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• What database strategy to choose for a large web application

  - by Snoopy

  I have to rewrite a large database application, running on 32 servers. The hardware is up to date, each machine has two quad core Xeon and 32 GByte RAM. The database is multi-tenant, each customer has his own file, around 5 to 10 GByte each. I run around 50 databases on this hardware. The app is open to the web, so I have no control on the load. There are no really complex queries, so SQL is not required if there is a better solution. The databases get updated via FTP every day at midnight. The database is read-only. C# is my favourite language and I want to use ASP.NET MVC. I thought about the following options: Use two big SQL servers running SQL Server 2012 to serve the 32 servers with data. On the 32 servers running IIS hosting providing REST services. Denormalize the database and use Redis on each webserver. Use booksleeve as a Redis client. Use a combination of SQL Server and Redis Use SQL Server 2012 together with Hadoop Use Hadoop without SQL Server What is the best way for a read-only database, to get the best performance without loosing maintainability? Does Map-Reduce make sense at all in such a scenario? The reason for the rewrite is, the old app written in C++ with ISAM technology is too slow, the interfaces are old fashioned and not nice to use from an website, especially when using ajax. The app uses a relational datamodel with many tables, but it is possible to write one accerlerator table where all queries can be performed on, and all other information from the other tables are possible by a simple key lookup.

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• How practical to change MVC app from traditional authentication to cookieless?

  - by Phil.Wheeler

  I have an application written in MVC that uses your regular .Net Forms Authentication. There's nothing particularly new or exciting going on with it. My client has now asked that users be able to log in to the app on the same machine but in different browsers, or different tabs within the same browser. To my mind, he's asking for a scope change to have authentication moved to cookieless instead of its current design. Not having had any experience with doing this in MVC, I'm curious to know before I get started how much hurt I'm in for by trying this. Are there better ways to do it? What should I consider? Any advice appreciated.

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• Is XSLT worth investing time in and are there any actual alternatives?

  - by Keeno

  I realize this has been a few other questions on this topic, and people are saying use your language of choice to manipulate the XML etc etc however, not quite fit my question exactly. Firstly, the scope of the project: We want to develop platform independent e-learning, currently, its a bunch of HTML pages but as they grow and develop they become hard to maintain. The idea: Generate up an XML file + Schema, then produce some XSLT files that process the XML into the eLearning modiles. XML to HTML via XSLT. Why: We would like the flexibilty to be able to easy reformat the content (I realize CSS is a viable alternative here) If we decide to alter the pages layout or functionality in anyway, im guessing altering the "shared" XSLT files would be easier than updating the HTML files. So far, we have about 30 modules, with up to 10-30 pages each Depending on some "parameters" we could output drastically different page layouts/structures, above and beyond what CSS can do Now, all this has to be platform independent, and to be able to run "offline" i.e. without a server powering the HTML Negatives I've read so far for XSLT: Overhead? Not exactly sure why...is it the compute power need to convert to HTML? Difficult to learn Better alternatives Now, what I would like to know exactly is: are there actually any viable alternatives for this "offline"? Am I going about it in the correct manner, do you guys have any advice or alternatives. Thanks!

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• Is it a good idea to use MySQL and Neo4j together?

  - by Sanoj

  I will make an application with a lot of similar items (millions), and I would like to store them in a MySQL database, because I would like to do a lot of statistics and search on specific values for specific columns. But at the same time, I will store relations between all the items, that are related in many connected binary-tree-like structures (transitive closure), and relation databases are not good at that kind of structures, so I would like to store all relations in Neo4j which have good performance for this kind of data. My plan is to have all data except the relations in the MySQL database and all relations with item_id stored in the Neo4j database. When I want to lookup a tree, I first search the Neo4j for all the item_id:s in the tree, then I search the MySQL-database for all the specified items in a query that would look like: SELECT * FROM items WHERE item_id = 45 OR item_id = 345435 OR item_id = 343 OR item_id = 78 OR item_id = 4522 OR item_id = 676 OR item_id = 443 OR item_id = 4255 OR item_id = 4345 Is this a good idea, or am I very wrong? I haven't used graph-databases before. Are there any better approaches to my problem? How would the MySQL-query perform in this case?

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• Spring MVC: should service layer be returning operation specific DTO's ?

  - by arrages

  In my Spring MVC application I am using DTO in the presentation layer in order to encapsulate the domain model in the service layer. The DTO's are being used as the spring form backing objects. hence my services look something like this: userService.storeUser(NewUserRequestDTO req); The service layer will translate DTO - Domain object and do the rest of the work. Now my problem is that when I want to retrieve a DTO from the service to perform say an Update or Display I can't seem to find a better way to do it then to have multiple methods for the lookup that return different DTO's like... EditUserRequestDTO userService.loadUserForEdit(int id); DisplayUserDTO userService.loadUserForDisplay(int id); but something does not feel right about this approach. The reason do have separate DTO's is that DisplayUserDTO is strongly typed to be read only and also there are many properties of user that are entities from a lookup table in the db (like city and state) so the DisplayUserDTO would have the string description of the properties while the EditUserRequestDTO will have the id's that will back the select drop down lists in the forms. What do you think? thanks

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• Why does GetTextFace always return "system"?

  - by user545142

  I am trying to get the font of controls in other applications. When I try WM_GETFONT, it returns 0. This my code: [DllImport("User32.DLL")] public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam); IntPtr fx = SendMessage(button1.Handle, 0x31, 0, 0); When I use GetTextFace with a button, it always returns "system". This is my code: StringBuilder Buff = new StringBuilder(256); IntPtr dc = GetDCEx(button1.Handle, IntPtr.Zero, DeviceContextValues.Window |DeviceContextValues.Cache | DeviceContextValues.ClipSiblings | DeviceContextValues.IntersectRgn); IntPtr hfont = GetTextFace(dc, 256, Buff); Of course I'm sure I changed the font type. How can I solve this problem? I am using C# under Windows 7.

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• O'Reilly book clarification on 2d linear system

  - by Eric

  The Oreilly book "Learning openCV" states at page 356 : Quote Before we get totally lost, let’s consider a particular realistic situation of taking measurements on a car driving in a parking lot. We might imagine that the state of the car could be summarized by two position variables, x and y, and two velocities, vx and vy. These four variables would be the elements of the state vector xk. Th is suggests that the correct form for F is: x = [ x; y; vx; vy; ]k F = [ 1, 0, dt, 0; 0, 1, 0, dt; 0, 0, 1, 0; 0, 0, 0, 1; ] It seems natural to put 'dt' just there in the F matrix but I just don't get why. What if I have a n states system, how would I spray some "dt" in the F matrix?

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• Visual C++/CLI "An unhandled exception of type 'System.StackOverflowException' occurred in"

  - by JennyWong

  Hi, I have a game I am making, it is giving me this message... "An unhandled exception of type 'System.StackOverflowException' occurred in game.exe" To explain...I have a 2D array with 9 different opening moves and I am getting a random number to use as the array reference to retrieve the details needed for a move... you may get the same move again - but that's illegal. the move may be illegal for other reasons too So to try and fix this, I am calling the function again from within the function. The error occurs very randomly Is this bad practise to call a function from within itself? What would be a better way to randomly row from a 2D array, AND if it isn't accept to get another one.... Or better still, how can I retrieve a random LEGAL move?

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• Architecting a generic search result web control

  - by Bartek Tatkowski

  In a project I'm currently working for we've stumbled upon the need for several kinds of search results presentation controls. The search result are similar, but not identical. For example, in the "office search" result we might want to present the office name and location, while in the "document search" could contain document name, author and publishing date. These fields should be sortable. My current strategy is to employ the Factory pattern and do something like this: ISearchResult officeResults = SearchResultFactory.CreateOfficeSearchResults(data); ISearchResult documentResults = SearchResultFactory.CreateDocumentSearchResults(data); The problem is: I don't know how to implement the markup code. Should I just do Controls.Add(officeResults); in the containing page? Or is there some ASPX trickery to create generic web controls? Or maybe I'm overthinking this and just should create five classes? ;)

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• Photo printing API system?

  - by webdestroya

  I am looking for options to provide customers on my website a way to order prints for photos. (It is a photo sharing site, so it needs to be automated, I don't want any portfolio sites that require uploads and what not). Basically it just needs where I send them the photos, the address, (and possibly billing info) and they make the prints and mail them out. I have searched all over the place for such a system, but none seem to offer what I want. I tried hacking snapfish (which worked, but it says "Return to Picasa" on the buttons, which makes it sort of lame...) Any ideas?

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• Platform Framework and Middle-ware

  - by Walidix

  I really want to fix the meanings of this terms.This is what I know about them: Platform: is an environment that allows an application to run and it is usually composite by hardware and software e.g. your machine with your OS installed on it. However some software stack are also called as platform like Java Platform. Framework: is design-oriented. That is, it defines a skeleton of an application type. Also it saves time by offering, through an API, the common functionalities that a kind of applications must implement. Moreover a Framework include a software components that manage the application life-cycle. Middle-ware: is a software that offers services to an application in order to let it inter-operates with other applications or supports different platforms. Middle-ware can be a part of a framework. Is there something wrong or missing ?

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• Operating system question

  - by ual

  I recently asked myself: If a program, like Mozilla Firefox for example, is started - the control must be somehow given to it. But when the program crashes, why doesn't my whole system crash like in early Windows version? How can Windows take back the control from the program, or even not give it to it fully? (Note: This is not my homework; I go to school but in my informatics class are really only guys that would answer with "Can I eat that?" when I ask them about kernels. Same with my teacher.)

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• Is there an equivalent to COM on *nix systems ? If not, what was the *nix approach to re-usability?

  - by RyBolt

  I have an understanding of windows COM and the ideas behind it. I am trying to understand if *nix systems even have an equivalent or why they don't?

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• Using AMQP to collect events

  - by synapse

  Does AMQP has any advantages over an ad-hoc implementation for a simple stats gathering scenario? It works like this - clients send events (more than we care to put into persistent storage) to (several) web workers, the workers aggrregate them and write to a single database. I don't think I should consider using AMQP for this because I'll still need web workers to receive events from clients through HTTP and to publish them. Am I missing something?

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• Operating system scheduler question

  - by ual

  I recently asked myself: If a program, like Mozilla Firefox for example, is started - the control must be somehow given to it. But when the program crashes, why doesn't my whole system crash like in early Windows version? How can Windows take back the control from the program, or even not give it to it fully? (Note: This is not my homework; I go to school but in my informatics class are really only guys that would answer with "Can I eat that?" when I ask them about kernels. Same with my teacher.)

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• Is it possible to see computer scheem from programm?

  - by Ole Jak

  So I want to see all the computer scheem like (for ex motherbord, how it is connected to video card) what parts of it are used and how data fluws between them how they are connected where is any thing going wrong or beter than expected. For any computer configuration. Is there any lib or sdk for working with such.. such data?

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• Start with remoting or with WCF

  - by Sheldon

  Hi. I'm just starting with distributed application development. I need to create (all by myself) an enterprise application for document management. That application will run on an intranet (within the firewall, no internet access is required now, BUT is probably that will be later). The application needs to manage images that will be stored within MySQL Server (as blobs) and those images will be then recovered by the app and eventually one or more of them will be converted to PDF. Performance is the most important non-functional requirement. I have a couple of doubts. What do you suggest to use, .NET Remoting or WCF over TCP-IP (I think second one is the best for the moment I need to expose the business logic over internet, changing the protocol). Where do you suggest to make the transformation of the images to pdf files, I'm using iText. (I have thought to have the business logic stored within the IIS and exposed via WCF, and that business logic to be responsible of getting the images and transforming them to PDF, that because the IIS and the MySQL Server are the same physical machine). I ask about where to do the transformation because the app must be accessible from multiple devices, and for example, for mobile devices, the pdf maybe is not necessary. Thank you very much in advance.

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• App Engine and MySQL

  - by Shubhkarman

  I just wanted to ask if we can access an external MySQL server from Google App Engine...

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• linux's fork and system resources

  - by Dmitry Bespalov

  Suppose I have following code in linux: int main() { FILE* f = fopen("file.txt", "w"); fork(); fwrite("A", 1, 1, f); fclose(f); return 0; } What I know about fork from documentation, is that it makes the copy of current process. It copies state of the memory as well, so *f should be equal in both instances. But what happens with system resources, such as a file handle? In this example I open the file with write intentions, so only one instance can write into file, right? Which of the instances will actually write into file? Who should care further about the file handle, and call fclose() ?

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• University System Automation, how the internal system of a university works?

  - by Zia ur Rahman

  Hay dear! Suppose we want to make a software , we want to automate the system of university. Suppose a student apply in the university for a certain course, now the question is where the application form of the student will go and what process will be done on this form and then what is the next stage of this form and why it will go to the next stage? Now I hope you have got my point. I need information from the enrollment of a student to its pass out. Or provide a state transition diagram or Data flow diagram. I will be very thankful.

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• What is a 'better' approach to query/save from server: DTO or Wcf Data Services?

  - by bonefisher

  From my perspective, the Data Services and their query approach is useful when querying simple object graphs from your server-side domain model. But when you want to query complex dependencies I couldn't create anything good out of it. The classic DTO approach is fine-grained and can handle everything, but the downside is that you have to create Dto classes for every type of server-request which is time consuming and you have to synchronize the Dto type with your domain entity/business logic.

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• testing the controller in asp.net mvc

  - by csetzkorn

  Hi, I would like to test the validation of submitted DTO. This is the bare bone of a controller create action: [AcceptVerbs(HttpVerbs.Post)] public RedirectToRouteResult Create(SomeDTO SomeDTO) { SomeObject SomeObject = null; try { SomeObject = this.RepositoryService.getSomeObjectRepository().Create(SomeDTO, this.RepositoryService); } catch (BrokenRulesException ex) { ex.AddModelStateErrors(ModelState, "Model"); } catch (Exception e) { ModelState.AddModelError("Exception", e.Message); } TempData["ViewData"] = ViewData; TempData["SomeDTO "] = SomeDTO; return ModelState.IsValid ? RedirectToAction("SomeObjectDetail", new { Id = SomeObject.Id }) : RedirectToAction("Form"); } The mechanics , although not relevant, is as follows: I have a strongly typed view = form which submits a dto to this action which either returns the form or the details page of the created object. I would like to unit test whether the Model contains certain key/errorMessage combinations given some invalid dto. Did someone do similar stuff? Any pointers would be very much appreciated. Thanks. Best wishes, Christian

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• Avoiding mass propagation of properties and events for exposure to ViewModels.

  - by firoso

  I have an MVVM application I am developing that is to the point where I'm ready to start putting together a user interface (my client code is largely functional) I'm now running into the issue that I'm trying to get my application data to where I need it so that it can be consumed by the view model and then bound to the view. Unfortunately, it seems that I've either got a few structural oversights, or I'm just going to have to face the reality that I need to be propogating events and raising excessive amounts of errors to notify view models that thier properties have changed. Let me go into some examples of my issue: I have a class "Unit" contained in a class "Test", contained in a class "Session" contained in a class "TestManager" which is contained in "TestDataModel" which is utilized by "TestViewModel" which is databound to by my "TestView" .... WHOA. Now, consider that Unit (the bottom of the heiarchy) has a property called "Results" that is updated periodically, I want to expose that to my viewmodel and then databind it to my view, trouble is, the only way I can really think to do this is to perpetuate events WAY up a chain that say "I've been updated!" and then request the new value... This seems like an aweful way to do this. Alternatively, I could register a static event and raise it, and have the appropriate "Unit view model" grab the event and request the update. This SEEMS better... but... static events? Is that a taboo idea? Also, having an expression like: TestDataModel.TestManager.Session.Test.Unit.Results[i] Seems REALLY gross to have on a View Model. I know this all reeks of a bad design issue, but I can't figure out what I did wrong? Should I be using more singleton/container controlled lifetimes type objects? Register object instances with static helper containers? Obviously these are hard questions to answer without being intimate with the existing structure, but if you've run into situations like this, what did you do to refactor? Should I just live with this, add mass events, and propogate them?

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• import csv file/excel into sql database asp.net

  - by kiev

  Hi everyone! I am starting a project with asp.net visual studio 2008 / SQL 2000 (2005 in future) using c#. The tricky part for me is that the existing DB schema changes often and the import files columns will all have to me matched up with the existing db schema since they may not be one to one match on column names. (There is a lookup table that provides the tables schema with column names I will use) I am exploring different ways to approach this, and need some expert advice. Is there any existing controls or frameworks that I can leverage to do any of this? So far I explored FileUpload .NET control, as well as some 3rd party upload controls to accomplish the upload such as SlickUpload but the files uploaded should be < 500mb Next part is reading of my csv /excel and parsing it for display to the user so they can match it with our db schema. I saw CSVReader and others but for excel its more difficult since I will need to support different versions. Essentially The user performing this import will insert and/or update several tables from this import file. There are other more advance requirements like record matching but and preview of the import records, but I wish to get through understanding how to do this first. Update: I ended up using csvReader with LumenWorks.Framework for uploading the csv files.

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• Is it possible to use the Spread Toolkit on Amazon EC2?

  - by Dave Viner

  The Spread Toolkit (http://www.spread.org) allows for easy distributed messaging using publish-subscribe semantics. Is it possible to use this toolkit on EC2? What other pub-sub message buses can be used on EC2 (other than Amazon's SQS)?

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