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• which is better, creating a materialized view or a new table?

  - by Carson

  I have some demanding mysql queries that are needed to grap same up-to-date datasets from 5-7 mysql tables. I am thinking of creating a table or materialized view to gather all demanding columns from other tables, so as to increase performance. If I create that table, I may need to do extra insert / update / delete operation each time other tables updated. if I create materialized view, I am worrying if the performance can be greatly improved. Because data from other tables are changing very frequently. Most likely, the view may need to be created first everytime before selecting it. Any ideas? e.g. how to cache? other extra measures I can do?

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• JavaScript Module Pattern - What about using "return this"?

  - by Rob

  After doing some reading about the Module Pattern, I've seen a few ways of returning the properties which you want to be public. One of the most common ways is to declare your public properties and methods right inside of the "return" statement, apart from your private properties and methods. A similar way (the "Revealing" pattern) is to provide simply references to the properties and methods which you want to be public. Lastly, a third technique I saw was to create a new object inside your module function, to which you assign your new properties before returning said object. This was an interesting idea, but requires the creation of a new object. So I was thinking, why not just use "this.propertyName" to assign your public properties and methods, and finally use "return this" at the end? This way seems much simpler to me, as you can create private properties and methods with the usual "var" or "function" syntax, or use the "this.propertyName" syntax to declare your public methods. Here's the method I'm suggesting: (function() { var privateMethod = function () { alert('This is a private method.'); } this.publicMethod = function () { alert('This is a public method.'); } return this; })(); Are there any pros/cons to using the method above? What about the others?

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• How to hire a good ui designer

  - by Mark

  I have a webapp that can probably look better. Looking on jobs.stackoverflow, all I see for UI jobs are full-time positions. Is it possible to hire a good UI designer for freelance work? Where would I begin? And anyone know how much I would be looking at?

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• How to use a 3rd party control inside the viewmodel?

  - by Sander

  I have a 3rd party control which among other things performs loading of some data. I want my viewmodel to keep track of this load operation and adjust its own state accordingly. If it were up to me, I'd do the data loading far away from the view, but it is not. So, I seem to be in the situation where my viewmodel depends on my view. How do I best handle this? I feel rather dirty making the view publish events to the viewmodel but I don't see any other reasonable way to get this info into the viewmodel. A similar situation might crop up with standard controls, too - imagine if your viewmodel depends on the events coming from a MediaElement - how do you properly model this? Do you put the MediaElement into the viewmodel? That doesn't sound right. If publishing the events to the viewmodel is indeed the most reasonable way, is there some common pattern used for this? How do you do it?

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• Book for a Windows Application

  - by cateof

  Hello everybody. I want to create an small GUI Windows application that looks like all the other usual appz. I am searching for a book that describes the whole procedure. Let's say an address book application that can be have a small database, minimized in the task bar, doing things in the background and so on. I don't care for the language. But I would prefer to do it in .NET C++. I know it is a "very" general question, so Thanks in advance.

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• How to maintain a pool of names ?

  - by Jacques René Mesrine

  I need to maintain a list of userids (proxy accounts) which will be dished out to multithreaded clients. Basically the clients will use the userids to perform actions; but for this question, it is not important what these actions are. When a client gets hold of a userid, it is not available to other clients until the action is completed. I'm trying to think of a concurrent data structure to maintain this pool of userids. Any ideas ? Would a ConcurrentQueue do the job ? Clients will dequeue a userid, and add back the userid when they are finished with it.

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• Android 2.1 address bar causes change in viewport dimensions

  - by davehumyo

  Hi, I have a page that has a 100% width and height div in it (all surrounding elements are sized accordingly so that it does actually achieve 100% width and height). Below that div I have a second div with a fixed height. In mobile safari and blackberry everything is fine, when the page loads the dimensions are applied correctly (the top div filling the viewport) and the user can scroll down to reveal the second div. Android 2.1 also applies the dimensions correctly, but with an added quirk; when the user scrolls down and removes the address bar from the page, the dimensions of the div are recalculated to fill the viewport, causing the content to jump. Ideally I would like the dimensions of the div to remain static when the page is scrolled, but remain 100% so that it will fill the viewport regardless of device size or orientation. Does anyone know of any way to disable this recalculation? Thanks for any help you can provide.

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• Why does C# allow abstract class with no abstract members?

  - by fatcat1111

  The C# spec, section 10.1.1.1, states: An abstract class is permitted (but not required) to contain abstract members. This allows me to create classes like this: public abstract class A { public void Main() { // it's full of logic! } } This is really a concrete class; it's only abstract in so far as one can't instantiate it. If inheritors don't actually have to provide implementation, then why call it abstract?

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• Visitor Pattern can be replaced with Callback functions?

  - by getit

  Is there any significant benefit to using either technique? In case there are variations, the Visitor Pattern I mean is this: http://en.wikipedia.org/wiki/Visitor_pattern And below is an example of using a delegate to achieve the same effect (at least I think it is the same) Say there is a collection of nested elements: Schools contain Departments which contain Students Instead of using the Visitor pattern to perform something on each collection item, why not use a simple callback (Action delegate in C#) Say something like this class Department { List Students; } class School { List Departments; VisitStudents(Action<Student> actionDelegate) { foreach(var dep in this.Departments) { foreach(var stu in dep.Students) { actionDelegate(stu); } } } } School A = new School(); ...//populate collections A.Visit((student)=> { ...Do Something with student... }); *EDIT Example with delegate accepting multiple params Say I wanted to pass both the student and department, I could modify the Action definition like so: Action class School { List Departments; VisitStudents(Action<Student, Department> actionDelegate, Action<Department> d2) { foreach(var dep in this.Departments) { d2(dep); //This performs a different process. //Using Visitor pattern would avoid having to keep adding new delegates. //This looks like the main benefit so far foreach(var stu in dep.Students) { actionDelegate(stu, dep); } } } }

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• Configuration and Model-View

  - by HH

  I am using the Model-View pattern on a small application I'm writing. Here's the scenario: The model maintains a list of directories from where it can extract the data that it needs. The View has a Configuration or a Setting dialog where the user can modify this list of directories (the dialog has a JList displaying the list in addition to add and remove buttons). I need some advice from the community: The View needs to communicate these changes to the model. I thought first of adding to the model these methods: addDirectory() and removeDirectory(). But I am trying to limit the number of methods (or channels) that the View can use to communicate with and manipulate the model. Is there any good practice for this? Thank you.

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• What makes an effective UI for displaying versioning of structured hierarchical data

  - by Fadrian Sudaman

  Traditional version control system are displaying versioning information by grouping Projects-Folders-Files with Tree view on the left and details view on the right, then you will click on each item to look at revision history for that configuration history. Assuming that I have all the historical versioning information available for a project from Object-oriented model perspective (e.g. classes - methods - parameters and etc), what do you think will be the most effective way to present such information in UI so that you can easily navigate and access the snapshot view of the project and also the historical versioning information? Put yourself in the position that you are using a tool like this everyday in your job like you are currently using SVN, SS, Perforce or any VCS system, what will contribute to the usability, productivity and effectiveness of the tool. I personally find the classical way for display folders and files like above are very restrictive and less effective for displaying deep nested logical models. Assuming that this is a greenfield project and not restricted by specific technology, how do you think I should best approach this? I am looking for idea and input here to add values to my research project. Feel free to make any suggestions that you think is valuable. Thanks again for anyone that shares their thoughts.

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• Learning to think in the Object Oriented Way

  - by SpikETidE

  Hi Everyone.... I am a programmer trying to learn to code in the object oriented paradigm... I mainly work with PHP and i thought of learning the zend framework... So, felt I need to learn to code in OO PHP.... The problem is, having done code using functions for quite a long time, i just can't get my head to think in the OO way.... Also felt that probably I am not the only one facing this problem since the beginning of time... So, how did you people learn object oriented programming... especially how did you succeed in "unlearning" to code using functions... and learn to see you code as objects...? Is there any good resource books or sites where one could find help...?? Thanks for sharing your knowledge and experiences...

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• Should Factories Persist Entities?

  - by mxmissile

  Should factories persist entities they build? Or is that the job of the caller? Pseudo Example Incoming: public class OrderFactory { public Order Build() { var order = new Order(); .... return order; } } public class OrderController : Controller { public OrderController(IRepository repository) { this.repository = repository; } public ActionResult MyAction() { var order = factory.Build(); repository.Insert(order); ... } } or public class OrderFactory { public OrderFactory(IRepository repository) { this.repository = repository; } public Order Build() { var order = new Order(); ... repository.Insert(order); return order; } } public class OrderController : Controller { public ActionResult MyAction() { var order = factory.Build(); ... } } Is there a recommended practice here?

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• Which fieldtype is best for storing PRICE values?

  - by BerggreenDK

  Hi there I am wondering whats the best "price field" in MSSQL for a shoplike structure? Looking at this overview: http://www.teratrax.com/sql_guide/data_types/sql_server_data_types.html We have datatypes called money, smallmoney, then we have decimal/numeric and lastly float and real Name, memory/disk-usage and value ranges: Money: 8 bytes (values: -922,337,203,685,477.5808 to +922,337,203,685,477.5807) Smallmoney: 4 bytes (values: -214,748.3648 to +214,748.3647) Decimal: 9 [default, min. 5] bytes (values: -10^38 +1 to 10^38 -1 ) Float: 8 bytes (values: -1.79E+308 to 1.79E+308 ) Real: 4 bytes (values: -3.40E+38 to 3.40E+38 ) My question is: is it really wise to store pricevalues in those types? what about eg. INT? Int: 4 bytes (values: -2,147,483,648 to 2,147,483,647) Lets say a shop uses dollars, they have cents, but I dont see prices being $49.2142342 so the use of a lot of decimals showing cents seems waste of SQL bandwidth. Secondly, most shops wouldn't show any prices near 200.000.000 (not in normal webshops at least... unless someone is trying to sell me a famous tower in Paris) So why not go for an int? An int is fast, its only 4 bytes and you can easily make decimals, by saving values in cents instead of dollars and then divide when you present the values. The other approach would be to use smallmoney which is 4 bytes too, but this will require the math part of the CPU to do the calc, where as Int is integer power... on the downside you will need to divide every single outcome. Are there any "currency" related problems with regionalsettings when using smallmoney/money fields? what will these transfer too in C#/.NET ? Any pros/cons? Go for integer prices or smallmoney or some other? Whats does your experience tell?

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• How to use Unique Composite Key

  - by LifeH2O

  I have a table Item(ItemName*, ItemSize*, Price, Notes) I was making composite key of (ItemName,ItemSize) to uniquely identify item. And now after reading some answers on stackoverflow suggesting the use of UNIQUE i revised it as Item(ItemID*, ItemName, ItemSize, Price, Notes) But How to apply UNIQUE constraint on ItemName and ItemSize please correct if there is something wrong in question

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• How to export data which are mapped to enumerations

  - by Joshua

  I have a set of data which needs to be imported from a excel sheet, lets take the simplest example. Note: the data might eventually support uploading any locale. e.g. assuming one of the fields denoting a user is gender mapped to an enumeration and stored in the database as 0 for male and 1 for female. 0 and 1 being short values. If I have to import the values I cannot expect the user to punch in numbers (since they are not intuitive and is cumbersome when the enumerations are bigger), what would be the correct way to map to enumerations. Should we ask them to provide a string value in these cases (e.g. male or female) and provide the transformation to a enum in our code by wring a method public static Gender Gender.fromString(String value)

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• Proper abstraction of the database tier in a 3 tier system?

  - by Earlz

  Hello, I am creating a 3 tier application. Basically it goes Client - (through optional server to be a thin-client) - Business Logic - Database Layer And basically making it so that there is never any skipping around. As such, I want for all of the SQL queries and such to be in the Database Layer. Well, now I'm a bit confused. I made a few static classes to start off the database tier but what should I do for the database connections? Should I just create a new database connection anytime I enter the Database Layer or would that be wasteful? Does Connection.Open() take time whenever you have a ConnectionPool? To me, it just feels wrong for the Business tier to have to pass in a IdbConnection object to the Database tier. It seems like the Database tier should handle all of that DB-specific code. What do you think? How can I do it the proper way while staying practical?

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• Best practice to modularise a large Grails app?

  - by Mulone

  Hi all, A Grails app I'm working on is becoming pretty big, and it would be good to refactor it into several modules, so that we don't have to redeploy the whole thing every time. In your opinion, what is the best practice to split a Grails app in several modules? In particular I'd like to create a package of domain classes + relevant services and use it in the app as a module. Is this possible? Is it possible to do it with plugins? Cheers, Mulone

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• Are we using IoC effectively?

  - by Juliet

  So my company uses Castle Windsor IoC container, but in a way that feels "off": All the data types are registered in code, not the config file. All data types are hard-coded to use one interface implementation. In fact, for nearly all given interfaces, there is and will only ever be one implementation. All registered data types have a default constructor, so Windsor doesn't instantiate an object graph for any registered types. The people who designed the system insist the IoC container makes the system better. We have 1200+ public classes, so its a big system, the kind where you'd expect to find a framework like Windsor. But I'm still skeptical. Is my company using IoC effectively? Is there an advantage to new'ing objects with Windsor than new'ing objects with the new keyword?

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• What should go in each MVVM triad?

  - by Harry

  OK, let's say I am creating a program that will list users contacts in a ListBox on the left side of the screen. When a user clicks on the contact, a bunch of messages or whatever appears in the main part of the window. Now my question is: how should the MVVM triads look? I have two models: Contact, and Message. The Contact model contains a list of Message models. Each ViewModel object will contain a single corresponding Model, right? And what about the Views? I have a "MainView" that is the main window, that will have things like the menu, toolbar etc. Do I put the ListBox in the MainView? My confusion is with what to put where; for example, what should the ContactView contain? Just a single instance of a contact? So the DataTemplate, ControlTemplate, context menus, styles etc for that single contact, and then just have a ListBox of them in the MainView...? Thanks.

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• Should I create subclass NSManagedObject or not?

  - by TP

  Hi, I have spent a few days learning and writing NSCoding and finally got it working. However, it took very long to archive and unarchive the (quite complex) object graph, which is unacceptable. After searching the internet for some time, I think the better way is to use core data. Do you recommend that 1) I should rewrite all my classes as subclasses of NSManagedObject or 2) should I create an instance variable of NSManagedObject in each of my class so that any changes to the class also updates its core data representation? Doing either way will need significant changes to the exiting classes and I think I have to update lots of unit test cases as well if it changes the way the classes are initialized. What do you recommend? I really don't want to head to the wrong approach again... Thanks!

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• Alternatives to checking against the system time

  - by vikp

  Hi, I have an application which license should expire after some period of time. I can check the time in the applicatino against the system time, but system time can be changed by the administrator, therefore it's not a good idea to check against the system time in my opinion. What alternatives do I have? Thank you

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• Best datastructure for frequently queried list of objects

  - by panzerschreck

  Hello, I have a list of objects say, List. The Entity class has an equals method,on few attributes ( business rule ) to differentiate one Entity object from the other. The task that we usually carry out on this list is to remove all the duplicates something like this : List<Entity> noDuplicates = new ArrayList<Entity>(); for(Entity entity: lstEntities) { int indexOf = noDuplicates.indexOf(entity); if(indexOf >= 0 ) { noDuplicates.get(indexOf).merge(entity); } else { noDuplicates.add(entity); } } Now, the problem that I have been observing is that this part of the code, is slowing down considerably as soon as the list has objects more than 10000.I understand arraylist is doing a o(N) search. Is there a faster alternative, using HashMap is not an option, because the entity's uniqueness is built upon 4 of its attributes together, it would be tedious to put in the key itself into the map ? will sorted set help in faster querying ? Thanks

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• Are today's young programmers getting wrapped around the axle with patterns and practices?

  - by Robert Harvey

  Recently I have noticed a number of questions on SO that look something like this: I am writing a small program to keep a list of the songs that I keep on my ipod. I'm thinking about writing it as a 3-tier MVC Ruby on Rails web application with TDD, DDD and IOC, using a factory pattern to create the classes and a singleton to store my application settings. Do you think I'm taking the right approach? Do you think that we're handing novice programmers a very sharp knife and telling them, "Don't cut yourself with this"? NOTE: Despite the humorous tone, this is a serious (and programming-related) question.

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• What is the minimum screen resolution for which you guys currently optimize your web designs?

  - by Hermet

  I don't really know if I'm asking in the right place, so if my question has to be transferred I apologize for it. I am totally noob in this place. Thank you.

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