is created and NSString named "selection" and then in each button function I set selected to equal whatever section I am selecting. In my cellForRoxAtIndexPath method I have this: if ([self.selection isEqualToString:@"All Items"]) { NSArray *mainDataArray = [NSArray arrayWithContentsOfFile:self.plistFile]; NSSortDescriptor *brandDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]; NSArray *sortDescriptors = [NSArray arrayWithObject:brandDescriptor]; self.sortedData = [mainDataArray sortedArrayUsingDescriptors:sortDescriptors]; } else if ([self.selection isEqualToString:@"Misc Items"]){ self.sortedData = [NSArray arrayWithContentsOfFile:self.plistFile]; } cell.itemTitle.text = [[self.sortedData objectAtIndex:indexPath.row] objectForKey:@"name"]; For the sake of example and testing I am simply displaying the same data, just one button displays it in alphabetical order and the other does not. This code works only when I start to scroll down and back up, but it does not actually update on button press. Calling myTable reloadData does not do anything either. Any help would be great, thanks!

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  • Signed_request lost in ASP.NET session, confusing my website

    - by Csabi
    I have an ASP.NET MVC 3 website which is available both from a specific public url, and I'm also making be available as a Facebook App. Inside my website logic, in some places I have to determine whether the current request is from the Facebook-app, or from the public website, because I want to display content based on this environment. So, for eg. if the user is using my site as a facebook-app, then I want to display a picture, and if the user is using my site normally, then I don't wanna display a picture. To determine whether I'm from a Facebook app, I check the "signed_request" in the HttpContext.Request, and store it in the HttpSession to be available for my other actions, not just for that action (url) which is defined for my Facebook app. So when a child-action is executed, I can determine based on the Session, that the website is used as a FB-app or not. The problem happens, when the Session times out, because then althought the logic is still running inside Facebook, my logic thinks it's not inside Facebook. Any advice?

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  • Serving .docx files through Php

    - by user275074
    Hi, I'm having issues when attempting to serve a .docx file using Php. When uploading the file I detect the file mime type and upload the file using the file with the correct extension based on the mime type; e.g. below: application/msword - doc application/vnd.openxmlformats-officedocument.wordprocessingml.document - docx When attempting to serve the files for download, I do the reverse in detecting the extension and serving based on the mime type e.g. public static function fileMimeType($extention) { if(!is_null($extention)) { switch($extention) { case 'txt': return 'text/plain'; break; case 'odt': return 'application/vnd.oasis.opendocument.text'; break; case 'doc': return 'application/msword'; break; case 'docx': return 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'; break; case ('jpg' || 'jpeg'): return 'image/jpeg'; break; case 'png': return 'image/png'; break; case 'pdf': return 'application/pdf'; break; default: break; } } } All files appear to download correctly and open fine but when attempting to open a docx file, Word (on multiple files) throws a error stating the file is corrupt. Any ideas would be great, thanks.

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  • How to fix windows 7 loader?

    - by Adio
    I have an HD 250 Gb It is portioned to C,D,E C has 50 GB D has 50 GB and the rest is given to E, On C I have Windows 7, I decided to install Opensuse On E. I have installed Opensuse Successfully. Now Opensuse loader shows Windows7 option when I it loads but, when I chose to load windows 7 I get " A Disk read error occured, press ctrl+alt+e to restart". Does any one has an Idea How to fix windows 7 and keep Opensuse ? My Opensuse is 12.2. Thanks

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  • What is the most efficient way to handle points / small vectors in JavaScript?

    - by Chris
    Currently I'm creating an web based (= JavaScript) application thata is using a lot of "points" (= small, fixed size vectors). There are basically two obvious ways of representing them: var pointA = [ xValue, yValue ]; and var pointB = { x: xValue, y: yValue }; So translating my point a bit would look like: var pointAtrans = [ pointA[0] + 3, pointA[1] + 4 ]; var pointBtrans = { x: pointB.x + 3, pointB.y + 4 }; Both are easy to handle from a programmer point of view (the object variant is a bit more readable, especially as I'm mostly dealing with 2D data, seldom with 3D and hardly with 4D - but never more. It'll allways fit into x,y,z and w) But my question is now: What is the most efficient way from the language perspective - theoretically and in real implementations? What are the memory requirements? What are the setup costs of an array vs. an object? ... My target browsers are FireFox and the Webkit based ones (Chromium, Safari), but it wouldn't hurt to have a great (= fast) experience under IE and Opera as well...

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