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  • Recalculate Counter Cache of 120k Records [Rails / ActiveRecord]

    - by Sebastian
    The following situation: I have a poi model, which has many pictures (1:n). I want to recalculate the counter_cache column, because the values are inconsistent. I've tried to iterate within ruby over each record, but this takes much too long and quits sometimes with some "segmentation fault" bugs. So i wonder, if its possible to do this with a raw sql query?

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  • Using subselect to accomplish LEFT JOIN

    - by Andre
    Is is possible to accomplish the equivalent of a LEFT JOIN with subselect where multiple columns are required. Here's what I mean. SELECT m.*, (SELECT * FROM model WHERE id = m.id LIMIT 1) AS models FROM make m As it stands now doing this gives me a 'Operand should contain 1 column(s)' error. Yes I know this is possible with LEFT JOIN, but I was told it was possible with subselect to I'm curious as to how it's done.

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  • plot matrix missing points in different color using gnuplot

    - by kitt
    I have a file 'matrix.dat': 1 2 3 4 5 5 - 3 4 5 - 4 5 B - 1 B 2 B 3 - 3 2 - 3 I want to plot numbers using palette, '-' using white color and 'B' using black color. In gnuplot, I use this palette (blue - cyan - green - orange - red): set palette model HSV functions 0.666*(1-gray), 1, 1 And set '-' as missing data: set datafile missing "-" plot 'matrix.dat' matrix with image Now I can only plot numbers and '-' in correct colors.

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  • How to save in Hindi in database using MVC application

    - by user219315
    I have a MVC application and using the entity framework model for MYSQL database. I what to save hindi text in database. When I using the hindi text then it is showing ?? in database. I am using ckeditor to enter the text How can I save the hindi text.I have also changed the collation to utf-8. Thanks supriya

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  • Core Data: Overkill for simple, static UITableView-based iPhone App?

    - by David Foster
    Hello! I have a rather simple iPhone app consisting of numerous views containing a single, grouped table view. These views are held together in navigation controllers which are grouped in a tab bar. Simple stuff. My table views do little more than list text (like "Dog", "Cat" and "Weasel") and this data is being served from a collection of plists. It's perhaps worth mentioning too that these tables are 'static' in the sense that their data is pre-determined and will only ever be amended—and if so, very rarely indeed—by the developer (in this case, moi). This rudimentary approach has reached its limits though, and I think I'm going to need something a bit more relational. I have worked a tad with Core Data in the past, but only with apps whose data is determined by user input. I have four closely related questions: Is Core Data overkill for an app consisting mainly of a selection of simple table views? Do you recommend using Core Data to manage data which is predetermine and extremely unlikely to ever change? Can one lock Core Data down so that its data can't change, thereby relinquishing my responsibility as the developer to handle the editing and saving of the managed object context? How do I go about giving Core Data my predetermined data, and in a format I know that it can work with? Thanks a bunch guys.

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  • Recommend me an architecture for this Facebook application

    - by andybaird
    Firstly, this question is subjective. There is not a right answer for this question and it really depends on what works for you. I'm hoping to use this thread as a breeding ground for ideas. I hope this is acceptable in this medium. I'm working on building a Facebook app that will be replacing an already popular app that gets ~50k hits a day. The original app is using a very typical LAMP setup with help from some Zend libraries for database layer extraction. For the most part the app worked well, except to solve a lot of issues I ended up fragmenting tables to speed things up. As a result, I couldn't do a lot of things with the app that I wanted to (namely any processing using aggregate data that needed to be returned quickly) So I'm starting to design plans for the next version of this application, and I have a whole bunch of new and cool features that I know would choke my current setup. I'm looking for technological recommendations of data storage methods that scale well. The database does not necessarily need to be relational, simple key/value storage would suffice (although at present time I know little to nothing about KV stores) What's your recommendation? How would you tackle this? I'd like to take a completely free approach to this -- although I am most familiar and comfortable using PHP, I want to leave all technical options open.

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  • Struts2 data tranfer from Jsp to Action using Complex Objects

    - by indra
    Hi, how to use Model-driven or Object-backed approaches to map Complex Object with depth more than one. for example, I have action class with property User object and USer has a address object as its property. Address has street name as property. like .. User.address.streetName In JSP, using s:textfield or other tags how can I represent street name.? Thanks

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  • XQuery performance in SQL Server

    - by Carl Hörberg
    Why does this quite simple xquery takes 10min to execute in sql server (the 2mb xml document stored in one column) compared to 14 seconds when using oxygen/file based querying? SELECT model.query('declare default element namespace "http://www.sbml.org/sbml/level2"; for $all_species in //species, $all_reactions in //reaction where data($all_species/@compartment)="plasma_membrane" and $all_reactions/listOfReactants/speciesReference/@species=$all_species/@id return <result>{data($all_species/@id)}</result>') from sbml;

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  • Classes to Entities; Like-class inheritence problems

    - by Stacey
    Beyond work, some friends and I are trying to build a game of sorts; The way we structure some of it works pretty well for a normal object oriented approach, but as most developers will attest this does not always translate itself well into a database persistent approach. This is not the absolute layout of what we have, it is just a sample model given for sake of representation. The whole project is being done in C# 4.0, and we have every intention of using Entity Framework 4.0 (unless Fluent nHibernate can really offer us something we outright cannot do in EF). One of the problems we keep running across is inheriting things in database models. Using the Entity Framework designer, I can draw the same code I have below; but I'm sure it is pretty obvious that it doesn't work like it is expected to. To clarify a little bit; 'Items' have bonuses, which can be of anything. Therefore, every part of the game must derive from something similar so that no matter what is 'changed' it is all at a basic enough level to be hooked into. Sounds fairly simple and straightforward, right? So then, we inherit everything that pertains to the game from 'Unit'. Weights, Measures, Random (think like dice, maybe?), and there will be other such entities. Some of them are similar, but in code they will each react differently. We're having a really big problem with abstracting this kind of thing into a database model. Without 'Enum' support, it is proving difficult to translate into multiple tables that still share a common listing. One solution we've depicted is to use a 'key ring' type approach, where everything that attaches to a character is stored on a 'Ring' with a 'Key', where each Key has a Value that represents a type. This works functionally but we've discovered it becomes very sluggish and performs poorly. We also dislike this approach because it begins to feel as if everything is 'dumped' into one class; which makes management and logical structure difficult to adhere to. I was hoping someone else might have some ideas on what I could do with this problem. It's really driving me up the wall; To summarize; the goal is to build a type (Unit) that can be used as a base type (Table per Type) for generic reference across a relatively global scope, without having to dump everything into a single collection. I can use an Interface to determine actual behavior so that isn't too big of an issue. This is 'roughly' the same idea expressed in the Entity Framework.

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  • Access 2007 and Special/Unicode Characters in SQL

    - by blockcipher
    I have a small Access 2007 database that I need to be able to import data from an existing spreadsheet and put it into our new relational model. For the most part this seems to work pretty well. Part of the process is attempting to see if a record already exists in a target table using SQL. For example, if I extract book information out of the current row in the spreadsheet, it may contain a title and abstract. I use SQL to get the ID of a matching record, if it exists. This works fine except when I have data that's in a non-English language. In this case, it seems that there is some punctuation that is causing me problems. At least I think it's punctuation as I do have some fields that do not have punctuation and are non-English that do not give me any problems. Is there a built-in function that can escape these characters? Currently I have a small function that will escape the single quote character, but that isn't enough. Or, is there a list of Unicode characters that can interfere with how SQL wants data quoted? Thanks in advance.

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  • PHP + MYSQLI: Variable parameter/result binding with prepared statements.

    - by Brian Warshaw
    In a project that I'm about to wrap up, I've written and implemented an object-relational mapping solution for PHP. Before the doubters and dreamers cry out "how on earth?", relax -- I haven't found a way to make late static binding work -- I'm just working around it in the best way that I possibly can. Anyway, I'm not currently using prepared statements for querying, because I couldn't come up with a way to pass a variable number of arguments to the bind_params() or bind_result() methods. Why do I need to support a variable number of arguments, you ask? Because the superclass of my models (think of my solution as a hacked-up PHP ActiveRecord wannabe) is where the querying is defined, and so the find() method, for example, doesn't know how many parameters it would need to bind. Now, I've already thought of building an argument list and passing a string to eval(), but I don't like that solution very much -- I'd rather just implement my own security checks and pass on statements. Does anyone have any suggestions (or success stories) about how to get this done? If you can help me solve this first problem, perhaps we can tackle binding the result set (something I suspect will be more difficult, or at least more resource-intensive if it involves an initial query to determine table structure).

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  • C# Select clause returns system exception instead of relevant object

    - by Kashif
    I am trying to use the select clause to pick out an object which matches a specified name field from a database query as follows: objectQuery = from obj in objectList where obj.Equals(objectName) select obj; In the results view of my query, I get: base {System.SystemException} = {"Boolean Equals(System.Object)"} Where I should be expecting something like a Car, Make, or Model Would someone please explain what I am doing wrong here? The method in question can be seen here: // this function searches the database's table for a single object that matches the 'Name' property with 'objectName' public static T Read<T>(string objectName) where T : IEquatable<T> { using (ISession session = NHibernateHelper.OpenSession()) { IQueryable<T> objectList = session.Query<T>(); // pull (query) all the objects from the table in the database int count = objectList.Count(); // return the number of objects in the table // alternative: int count = makeList.Count<T>(); IQueryable<T> objectQuery = null; // create a reference for our queryable list of objects T foundObject = default(T); // create an object reference for our found object if (count > 0) { // give me all objects that have a name that matches 'objectName' and store them in 'objectQuery' objectQuery = from obj in objectList where obj.Equals(objectName) select obj; // make sure that 'objectQuery' has only one object in it try { foundObject = (T)objectQuery.Single(); } catch { return default(T); } // output some information to the console (output screen) Console.WriteLine("Read Make: " + foundObject.ToString()); } // pass the reference of the found object on to whoever asked for it return foundObject; } } Note that I am using the interface "IQuatable<T>" in my method descriptor. An example of the classes I am trying to pull from the database is: public class Make: IEquatable<Make> { public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual IList<Model> Models { get; set; } public Make() { // this public no-argument constructor is required for NHibernate } public Make(string makeName) { this.Name = makeName; } public override string ToString() { return Name; } // Implementation of IEquatable<T> interface public virtual bool Equals(Make make) { if (this.Id == make.Id) { return true; } else { return false; } } // Implementation of IEquatable<T> interface public virtual bool Equals(String name) { if (this.Name.Equals(name)) { return true; } else { return false; } } } And the interface is described simply as: public interface IEquatable<T> { bool Equals(T obj); }

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  • Mocking HtmlHelper throws NullReferenceException

    - by Matt Austin
    I know that there are a few questions on StackOverflow on this topic but I haven't been able to get any of the suggestions to work for me. I've been banging my head against this for two days now so its time to ask for help... The following code snippit is a simplified unit test to demonstrate what I'm trying to do, which is basically call RadioButtonFor in the Microsoft.Web.Mvc assembly in a unit test. var model = new SendMessageModel { SendMessageType = SendMessageType.Member }; var vd = new ViewDataDictionary(model); vd.TemplateInfo = new TemplateInfo { HtmlFieldPrefix = string.Empty }; var controllerContext = new ControllerContext(new Mock<HttpContextBase>().Object, new RouteData(), new Mock<ControllerBase>().Object); var viewContext = new Mock<ViewContext>(new object[] { controllerContext, new Mock<IView>().Object, vd, new TempDataDictionary(), new Mock<TextWriter>().Object }); viewContext.Setup(v => v.View).Returns(new Mock<IView>().Object); viewContext.Setup(v => v.ViewData).Returns(vd).Callback(() => {throw new Exception("ViewData extracted");}); viewContext.Setup(v => v.TempData).Returns(new TempDataDictionary()); viewContext.Setup(v => v.Writer).Returns(new Mock<TextWriter>().Object); viewContext.Setup(v => v.RouteData).Returns(new RouteData()); viewContext.Setup(v => v.HttpContext).Returns(new Mock<HttpContextBase>().Object); viewContext.Setup(v => v.Controller).Returns(new Mock<ControllerBase>().Object); viewContext.Setup(v => v.FormContext).Returns(new FormContext()); var mockContainer = new Mock<IViewDataContainer>(); mockContainer.Setup(x => x.ViewData).Returns(vd); var helper = new HtmlHelper<ISendMessageModel>(viewContext.Object, mockContainer.Object, new RouteCollection()); helper.RadioButtonFor(m => m.SendMessageType, "Member", cssClass: "selector"); If I remove the cssClass parameter then the code works ok but fails consistently when adding additional parameters. I've tried every combination of mocking, instantiating concrete types and using fakes that I can think off but I always get a NullReferenceException when I call RadioButtonFor. Any help hugely appreciated!!

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  • How to generate spectrum color palettes

    - by ddimitrov
    Is there an easy way to convert between color models in Java (RGB, HSV and Lab). Assuming RGB color model: How do I calculate black body spectrum color palette? I want to use it for a heatmap chart. How about single-wavelength spectrum? Edit: I found that the ColorSpace class can be used for conversions between RGB/CIE and many other color models.

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  • Are there any modeling tools that can visually generate jpa or sql queries?

    - by Shervin
    Does anyone know of a tool like PowerArchitect or SquirrelSQL or maybe eclipse plugin that lets you also generate jpa/sql queries? Imagine you choosing your database, or your entity beans, and the modeling would reverse engineer your database/entity model, so that you could visually just choose the columns you wanted to select, and it would generate jpa or sql queries for you. For instance choosing A.b and X.y would generate something like this: select a.b, x.y from A a, X x join ......

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  • Entity framework unit testing with sqlite

    - by Marcus Malmgren
    Is it possible to unit test Entity Framework v2 repositories with SqLite? Is this only possible if my entities are plain Poco and not automatically generated by Entity Framework? I've generated a entity model from SqlServer and in the generated .edmx file i found this in section SSDL content: Provider="System.Data.SqlClient". Correct me if I am wrong, but shouldnt that be System.Data.SQLite in order to work with sqlite?

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  • Sparse (Pseudo) Infinite Grid Data Structure for Web Game

    - by Ming
    I'm considering trying to make a game that takes place on an essentially infinite grid. The grid is very sparse. Certain small regions of relatively high density. Relatively few isolated nonempty cells. The amount of the grid in use is too large to implement naively but probably smallish by "big data" standards (I'm not trying to map the Internet or anything like that) This needs to be easy to persist. Here are the operations I may want to perform (reasonably efficiently) on this grid: Ask for some small rectangular region of cells and all their contents (a player's current neighborhood) Set individual cells or blit small regions (the player is making a move) Ask for the rough shape or outline/silhouette of some larger rectangular regions (a world map or region preview) Find some regions with approximately a given density (player spawning location) Approximate shortest path through gaps of at most some small constant empty spaces per hop (it's OK to be a bad approximation often, but not OK to keep heading the wrong direction searching) Approximate convex hull for a region Here's the catch: I want to do this in a web app. That is, I would prefer to use existing data storage (perhaps in the form of a relational database) and relatively little external dependency (preferably avoiding the need for a persistent process). Guys, what advice can you give me on actually implementing this? How would you do this if the web-app restrictions weren't in place? How would you modify that if they were? Thanks a lot, everyone!

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  • What arguments to use to explain why a SQL DB is far better then a flat file

    - by jamone
    The higher ups in my company were told by good friends that flat files are the way to go, and we should switch from MS SQL server to them for everything we do. We have over 300 servers and hundreds of different databases. From just the few I'm involved with we have 10 billion records in quite a few of them with upwards of 100k new records a day and who knows how many updates... Me and a couple others need to come up with a response saying why we shouldn't do this. Most of our stuff is ASP.NET with some legacy ASP. We thought that making a simple console app that tests/times the same interactions between a flat file (stored on the network) and SQL over the network doing large inserts, searches, updates etc along with things like network disconnects randomly. This would show them how bad flat files can be espically when you are dealing with millions of records. What things should I use in my response? What should I do with my demo code to illustrate this? My sort list so far: Security Concurent access Performance with large ammounts of data Ammount of time to do such a massive rewrite/switch Lack of transactions PITA to map relational data to flat files I fear that this will be a great post on the Daily WTF someday if I can't stop it now.

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  • What arguments to use to explain why SQL Server is far better then a flat file

    - by jamone
    The higher ups in my company were told by good friends that flat files are the way to go, and we should switch from SQL Server to them for everything we do. We have over 300 servers and hundreds of different databases. From just the few I'm involved with we have 10 billion records in quite a few of them with upwards of 100k new records a day and who knows how many updates... Me and a couple others need to come up with a response saying why we shouldn't do this. Most of our stuff is ASP.NET with some legacy ASP. We thought that making a simple console app that tests/times the same interactions between a flat file (stored on the network) and SQL over the network doing large inserts, searches, updates etc along with things like network disconnects randomly. This would show them how bad flat files can be especially when you are dealing with millions of records. What things should I use in my response? What should I do with my demo code to illustrate this? My sort list so far: Security Concurrent access Performance with large amounts of data Amount of time to do such a massive rewrite/switch Lack of transactions PITA to map relational data to flat files NTFS doesn't support tons of files in a directory well I fear that this will be a great post on the Daily WTF someday if I can't stop it now.

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  • Initialize virtual attributes

    - by Horace Loeb
    I have an IncomingEmail model with an attachments virtual attribute: class IncomingEmail < ActiveRecord::Base attr_accessor :attachments end I want the attachments virtual attribute to be initialized to [] rather than nil so that I can do: >> i = IncomingEmail.new => #<IncomingEmail id: nil,...) >> i.attachments << "whatever" Without first setting i.attachments to [] (put another way, I want this virtual attribute to default to an empty array rather than nil)

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  • Where are the menu,header,footer loaded in an MVC structures

    - by Saif Bechan
    I am creating an framework in PHP, and i am using and MVC structure. My link look something like this: mydomain.com/controller/action So this link loads a controller, which loads the needed action. Now my page needs a header, footer, and it has a menu which is in the database. Where do i load all these things. Is this the job of the controller, or the job of the model.

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