Search Results

Search found 8692 results on 348 pages for 'patterns practices'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 162/348 | < Previous Page | 158 159 160 161 162 163 164 165 166 167 168 169  | Next Page >

  • database design - empty fields

    - by imanc
    Hey, I am currently debating an issue with a guy on my dev team. He believes that empty fields are bad news. For instance, if we have a customer details table that stores data for customers from different countries, and each country has a slightly different address configuration - plus 1-2 extra fields, e.g. French customer details may also store details for entry code, and floor/level plus title fields (madamme, etc.). South Africa would have a security number. And so on. Given that we're talking about minor variances my idea is to put all of the fields into the table and use what is needed on each form. My colleague believes we should have a separate table with extra data. E.g. customer_info_fr. But this seams to totally defeat the purpose of a combined table in the first place. His argument is that empty fields / columns is bad - but I'm struggling to find justification in terms of database design principles for or against this argument and preferred solutions. Another option is a separate mini EAV table that stores extra data with parent_id, key, val fields. Or to serialise extra data into an extra_data column in the main customer_data table. I think I am confused because what I'm discussing is not covered by 3NF which is what I would typically use as a reference for how to structure data. So my question specifically: - if you have slight variances in data for each record (1-2 different fields for instance) what is the best way to proceed?

    Read the article

  • What is the best practice for accessing Model using MVVM pattern

    - by Dzenand
    I have a database that communicates with webservices with my Model (own thread) and exposes Data Objects. My UI application consists of different Views and ViewModels and Custom Controls. I'm using ServiceProvider (IServiceProvider) to access the Model and route the events to the UI thread. Communication between the ViewModels is handeled by a Messenger. Is this way to go? I was also wondering what is the best way to strucutre the DataObjects At the moment i have the DataObjects that have a hierarchy structure but does not support INotifyProperty though the children list are of type of ObservableCollection. I have no possiblity to implement notifypropertychange on the properties. I was wondering the best way of making them MVVM friendly. Implementing a partial class and adding all the properties or commands that are necessary or wrapping all the DataObjects and keep the Model list and MVVM list in sync. All thoughts and ideas are appreciated.

    Read the article

  • how should i create my own 'now' / DateTime.Now ?

    - by Michel
    Hi all, i'm starting to build a part of a system which will hold a lot of DateTime validations, and a lot of 'if it was done before now' or 'if it will start in an hour etc'. Usual way to go is to use DateTime.Now to get the actual time. I predict however, that during unit test that will give me a real headache because i will have to setup my testdata for the time when the test will run in stead of use a default set of test data. So i thought: why not use my own 'now' so i can set the current datetime to any moment in time. As i don't want to set the testservers internal clock i was thinking about this solution, and i was wondering what you think of it. Base thought is that i use my own DateTime class. That class gives you the current datetime, but you can also set your own time from outside. public static class MyDateTime { private static TimeSpan _TimeDifference = TimeSpan.Zero; public static DateTime Now { get { return DateTime.Now + _TimeDifference; } } public static void SetNewNow(DateTime newNow) { _TimeDifference = newNow - DateTime.Now; } public static void AddToRealTime(TimeSpan timeSpan ) { _TimeDifference = timeSpan; } public static void SubtractFromRealTime(TimeSpan timeSpan) { _TimeDifference = - timeSpan; } }

    Read the article

  • C# MultiThread Safe Class Design

    - by Robert
    I'm trying to designing a class and I'm having issues with accessing some of the nested fields and I have some concerns with how multithread safe the whole design is. I would like to know if anyone has a better idea of how this should be designed or if any changes that should be made? using System; using System.Collections; namespace SystemClass { public class Program { static void Main(string[] args) { System system = new System(); //Seems like an awkward way to access all the members dynamic deviceInstance = (((DeviceType)((DeviceGroup)system.deviceGroups[0]).deviceTypes[0]).deviceInstances[0]); Boolean checkLocked = deviceInstance.locked; //Seems like this method for accessing fields might have problems with multithreading foreach (DeviceGroup dg in system.deviceGroups) { foreach (DeviceType dt in dg.deviceTypes) { foreach (dynamic di in dt.deviceInstances) { checkLocked = di.locked; } } } } } public class System { public ArrayList deviceGroups = new ArrayList(); public System() { //API called to get names of all the DeviceGroups deviceGroups.Add(new DeviceGroup("Motherboard")); } } public class DeviceGroup { public ArrayList deviceTypes = new ArrayList(); public DeviceGroup() {} public DeviceGroup(string deviceGroupName) { //API called to get names of all the Devicetypes deviceTypes.Add(new DeviceType("Keyboard")); deviceTypes.Add(new DeviceType("Mouse")); } } public class DeviceType { public ArrayList deviceInstances = new ArrayList(); public bool deviceConnected; public DeviceType() {} public DeviceType(string DeviceType) { //API called to get hardwareIDs of all the device instances deviceInstances.Add(new Mouse("0001")); deviceInstances.Add(new Keyboard("0003")); deviceInstances.Add(new Keyboard("0004")); //Start thread CheckConnection that updates deviceConnected periodically } public void CheckConnection() { //API call to check connection and returns true this.deviceConnected = true; } } public class Keyboard { public string hardwareAddress; public bool keypress; public bool deviceConnected; public Keyboard() {} public Keyboard(string hardwareAddress) { this.hardwareAddress = hardwareAddress; //Start thread to update deviceConnected periodically } public void CheckKeyPress() { //if API returns true this.keypress = true; } } public class Mouse { public string hardwareAddress; public bool click; public Mouse() {} public Mouse(string hardwareAddress) { this.hardwareAddress = hardwareAddress; } public void CheckClick() { //if API returns true this.click = true; } } }

    Read the article

  • Have you ever derived a programming solution from nature?

    - by Ryu
    When you step back and look at ... the nature of animals, insects, plants and the problems they have organically solved perhaps even the nature and balance of the universe Have you ever been able to solve a problem by deriving an approach from nature? I've heard of Ant Colony Algorithms being able to optimize supply chain amongst other things. Also Fractal's being the "geometry of nature" have been applied to a wide range of problems. Now that spring is here again and the world is coming back to life I'm wondering if anybody has some experiences they can share. Thanks PS I would recommend watching the "Hunting the Hidden Dimension" Nova episode on fractals.

    Read the article

  • Best ways to reuse Java methods

    - by carillonator
    I'm learning Java and OOP, and have been doing the problems at Project Euler for practice (awesome site btw). I find myself doing many of the same things over and over, like: checking if an integer is prime/generating primes generating the Fibonacci series checking if a number is a palindrome What is the best way to store and call these methods? Should I write a utility class and then import it? If so, do I import a .class file or the .java source? I'm working from a plain text editor and the Mac terminal. Thanks!

    Read the article

  • Using Remote Web Server to Initialize iPhone App

    - by Chris_K
    My iPhone app relies on a vendor's XML feed to provide data. But that feed is not locked down. The vendor could change the format of the XML at any time, although so far they've promised not to. Since I might want to tell my app to use a different URL for its data source, I'd like to set up a single "Command Central" Web page, on my own server, to direct the app to the correct data source. In other words, each time my app starts, in the background and unseen by the user, it would visit "http://www.myserver.com/iphoneapp_data_sources.xml" to retrieve the URL for retrieving data from my vendor. That way, if my vendor suddenly changes the exact URL or the XML feed that the app needs, I can update that Web page and ensure that all installations of the app are using the correct XML feed. Does anyone have any advice or examples showing this kind of approach? It seems as if this must be a common problem, but so far I haven't found a well-established design pattern that fits it.

    Read the article

  • Are protected constructors considered good practice?

    - by Álvaro G. Vicario
    I'm writing some little helper classes to handle trees. Basically, I have a node and a special root node that represents the tree. I want to keep it generic and simple. This is part of the code: <?php class Tree extends TreeNode{ public function addById($node_id, $parent_id, $generic_content){ if( $parent = $this->findNodeById($parent_id) ){ $parent->addChildById($node_id, $generic_content); } } } class TreeNode{ public function __construct($node_id, $parent_id, $generic_content){ // ... } protected function addChildById($node_id, $generic_content){ $this->children[] = new TreeNode($this->node_id, $node_id, $generic_content); } } $Categories = new Tree; $Categories->addById(1, NULL, $foo); $Categories->addById(2, NULL, $bar); $Categories->addById(3, 1, $gee); ?> My questions: Is it sensible to force TreeNode instances to be created through TreeNode::addById()? If it's so, would it be good practise to declare TreeNode::__construct() as private/protected?

    Read the article

  • Same project...multiple apps?

    - by greypoint
    We have a an iPhone app project that we wish to deploy multiple times under different client names. The individual apps will be very similar but will have different resources (icon, images etc) and config settings stored in plists (server names, options etc). What is the preferred means to manage this in Xcode? Obviously we really don't want different XCode projects for each App deployment since it's 90% shared code.

    Read the article

  • How should I architect JasperReports with a PHP front+backend system

    - by Itay Moav
    Our system is written completely in PHP. For various business reasons (which are a given) I need to build the reports of the system using JasperReports. What architecture should I use? Should I put the Jasper as a stand alone server (if possible) and let the php query against it, should I have it generate the reports with a cron, and then let the PHP scoop up the files and send them to the web client/browser...

    Read the article

  • typeof === "undefined" vs. != null

    - by Thor Thurn
    I often see JavaScript code which checks for undefined parameters etc. this way: if (typeof input !== "undefined") { // do stuff } This seems kind of wasteful, since it involves both a type lookup and a string comparison, not to mention its verbosity. It's needed because 'undefined' could be renamed, though. My question is: How is that code any better than this approach: if (input != null) { // do stuff } As far as I know, you can't redefine null, so it's not going to break unexpectedly. And, because of the type-coercion of the != operator, this checks for both undefined and null... which is often exactly what you want (e.g. for optional function parameters). Yet this form does not seem widespread, and it even causes JSLint to yell at you for using the evil != operator. Why is this considered bad style?

    Read the article

  • Being pressured to GOTO the dark-side

    - by Dan McG
    We have a situation at work where developers working on a legacy (core) system are being pressured into using GOTO statements when adding new features into existing code that is already infected with spagetti code. Now, I understand there may be arguments for using 'just one little GOTO' instead of spending the time on refactoring to a more maintainable solution. The issue is, this isolated 'just one little GOTO' isn't so isolated. At least once every week or so there is a new 'one little GOTO' to add. This codebase is already a horror to work with due to code dating back to or before 1984 being riddled with GOTOs that would make many Pastafarians believe it was inspired by the Flying Spagetti Monster itself. Unfortunately the language this is written in doesn't have any ready made refactoring tools, so it makes it harder to push the 'Refactor to increase productivity later' because short-term wins are the only wins paid attention to here... Has anyone else experienced this issue whereby everybody agrees that we cannot be adding new GOTOs to jump 2000 lines to a random section, but continually have Anaylsts insist on doing it just this one time and having management approve it? tldr; How can one go about addressing the issue of developers being pressured (forced) to continually add GOTO statements (by add, I mean add to jump to random sections many lines away) because it 'gets that feature in quicker'? I'm beginning to fear we may loses valuable developers to the raptors over this...

    Read the article

  • Is "for(;;)" faster than "while (TRUE)"? If not, why do people use it?

    - by Chris Cooper
    for (;;) { //Something to be done repeatedly } I have seen this sort of thing used a lot, but I think it is rather strange... Wouldn't it be much clearer to say while (TRUE), or something along those lines? I'm guessing that (as is the reason for many-a-programmer to resort to cryptic code) this is a tiny margin faster? Why, and is it REALLY worth it? If so, why not just define it this way: #DEFINE while(TRUE) for(;;)

    Read the article

  • Prims vs Polys: what are the pros and cons of each?

    - by Richard Inglis
    I've noticed that most 3d gaming/rendering environments represent solids as a mesh of (usually triangular) 3d polygons. However some examples, such as Second Life, or PovRay use solids built from a set of 3d primitives (cube, sphere, cone, torus etc) on which various operations can be performed to create more complex shapes. So my question is: why choose one method over the other for representing 3d data? I can see there might be benefits for complex ray-tracing operations to be able to describe a surface as a single mathematical function (like PovRay does), but SL surely isn't attempting anything so ambitious with their rendering engine. Equally, I can imagine it might be more bandwidth-efficient to serve descriptions of generalised solids instead of arbitrary meshes, but is it really worth the downside that SL suffers from (ie modelling stuff is really hard, and usually the results are ugly) - was this just a bad decision made early in SL's development that they're now stuck with? Or is it an artefact of what's easiest to implement in OpenGL?

    Read the article

  • Best practice for using Wcf service by silverlight?

    - by bonefisher
    How would you structure the code for calling a wcf service in silverlight application? Using only-once instanciated wcf service-proxy (aka singleton) and using it across the whole SL app? If so, how did you solve the unsubscribing controls from ws-call-completed event? or creating the wcf service-proxy for each ws-call? Where do you close the proxy then?

    Read the article

  • How to implement "drag n drop" user interface on website?

    - by Nikkeloodeni
    Hello, I was wondering what would be the best way to implement some kind of "drag n drop" user interface? What i mean is that there would be one main page and every link click (eg. other sections like about, gallery, contact form) would open a new drag n drop element on top of that main page. Something like windows desktop where you can move your application windows around the screen. Would it be best to call different functions with AJAX when a link is clicked? Like "gallery" link would call gallery-function and retrieve dynamically generated contents of that "window" with AJAX call and then just load that stuff on some div? Or would some other type of approach suit better for this? I hope I was able to explain this clearly enough. I'm looking for a proper "design pattern" to implement this. All suggestions are wellcome! :)

    Read the article

  • Saving a Django form with a Many2Many field with through table

    - by PhilGo20
    So I have this model with multiple Many2Many relationship. 2 of those (EventCategorizing and EventLocation are through tables/intermediary models) class Event(models.Model): """ Event information for Way-finding and Navigator application""" categories = models.ManyToManyField('EventCategorizing', null=True, blank=True, help_text="categories associated with the location") #categories associated with the location images = models.ManyToManyField(KMSImageP, null=True, blank=True) #images related to the event creator = models.ForeignKey(User, verbose_name=_('creator'), related_name="%(class)s_created") locations = models.ManyToManyField('EventLocation', null=True, blank=True) In my view, I first need to save the creator as the request user, so I use the commit=False parameter to get the form values. if event_form.is_valid(): event = event_form.save(commit=False) #we save the request user as the creator event.creator = request.user event.save() event = event_form.save_m2m() event.save() I get the following error: *** TypeError: 'EventCategorizing' instance expected I can manually add the M2M relationship to my "event" instance, but I am sure there is a simpler way. Am I missing on something ?

    Read the article

  • user interface pattern for associating single or many objects to an entity

    - by Samuel
    Need suggestions on implementing associating single or many objects to an entity. All soccer team players are registered individually (e.g. they are part of 'players' table) A soccer team has many players. The click sequence is like this:- a] Soccer team owner provides a name and brief description of the soccer team. b] Now it wants to add players to this team. c] You have the following button 'Add players to team' which lets you navigate to the 'View Players' page and lets you multi select users from there. Assuming this is a paginated list of players, how do you handle the following:- Do you provide a check box against each player and let the manager do a multi selection. If you need to add more players, it doesn't make sense to show the players who have been already added to the team. Do you mark those entries as not selectable or you would adding showing these entries. If you need to filter, do you provide search filters at the top of this page. Am looking for ideas on how to implement this or sites which have already done something similar.

    Read the article

  • how to tackle a new project

    - by stevo
    Hi, I have a question about best practice on how to tackle a new project, any project. When starting a new project how do you go about tackling the project, do you split it into sections, start writing code, draw up flow diagrams. I'm asking this question because I'm looking for advice on how I can start new projects so I can get going on them quicker. I can have it planned, designed and starting coding with everything worked out. Any advice? Thanks Stephen

    Read the article

  • Should a C++ constructor do real work?

    - by Wade Williams
    I'm strugging with some advice I have in the back of my mind but for which I can't remember the reasoning. I seem to remember at some point reading some advice (can't remember the source) that C++ constructors should not do real work. Rather, they should initialize variables only. The advice when on to explain that real work should be done in some sort of init() method, to be called separately after the instance was created. The situation is I have a class that represents a hardware device. It makes logical sense to me for the constructor to call the routines that query the device in order to build up the instance variables that describe the device. In other words, once new instantiates the object, the developer receives an object which is ready to be used, no separate call to object-init() required. Is there a good reason why constructors shouldn't do real work? Obviously it could slow allocation time, but that wouldn't be any different if calling a separate method immediately after allocation. Just trying to figure out what gotchas I not currently considering that might have lead to such advice.

    Read the article

  • Should I use a modified singleton design pattern that only allows one reference to its instance?

    - by Graham
    Hi, I have a class that would normally just generate factory objects, however this class should only used once throughout the program in once specifix place. What is the best design pattern to use in this instance? I throught that having a modified singleton design which only allows one reference to instance throughout the program would be the correct way to go. So only the first call to getInstance() returns the factory library. Is this a good or bad idea? Have I missed out another fundermental design pattern for solving this problem? Thanks for your help.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 158 159 160 161 162 163 164 165 166 167 168 169  | Next Page >