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  • Database Design Question: GUID + Natural Numbers

    - by Alan
    For a database I'm building, I've decided to use natural numbers as the primary key. I'm aware of the advantages that GUID's allow, but looking at the data, the bulk of row's data were GUID keys. I want to generate XML records from the database data, and one problem with natural numbers is that I don't want to expose my database key's to the outside world, and allow users to guess "keys." I believe GUID's solve this problem. So, I think the solution is to generate a sparse, unique iD derived from the natural ID (hopefully it would be 2-way), or just add an extra column in the database and store a guid (or some other multibyte id) The derived value is nicer because there is no storage penalty, but it would be easier to reverse and guess compared to a GUID. I'm (buy) curious as to what others on SO have done, and what insights they have.

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  • Design advices for quick navigation between view

    - by Thomas Joulin
    Usually, when a View requires a lot of bindings, or some UI Elements like a Bing Map, it takes a "while" to load (like between half a second and a second). I don't want a delay between a "tap" action (like tapping an element on a ListBox) and the navigation action (displaying a new page). I don't mind displaying the page progressively. For example, for a Bing Map, I don't mind displaying a black page with only a title, and a second later, having the Map appear. What are the best practices ? It could post a sample if i'm not clear enough

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  • Rails: Design Pattern to Store Order of Relations

    - by ChrisInCambo
    Hi, I have four models: Customer, QueueRed, QueueBlue, QueueGreen. The Queue models have a one to many relationship with customers A customer must always be in a queue A customer can only be in one queue at a time A customer can change queues We must be able to find out the customers current position in their respective queue In an object model the queues would just have an array property containing customers, but ActiveRecord doesn't have arrays. In a DB I would probably create some extra tables just to handle the order of the stories in the queue. My question is what it the best way to model the relationship in ActiveRecord? Obviously there are many ways this could be done, but what is the best or the most in line with how ActiveRecord should be used? Cheers, Chris

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  • Why is textbox.focus throwing the lostfocus event?

    - by cost
    I've seen a few similar questions on SO but nothing that seems to actually address the issue. Here's a simplified version of the function. Private Sub Check_Quantity(sender As System.Object, e As System.Windows.RoutedEventArgs) _ Handles textbox_quantity.LostFocus Dim worked As Boolean = Integer.TryParse(textbox_quantity.Text, quantity) If Not worked Then MsgBox("Enter a valid number for the quantity") textbox_quantity.Focus() textbox_quantity.SelectAll() quantity = 0 End If End Sub It's important to note that this is WPF. What I want to do is very simple. When someone finishes with the textbox the program checks that what they entered is a number. If it does it sticks this in an integer. If not, it tells them to fix it and keeps the focus on the textbox. The issue is a few things, but what it comes down to is this function runs in an infinite loop. This same function works fine in WinForms, but not in WPF. On some other questions people have said that the messagebox appearing causes focus to be lost, but in testing this isn't true. It still loops regardless of if the messagebox is called or not. The problem is the call to textbox_quantity.Focus(). Without that it works fine. Regardless of whether it's there or not though, focus is not set to the textbox, though textbox_quantity.Focus() still returns a value of true. Any thought of what's going on and maybe how I could fix it?

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  • drupal adding onchange event to node form

    - by Arun
    hi i need to know how to add attribute onchange to a custom content_type field? For ex my content_type has 2 fields phone (name:field_phone[0][value], id:edit-field-phone-0-value),email (name:field_email[0][value], id:edit-field-email-0-value). i'm unable to add attribute as follows. function knpevents_form_event_node_form_alter(&$form, &$form_state) { $form['title']['#attributes'] = array('onchange' => "return titlevalidate(0)");//fine $form['field_evt_org[0][value]']['#attributes']= array('onchange' => "return organiservalidate(0)"); //error $form['field_evt_org[0][value]']['#attributes']= array('onchange' => "return organiservalidate(0)"); //error } how to add it

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  • Finding out event that called a CGI script

    - by Acorn
    What I want is to be able to make my CGI script do different things depending on what action initiated the calling of the script. For example, if one button is pressed, a database is cleared. If another button is pressed, a form is submitted and that data is added to the database. Should I be doing something like adding the name of the form/button to the end of the POST data submitted in jQuery and then .poping it off in the script? Or is there some other data that's already sent in the POST that I could get from FieldStorage that would give me the information I need to decide what the script should do when it's called? And what if I wasn't using javascript? Would I have to have a hidden field that gets submitted with the name of the form/button? Or is it best to use a different target script for each button on a page?

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  • ActionScript 2: Event doesn't fire?

    - by Pascal Schuster
    So I have a soundHandler class that's supposed to play sounds and then point back to a function on the timeline when the sound has completed playing. But somehow, only one of the sounds plays when I try it out. EDIT: After that sound plays, nothing happens, even though I have EventHandlers set up that are supposed to do something. Here's the code: import mx.events.EventDispatcher; class soundHandler { private var dispatchEvent:Function; public var addEventListener:Function; public var removeEventListener:Function; var soundToPlay; var soundpath:String; var soundtype:String; var prefix:String; var mcname:String; public function soundHandler(soundpath:String, prefix:String, soundtype:String, mcname:String) { EventDispatcher.initialize(this); _root.createEmptyMovieClip(mcname, 1); this.soundpath = soundpath; this.soundtype = soundtype; this.prefix = prefix; this.mcname = mcname; } function playSound(file, callbackfunc) { _root.soundToPlay = new Sound(_root.mcname); _global.soundCallbackfunc = callbackfunc; _root.soundToPlay.onLoad = function(success:Boolean) { if (success) { _root.soundToPlay.start(); } }; _root.soundToPlay.onSoundComplete = function():Void { trace("Sound Complete: "+this.soundtype+this.prefix+this.file+".mp3"); trace(arguments.caller); dispatchEvent({type:_global.soundCallbackfunc}); trace(this.toString()); trace(this.callbackfunction); }; _root.soundToPlay.loadSound("../sound/"+soundpath+"/"+soundtype+prefix+file+".mp3", true); _root.soundToPlay.stop(); } } Here's the code from the .fla file: var playSounds:soundHandler = new soundHandler("signup", "su", "s", "mcs1"); var file = "000"; playSounds.addEventListener("sixtyseconds", this); playSounds.addEventListener("transition", this); function sixtyseconds() { trace("I am being called! Sixtyseconds"); var phase = 1; var file = random(6); if (file == 0) { file = 1; } if (file<10) { file = "0"+file; } file = phase+file; playSounds.playSound(file, "transition"); } function transition() { trace("this works"); } playSounds.playSound(file, "sixtyseconds"); I'm at a total loss for this one. Have been wasting hours to figure it out already. Any help will be deeply appreciated.

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  • Avoid postback on gridview event

    - by purushottam
    1 I've got popup (using javascript) working in a kind of gridview. When you click a button on one grid, it displays a popup window containing another grid of information, based on the row clicked in the first grid. This works well... I've enabled editing in the grid that is popped up. When you click edit though, the popup window disappears. If I click the display button in the first grid though to bring the popup window visible again it displays, and is now in edit mode. Is there a way to make postbacks in the popup not close the popup?

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  • Add event to all elements except the given with jQuery

    - by Metropolis
    Hey everyone I created a date picker that uses ajax to populate an element with an id of calendarContainer. When the user clicks on a button to bring the calendar up, I want the user to be able to click anywhere else on the screen besides the calendar and have it hide. The calendarContainer is at the root of the dom and I have tried everything I can think of to get this working. I have gotten the calendar to go away when it is not clicked on. However, when I click on the calendar it is also going away. I only want the calendar to go away when it is not clicked on. Here are all of the things I have tried. $(":not(#calendarContainer > table)").live('click', function() { $.Calendar.hide(); }); $(":not(#calendarContainer").live('click', function() { $.Calendar.hide(); }); $(":not(#calendarContainer)").click(function() { $.Calendar.hide(); }); $("body:not(#calendarContainer)").click(function() { $.Calendar.hide(); }); $(":not(#calendarContainer, #calendarData)").live('click', function() { $.Calendar.hide(); }); Thanks for any help, Metropolis

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  • VMware event hooks in .NET

    - by Henry Jackson
    I'm developing an in-house .NET application that will be run on a VM (with VMware), and want to know if there's a way to get notifications from VM system events (like suspending, resumed, etc.) Anyone know of a convenient way to do that? The virtual machine has VMware Tools installed, does that provide a .NET API for hooking events?

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  • [MacOS] Visio-like design software? [closed]

    - by OverTheRainbow
    Hello It's a software-related question but not development-related :-/ A friend of mine is looking for an equivalent on Macintosh to Visio or SmarDraw to draw plans for home improvements. I don't know anything about Macintosh, so would appreciate any feedback on good softwares for this type of applications. Thank you.

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  • Group by query design help

    - by Midhat
    Consider this data PK field1 field2 1 a b 2 a (null) 3 x y 4 x z 5 q w I need to get this data select all columns from all rows where field1 has count 1 i tried and finally settled for select * from mytable where field1 in (select field1 from mytable group by field1 having count(field1)>1 ) order by field1 but there has to be a better way than this

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  • best database design for city zip & state tables

    - by ryan a
    My application will need to reference addresses. Street info will be stored with my main objects but the rest needs to be stored seperately to reduce redundancy. How should I store/retrieve ZIPs, cities and states? Here are some of my ideas. single table solution (cant do relationships) [locations] locationID locationParent (FK for locationID - 0 for state entries) locationName (city, state) locationZIP two tables (with relationships, FK constraints, ref integrity) [state] stateID stateName [city] cityID stateID (FK for state.stateID) cityName zipCode three tables [state] stateID stateName [city] cityID stateID (FK for state.stateID) cityName [zip] zipID cityID (FK for city.cityID) zipName Then I read into ZIP codes amd how they are assigned. They aren't specifically related to cities. Some cities have more than one ZIP (ok will still work) but some ZIPs are in more than one city (oh snap) and some other ZIPs (very few) are in more than one state! Also some ZIPs are not even in the same state as the address they belong to at all. Seems ZIPs are made for carrier route identification and some remote places are best served by post offices in neighboring cities or states. Does anybody know of a good (not perfect) solution that takes this into consideration to minimize discrepencies as the database grows?

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  • Design question?

    - by Mohamed
    I am building music app, where user can do several tasks including but not limited to listening song, like song, recommend song to a friend and extra. currently I have this model: class Activity(models.Model): activity = models.TextField() user = models.ForeignKey(User) date = models.DateTimeField(auto_now=True) so far I thought about two solutions. 1. saving a string to database. e.g "you listened song xyz" 2. create a dictionary about the activity and save to the database using pickle or json. e.g. dict_ = {"activity_type":"listening", "song":song_obj} I am leaning to the second implementation, but not quite sure. so what do you think about those two methods? do you know better way to achieve the goal?

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  • Qt/C++ event loop exception handling

    - by Georg
    I am having an application heavily based on QT and on a lot of third party libs. THese happen to throw some exceptions in several cases. In a native Qt App this causes the application to abort or terminate. Often the main data model is still intact as I am keeping it in pure Qt with no external data. So I am thinking that I could also just recover by telling the user that there has occured an error in this an that process and he should save now or even decide to continue working on the main model. Currently the program jsut silently exits without even telling a story. Please help.

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  • Win32 reset event like synchronization class with boost C++

    - by fgungor
    I need some mechanism reminiscent of Win32 reset events that I can check via functions having the same semantics with WaitForSingleObject() and WaitForMultipleObjects() (Only need the ..SingleObject() version for the moment) . But I am targeting multiple platforms so all I have is boost::threads (AFAIK) . I came up with the following class and wanted to ask about the potential problems and whether it is up to the task or not. Thanks in advance. class reset_event { bool flag, auto_reset; boost::condition_variable cond_var; boost::mutex mx_flag; public: reset_event(bool _auto_reset = false) : flag(false), auto_reset(_auto_reset) { } void wait() { boost::unique_lock<boost::mutex> LOCK(mx_flag); if (flag) return; cond_var.wait(LOCK); if (auto_reset) flag = false; } bool wait(const boost::posix_time::time_duration& dur) { boost::unique_lock<boost::mutex> LOCK(mx_flag); bool ret = cond_var.timed_wait(LOCK, dur) || flag; if (auto_reset && ret) flag = false; return ret; } void set() { boost::lock_guard<boost::mutex> LOCK(mx_flag); flag = true; cond_var.notify_all(); } void reset() { boost::lock_guard<boost::mutex> LOCK(mx_flag); flag = false; } }; Example usage; reset_event terminate_thread; void fn_thread() { while(!terminate_thread.wait(boost::posix_time::milliseconds(10))) { std::cout << "working..." << std::endl; boost::this_thread::sleep(boost::posix_time::milliseconds(1000)); } std::cout << "thread terminated" << std::endl; } int main() { boost::thread worker(fn_thread); boost::this_thread::sleep(boost::posix_time::seconds(1)); terminate_thread.set(); worker.join(); return 0; } EDIT I have fixed the code according to Michael Burr's suggestions. My "very simple" tests indicate no problems. class reset_event { bool flag, auto_reset; boost::condition_variable cond_var; boost::mutex mx_flag; public: explicit reset_event(bool _auto_reset = false) : flag(false), auto_reset(_auto_reset) { } void wait() { boost::unique_lock<boost::mutex> LOCK(mx_flag); if (flag) { if (auto_reset) flag = false; return; } do { cond_var.wait(LOCK); } while(!flag); if (auto_reset) flag = false; } bool wait(const boost::posix_time::time_duration& dur) { boost::unique_lock<boost::mutex> LOCK(mx_flag); if (flag) { if (auto_reset) flag = false; return true; } bool ret = cond_var.timed_wait(LOCK, dur); if (ret && flag) { if (auto_reset) flag = false; return true; } return false; } void set() { boost::lock_guard<boost::mutex> LOCK(mx_flag); flag = true; cond_var.notify_all(); } void reset() { boost::lock_guard<boost::mutex> LOCK(mx_flag); flag = false; } };

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  • Jquery Change event for input and select elements

    - by Abs
    Hello all, I am trying to alert something when ever a drop down box changes and when ever something is typed into an input. I don't think I can use change for input fields? What would you use for input fields? Also, what about input fields of type file? Same thing. Here is what I have so far and its not working: $('input#wrapper, select#wrapper').change(function(){ alert('You changed.'); }); Thanks all

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  • How to Design Programs: An Introduction to Programming and Computing -- teacher guide access

    - by user295683
    Hello -- I'm a biologist switching careers, and trying to learn programming as a result. I stumbled upon the aforementioned book on Amazon, which jived with my liberal arts background. Despite my great satisfaction with the didactic approach, I was frustrated to see that the answers to the exercises are restricted to teachers only. As I am pursuing this endeavor on my own, this restriction dramatically cripples the value of this book. My request to the author's website for access to the answers has not been answered, and I would desperately like to continue with this book. Anyone have any experience dealing with the book's website, or at the very least a torrent of the answers? Otherwise, I suspect I will be relegated to using JavaScript for everything! Thanks!

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  • Polling a web URL until event

    - by Jaxo
    I'm really sorry about the crappy title - if anybody has a better way of wording it, please edit it! I basically need to have a C# application run a function if the output of a URL is a certain value. For example, if the website says blue the background colour will be blue, red to make it red, etc. The problem is I don't want to spam my webserver with checks. The 4 bytes it downloads each time is negligible, but if I were to deploy this type of system on multiple computers, it would get slower and slower and the bandwidth would add up quickly. So my question is: How can my desktop application run a piece of code only when a web URL has a different output without checking each time? I can't use sockets, and any sort of LAN protocol won't end up working. My reasoning behind this potentially nefarious code is to be able to mute computers by updating a file on the website (as you may have seen in my previous question today, sorry!). I'd like it to be rather quick, and not have the refresh time minutes apart, a few seconds at the most would be ideal. How can I accomplish this? The website's code is easy, but getting the C# application to check when it changes is the part I'm stuck on. Nothing shows up on the website other than the command. Thanks!

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  • Determining the chances of an event occurring when it hasn't occurred yet

    - by sanity
    A user visits my website at time t, and they may or may not click on a particular link I care about, if they do I record the fact that they clicked the link, and also the duration since t that they clicked it, call this d. I need an algorithm that allows me to create a class like this: class ClickProbabilityEstimate { public void reportImpression(long id); public void reportClick(long id); public double estimateClickProbability(long id); } Every impression gets a unique id, and this is used when reporting a click to indicate which impression the click belongs to. I need an algorithm that will return a probability, based on how much time has past since an impression was reported, that the impression will receive a click, based on how long previous clicks required. Clearly one would expect that this probability will decrease over time if there is still no click. If necessary, we can set an upper-bound, beyond which we consider the click probability to be 0 (eg. if its been an hour since the impression occurred, we can be pretty sure there won't be a click). The algorithm should be both space and time efficient, and hopefully make as few assumptions as possible, while being elegant. Ease of implementation would also be nice. Any ideas?

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  • GridBoundColumn OnTextChanged event wiring

    - by Kobojunkie
    I have a GridBoundColumn in my RadGrid that should accept Zip input and based on input auto populates the State and City fields on my form. I would like to wire this up in such a way as to call a webservice on the back end or maybe repost the form only when the GridBoundColumn is changed. How do I wire this up please? Thanks in Advance

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