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  • In a star schema, are foreign key constraints between facts and dimensions neccessary?

    - by Garett
    I'm getting my first exposure to data warehousing, and I’m wondering is it necessary to have foreign key constraints between facts and dimensions. Are there any major downsides for not having them? I’m currently working with a relational star schema. In traditional applications I’m used to having them, but I started to wonder if they were needed in this case. I’m currently working in a SQL Server 2005 environment.

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  • Cocoa framework development: sharing between projects

    - by e.James
    I am currently developing a handful of similar Cocoa desktop apps. In an effort to share code between them, I have identified a set of core classes and functions that can be common across all of these applications. I would like to bundle this common code into a framework which all of my current applications (and any future ones) can link against. Now, here's the hard part: I'm going to be developing this framework as I go, so I need each of my desktop apps to have a reference to it, but I want to be able to edit the framework source code from within each of the app projects and have the framework automatically rebuilt as required. For example, let's say I have the Xcode project for DesktopAppNumberOne open, and I decide that one of my framework classes needs to be changed. I would like to: Open and edit the source file for that framework class without having to open the framework project in Xcode. Hit "build" on DesktopAppNumberOne, and see the framework rebuilt first (because one of its sources has changed), then see parts of DesktopAppNumberOne rebuilt (because one of the frameworks it links against has changed). I can see how to do this with only one app and one framework, but I'm having trouble figuring out how to do it with multiple apps that share a single framework. Has anyone had success with this approach? Am I perhaps going about this the wrong way? Any help would be appreciated.

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  • C++. How to define template parameter of type T for class A when class T needs a type A template parameter?

    - by jaybny
    Executor class has template of type P and it takes a P object in constructor. Algo class has a template E and also has a static variable of type E. Processor class has template T and a collection of Ts. Question how can I define Executor< Processor<Algo> > and Algo<Executor> ? Is this possible? I see no way to defining this, its kind of an "infinite recursive template argument" See code. template <class T> class Processor { map<string,T> ts; void Process(string str, int i) { ts[str].Do(i); } } template <class P> class Executor { Proc &p; Executor(P &p) : Proc(p) {} void Foo(string str, int i) { p.Process(str,i); } Execute(string str) { } } template <class E> class Algo { static E e; void Do(int i) {} void Foo() { e.Execute("xxx"); } } main () { typedef Processor<Algo> PALGO; // invalid typedef Executor<PALGO> EPALGO; typedef Algo<EPALGO> AEPALGO; Executor<PALGO> executor(PALGO()); AEPALGO::E = executor; }

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  • Handling Dialogs in WPF with MVVM

    - by Ray Booysen
    In the MVVM pattern for WPF, handling dialogs is one of the more complex operations. As your view model does not know anything about the view, dialog communication can be interesting. I can expose an ICommand that when the view invokes it, a dialog can appear. Does anyone know of a good way to handle results from dialogs? I am speaking about windows dialogs such as MessageBox. One of the ways we did this was have an event on the viewmodel that the view would subscribe to when a dialog was required. public event EventHandler<MyDeleteArgs> RequiresDeleteDialog; This is OK, but it means that the view requires code which is something I would like to stay away from.

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  • WPF buttons same/recommended width

    - by rwallace
    Suppose you have a window with multiple buttons such as Ok/Cancel or Yes/No/Cancel. All the buttons need to be the same width. Obviously this could be done by just guessing a number and hardwiring all of them to that number. Is there a better way to do it, one that would take into account preferred/recommended sizes (just how wide should an Ok button be anyway? This is not a rhetorical question, I actually don't know the answer!), what's needed by the text of the longest caption, what happens if the font size is increased etc?

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  • Building a wiki like data model in rails question.

    - by lillq
    I have a data model in which I would like to have an item that has a description that can be edited. I would like to also keep track of all edits to the item. I am running into issues with my current strategy, which is: class Item < ActiveRecord::Base has_one :current_edit, :class_name => "Edit", :foreign_key => "current_edit_id" has_many :edits end class Edit < ActiveRecord::Base belongs_to :item end Can the Item have multiple associations to the same class like this? I was thinking that I should switch to keeping track of the edit version in the Edit object and then just sorting the has_many relationship base on this version.

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  • Passing an array for setting variable

    - by mathk
    Hi, I often see this idiom when reading php code: public function __construct($config) { if (array_key_exists('options', $config)) { ... } if (array_key_exists('driver_options', $config)) { ... } } Here I am concern with the way the parameter is used. If I were in lisp I would do: (defun ct (&key options driver_options) (do-something-with-option-and-driver_option)) But since I am in PHP I would rather have a constructor that take a list of parameter and let them be null if there a not require. So what do you guys think about having an array as parameter in other to do some initialization-or-whatever? In other to answer you have to take in account the point of view of the user of the function and the designer of the API. Also have you ever heard this has a code-smell? thanks

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  • Patterns for wrapping a command line tool in another language

    - by Tom Duckering
    I'm currently writing some Java to wrap around an extensive command line tool. It feels like I'm writing a lot of similar code. I'm wondering if there are any established patterns for wrapping command line tools - passing arguments and handling output and so on. Specific examples in Java would obviously be great, but any general suggestions or pointers are welcome too.

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  • How to make some functions of a class as private for third level of inheritance.

    - by Shantanu Gupta
    I have created a class say A which has some functions defined as protected. Now Class B inherits A and class C inherits B. Class A has private default constructor and protected parameterized constructor. I want Class B to be able to access all the protected functions defined in Class A but class C can have access on some of the functions only not all the functions and class C is inheriting class B. How can I restrict access to some of the functions of Class A from Class C ? Class A { private A(){} protected A(int ){} protected calc(){} protected allow(){} } Class B : A {} // calc() and allow() should be accessible here CLass C:B { // calc() should not be accessible here but allow() should be accessible here. }

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  • Managing important runtime business logic with regard to a codebase

    - by Daniel Beardsley
    I'm working on a project which will end up have a lot of application information stored in the form of records in a database. In this case, it's the configuration of data views: which grid columns to show/hide default filters to apply to each grid view column titles sorting subtotaling ... This information is a big part of the value of the application and is essential to it's function. The data will be altered by admins a fair amount, so it's not static and it wouldn't be appropriate to have to deploy a new version of the app every time the data changes. The question is, Where should this data be stored? It will definitely live in the database because that's how it's accessed, but I feel like it needs to also be kept with the version controlled codebase because it's an integral part of functioning of the application. Has anyone dealt with an issue like this before? What did you end up doing?

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  • MyController class must produce class according to the enum type.

    - by programmerist
    GenoTipController must produce class according to the enum type. i have 3 class: _Company,_Muayene,_Radyoloji. Also i have CompanyView Class GetPersonel method. if you look GenoTipController my codes need refactoring. Can you understand me? i need a class according to ewnum type must me produce class. For example; case DataModelType.Radyoloji it must return radyoloji= new Radyoloji . Everything must be one switch case? public class GenoTipController { public _Company GenerateCompany(DataModelType modeltype) { _Company company = null; switch (modeltype) { case DataModelType.Radyoloji: break; case DataModelType.Satis: break; case DataModelType.Muayene: break; case DataModelType.Company: company = new Company(); break; default: break; } return company; } public _Muayene GenerateMuayene(DataModelType modeltype) { _Muayene muayene = null; switch (modeltype) { case DataModelType.Radyoloji: break; case DataModelType.Satis: break; case DataModelType.Muayene: muayene = new Muayene(); break; case DataModelType.Company: break; default: break; } return muayene; } public _Radyoloji GenerateRadyoloji(DataModelType modeltype) { _Radyoloji radyoloji = null; switch (modeltype) { case DataModelType.Radyoloji: radyoloji = new Radyoloji(); break; case DataModelType.Satis: break; case DataModelType.Muayene: break; case DataModelType.Company: break; default: break; } return radyoloji; } } public class CompanyView { public static List GetPersonel() { GenoTipController controller = new GenoTipController(); _Company company = controller.GenerateCompany(DataModelType.Company); return company.GetPersonel(); } } public enum DataModelType { Radyoloji, Satis, Muayene, Company } }

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  • PHP Frontpage/Page controller

    - by atno
    I using the following as Frontpage/Page Controller(s) and it's working ok so far, except two problems I'm facing which as you can see are the $pages array and the switch, which are actually much much longer as the one I've pasted here. Everytime there is a need for a new page controller I have to add it to $pages array and to switch which makes that list very long. How would you overcome this problem and do you see any other improvement on this code? loadLogic() in page controllers it is used to get functions under pages/controllername/logic/function.php. Frontpage Controller - index.php: include 'common/common.php'; if(!isset($_GET['p']) OR $_GET['p'] == ''){ $_GET['p'] = 'home'; header('Location: index.php?p=home'); } $pages = array('home','register','login','logout','page1','page2','page3'); $_GET['p'] = trim($_GET['p']); if(isset($_GET['p'])){ if(in_array($_GET['p'], $pages)){ switch ($_GET['p']) { case 'home': include 'home.php'; break; case 'register': include 'register.php'; break; case 'login': include 'login.php'; break; case 'logout': include 'logout.php'; break; case 'page1': include 'page1.php'; break; case 'page2': include 'page2.php'; break; case 'page3': include 'page3.php'; break; } }else{ echo '404!'; } } Page Controller - {home,register,login,logout,page1,page2,page3}.php: include 'tpl/common/header.php'; contentStart(); if(isset($_SESSION['logged'])){ loadLogic('dashboard'); }else{ loadLogic('nologin'); } //Display login form in logic page instead links // if(!isset($_SESSION['logged'])){ contentEnd(); loadLogic('nologinForm'); }else{ contentEnd(); include'tpl/common/rcol.php'; } include 'tpl/common/footer.php'; function loadLogic(): function loadLogic($logic) { $path = dirname(__DIR__) . '/pages'; $controller = preg_split('/&/',$_SERVER['QUERY_STRING']); $controller = trim($controller[0],"p="); $logicPath = 'logic'; $logic = $logic . '.php'; $err = 0; $logicFullPath = $path.'/'.$controller.'/'.$logicPath.'/'.$logic; if($err == '0'){ include "$logicFullPath"; } } Folder Structure: projectName | ---> common | ---> pages | | | --->home | | | --->register | | | --->login | | | --->logout | | | --->page1 | | | --->page2 | | | --->page3 | ---> tpl | | | ---> common | --> home.php | --> register.php | --> login.php | --> logout.php | --> page1.php | --> page2.php | --> page3.php

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  • internal implementation of database Queries

    - by harigm
    In my experience I have used many queries like select, order by, where clause etc.. in mysql, sql-server, oracle etc For a moment i have thought, 1)how is this internally written to implement the above queries 2) which language do they use? 3) is that programming language? if yes which language? 4)what kind of environment required to implement this kind of complex database

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  • Entity framework and database logic.

    - by Xavier Devian
    Hi all, i have a question that's being around for several years. As all you know entity framework is an ORM tool that tries to model the database to an object oriented access model. All the samples I've seen are quering directly to the database tables. So, which is the role of the views in the database now?. The views were used to model the database in a more friendly way, that is, several physical tables, one logic table. This was great for example in hidding the complex relational model on stored procedures as queryng the views inside them was much easier than reproducing the query joins over and over on each stored procedure. So the question is, why is entity framework so good if stored procedures can not take benefit of it?

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  • To join or not to join - database structure

    - by Industrial
    Hi! We're drawing up the database structure with the help of mySQL Workbench for a new app and the number of joins required to make a listing of the data is increasing drastically as the many-to-many relationships increases. The questions: Is it really that bad to merge tables where needed and thereby reducing joins? Is there a better way then pivot tables to take care of many-to-many relationships? We discussed about instead storing all data in serialized text columns and having the application make the sorting instead of the database, but this seems like a very bad idea, even though that the database will be heavily cached. What do you think? Thanks!

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  • Spring 2.0.0/2.0.6 to 3.0.5 migration stories

    - by Pangea
    We are in the process of migrating to 3.0.5 of spring from 2.0.x. We mainly use spring in below scenarios custom scope: thread local scope persistence: jdbc+hibernate 3.6 (but moving to mix of ejb 3.0+jpa 2.0+hibernate, not sure if all 3 can co-exist in 1 app) transactions: local (but planning to use jta due to the necessity of using multiple persistence inits, and has to use ejb+jpa+hibernate in 1 single trans), declarative trans mgmt parent-child contexts cxf annotations+xml OracleLobHandler Resource/ResourceBundleMessageResource JSF/Facelets with FacesSpringVariableResolver ActiveMQ integration Quartz integration TaskExecutor JMX exporter HttpExporter/Invoker Appreciate if someone can share their experiences like what to watch out for head aches/pain points which ones to drop for better alternate choices in new 3.0.5 release Is it better to switch from commons/iscreen validator to Hibernate Validator (Spec impl) or Spring Validator Is there a bean mapping framework in spring that i can use instead of Dozer XSLT transformation helper: currently we have small homegrown framework to cache xslts during load. if spring can do that for me then I would like to drop this Encryption/Decryption support. Password generation support. Authentication with SALT any SAML (or claims based secur New ideas Suggestions Switch to latest version of aspectj Upgrade guide from 2.5 to 3.0.5

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  • Is there any danger in committing to a component library such as SmartGwt or Swing?

    - by Banang
    Since February this year I have been working on an app that's built using SmartGWT components. Generally, I find the components very nice to work with, and the fact that they're open source and free to use is just fantastic. However, I can't seem to shake the feeling that it's not a durable way of developing, but I can't quite explain why. Maybe it's because I know that any minute now the team developing it could decide to stop, which would leave me and my team in a bit of a pickle, but I'm sure there must be something more. I have been trying to find ways of explaining this feeling to myself, but to no avail. Therefore I turn to you, dear community, to ask if you can come up with a good reason why committing to building your app (that's supposed to be around for many more years to come) using a component library such as SmartGWT is a bad idea? Is there any reason I should just have developed the components myself? Or did I make the right choice when deciding not to reinvent the wheel and just go for what was readily available?

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  • How do I call functions of an object inside the same object?

    - by Roly
    I have the following Javascript code add_num = { f: function(html, num) { alert(this.page); }, page : function() { return parseInt(this.gup('page')); }, gup : function(name) { name = name.replace(/[\[]/,'\\\[').replace(/[\]]/,'\\\]'); var regex = new RegExp('[\\?&]'+name+'=([^&#]*)'); var results = regex.exec(window.location.href); if(results == null) return ''; else return results[1]; } } But when I call add_num.f() what I get from alert() is the actual code of page. That is, it returns function() { return parseInt(this.gup('page')); } I was expecting a numeric value and not any code at all.

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  • Designing software interface for various screen sizes

    - by Tower
    Hi, Nowadays we have screens like 1920x1200 and 1680x1050 in popular use and some even use 2560x1600 resolution while some older systems still rely on a 800x600 resolution. I am writing a software that looks good on a 1680x1050, but too small on a 1920x1200 and too large on a 1024x768. Do you have suggestions how to go for designing an application for various screen sizes? Things were a lot simpler before when we had little differences in resolutions, but now it seems there's no good way of handling this. I know this question is more about designing / layout than programming, but I bet this is more or less part of programmers life so I made this post here.

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  • Event feed implementation - will it scale?

    - by SlappyTheFish
    Situation: I am currently designing a feed system for a social website whereby each user has a feed of their friends' activities. I have two possible methods how to generate the feeds and I would like to ask which is best in terms of ability to scale. Events from all users are collected in one central database table, event_log. Users are paired as friends in the table friends. The RDBMS we are using is MySQL. Standard method: When a user requests their feed page, the system generates the feed by inner joining event_log with friends. The result is then cached and set to timeout after 5 minutes. Scaling is achieved by varying this timeout. Hypothesised method: A task runs in the background and for each new, unprocessed item in event_log, it creates entries in the database table user_feed pairing that event with all of the users who are friends with the user who initiated the event. One table row pairs one event with one user. The problems with the standard method are well known – what if a lot of people's caches expire at the same time? The solution also does not scale well – the brief is for feeds to update as close to real-time as possible The hypothesised solution in my eyes seems much better; all processing is done offline so no user waits for a page to generate and there are no joins so database tables can be sharded across physical machines. However, if a user has 100,000 friends and creates 20 events in one session, then that results in inserting 2,000,000 rows into the database. Question: The question boils down to two points: Is this worst-case scenario mentioned above problematic, i.e. does table size have an impact on MySQL performance and are there any issues with this mass inserting of data for each event? Is there anything else I have missed?

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  • What should I do if i have a factory method which requires different parameters for different implem

    - by Sam Holder
    I have an interface, IMessage and a class which have several methods for creating different types of message like so: class MessageService { IMessage TypeAMessage(param 1, param 2) IMessage TypeBMessage(param 1, param 2, param 3, param 4) IMessage TypeCMessage(param 1, param 2, param 3) IMessage TypeDMessage(param 1) } I don't want this class to do all the work for creating these messages so it simply delegates to a MessageCreatorFactory which produces an IMessageCreator depending on the type given (an enumeration based on the type of the message TypeA, TypeB, TypeC etc) interface IMessageCreator { IMessage Create(MessageParams params); } So I have 4 implementations of IMessageCreator: TypeAMessageCreator, TypeBMessageCreator, TypeCMessageCreator, TypeDMessageCreator I ok with this except for the fact that because each type requires different parameters I have had to create a MessageParams object which contains 4 properties for the 4 different params, but only some of them are used in each IMessageCreator. Is there an alternative to this? One other thought I had was to have a param array as the parameter in the Create emthod, but this seems even worse as you don't have any idea what the params are. Or to create several overloads of Create in the interface and have some of them throw an exception if they are not suitable for that particular implementation (ie you called a method which needs more params, so you should have called one of the other overloads.) Does this seem ok? Is there a better solution?

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  • Why does C++ mandate that complex only be instantiated for float, double, or long double?

    - by templatetypedef
    According to the C++ ISO spec, §26.2/2: The effect of instantiating the template complex for any type other than float, double or long double is unspecified. Why would the standard authors explicitly add this restriction? This makes it unspecified, for example, what happens if you make complex<int> or a complex<MyCustomFixedPointType> and seems like an artificial restriction. Is there a reason for this limitation? Is there a workaround if you want to instantiate complex with your own custom type? I'm primarily asking this question because of this earlier question, in which the OP was confused as to why abs was giving bizarre outputs for complex<int>. That said, this still doesn't quite make sense given that we also might want to make complex numbers out of fixed-points types, higher-precision real numbers, etc. Thanks!

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