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• Sample/Example needed for a table/field setup

  - by acctman

  Can someone explain the statement below to me with a working sample/example. thanks in advance. You can not create duplicate fields, but simply add a single extra field, "coupleId", which would have a unique id for each couple; and two rows (one for each person) per couple; then JOIN the table against itself with a constraint like a.coupleId = b.coupleId AND a.id < b.id so that you can condense the data into a single result row for a given couple.

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• Is Graphics.DrawImage asynchronous?

  - by Roy

  Hi all, I was just wondering, is Graphics.DrawImage() asynchronous? I'm struggling with a thread safety issue and can't figure out where the problem is. if i use the following code in the GUI thread: protected override void OnPaint(PaintEventArgs e) { lock (_bitmapSyncRoot) { e.Graphics.DrawImage(_bitmap, _xPos, _yPos); } } And have the following code in a separate thread: private void RedrawBitmapThread() { Bitmap newBitmap = new Bitmap(_width, _height); // Draw bitmap // Bitmap oldBitmap = null; lock (_bitmapSyncRoot) { oldBitmap = _bitmap; _bitmap = newBitmap; } if (oldBitmap != null) { oldBitmap.Dispose(); } Invoke(Invalidate); } Could that explain an accessviolation exception? The code is running on a windows mobile 6.1 device with compact framework 3.5.

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• Javascript Prototyping Question

  - by Nick Lowman

  I'm just reading about Prototypes in JavaScript and Douglas Crockford offers and excellent way to select a new objects prototype but can anyone explain (below) why obj01's type equals 'object' when I pass it in function as it's prototype? if (typeof Object.beget !== 'function') { Object.beget = function (o) { console.log(typeof o);//function var F = function () {}; F.prototype = o; console.log(typeof F);//function return new F(); }; } var func01 = function(){}; var obj01 = Object.beget(func01); console.log(typeof obj01);//object console.log(typeof obj01.prototype);//object I thought it would be console.log(typeof obj01);//function console.log(typeof obj01.prototype);//function

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• SQL SELECT with time range

  - by nLL

  Hi, I have below click_log table logging hits for some urls site ip ua direction hit_time ----------------------------------------------------- 1 127.0.0.1 1 20010/01/01 00:00:00 2 127.0.0.1 1 20010/01/01 00:01:00 3 127.0.0.1 0 20010/01/01 00:10:00 .... ......... I want to select incoming hits (direction:1) and group by sites that are: from same ip and browser logged within 10 minutes of each other occured more than 4 times in 10 minutes. I'm not sure if above was clear enough. English is not my first language. Let me try to explain with an example. If site 1 gets 5 hits from same ip and browser with in 10 minutes after getting first unique hit from that ip and browser i want it to be included in the selection. Basically I am trying to find abusers.

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• Create DataGridView columns from Table values

  - by fireBand

  Hi, I am using data grid view to display items as excel spread sheet in VB.NET. I got a table named CostTypes with column names [CostTypeID, CostType] and values [1,External] and [2,Internal] (These are constant but more values can be added to table). I want to create columns with names of the values[External , Internal] in DataGridView. If I use databiding directly I get columns [CostTypeID,CostType] which is not what I am looking for. If some one could explain how to create columns at runtime in datagridview or how to retrieve data from data base using LINQ so that [External , Internal] turn out to be columns that would be great. Thanks in advance.

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• Javascript array length incorrect on array of objects

  - by Serenti

  Could someone explain this (strange) behavior? Why is the length in the first example 3 and not 2, and most importantly, why is the length in the second example 0? As long as the keys are numerical, length works. When they are not, length is 0. How can I get the correct length from the second example? Thank you. a = []; a["1"] = {"string1":"string","string2":"string"}; a["2"] = {"string1":"string","string2":"string"}; alert(a.length); // returns 3 b = []; b["key1"] = {"string1":"string","string2":"string"}; b["key2"] = {"string1":"string","string2":"string"}; alert(b.length); // returns 0

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• How can I paste an image from the clipboard into a web form?

  - by dr. squid

  I found this question, but the question is about how to get an image from the clip board into a wyziwyg editor! My question is "How can I paste an image from the clipboard into a field (what field is not that big issue as long as it works)", and then sent to the server. Jira has this functionality, so it should be possible! Any ideas on how to do this? Just to explain the complete workflow; I would like to have a plave to multi upload images, where the paste from clipboard also is an option. The upload will be some ajax of some sort, bt is not important in this context! Thanks

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• MongoDB map/reduce counts

  - by ibz

  The output from MongoDB's map/reduce includes something like 'counts': {'input': I, 'emit': E, 'output': O}. I thought I clearly understand what those mean, until I hit a weird case which I can't explain. According to my understanding, counts.input is the number of rows that match the condition (as specified in query). If so, how is it possible that the following two queries have different results? db.mycollection.find({MY_CONDITION}).count() db.mycollection.mapReduce(SOME_MAP, SOME_REDUCE, {'query': {MY_CONDITION}}).counts.input I thought the two should always give the same result, independent of the map and reduce functions, as long as the same condition is used.

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• Looking for an algorithm in vb.net or c# but I don't know it's name!

  - by Jules

  I'll do my best to explain what the algorithm is supposed to do: There's a class 'Recipe'. Each Recipe can include other Recipes but cannot include itself or any other Recipe that includes it. So, a simple example is we have just two Recipes A & B. If A adds B first, then later on B cannot add A because it will cause a loop. A more complicated example is: A,B,C (1) Recipe C Adds B (2) Recipe B Adds A (3) Recipe A attempts to add C, but can't because of the relationship. C - B - A. I can do this myself, I just wondered if this was a standard named algorithm and I could grab the optimal solution. Thanks

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• How to use Git properly with XCode?

  - by rickharrison

  I have been an iphone developer for a while, and I have recently been including git in my workflow. I have used git settings found on http://shanesbrain.net/2008/7/9/using-xcode-with-git for my workflow so far. Those settings tell git to exclude *.pbxproj from merges? Is there a real reason for doing this? For example, when I add a file to the project and push to origin, my fellow developers will not have that file added to their xcode project when they pull. Then if one of them builds a release this file may not be included. Shouldn't I just let git handle the merges for the project file? Could someone please explain why or why not this file should be in merges and how to properly handle the situation when files are added to the project. Thanks.

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• functions in F# .. why is it not compiling

  - by Tanmoy

  Hi, I have written two versions of code. The first one works as expected and print "Hi". the second one gives me error that "block following this let is unfinished" 1st version #light let samplefn() = let z = 2 let z = z * 2 printfn "hi" samplefn() 2nd version #light let samplefn() = let z = 2 let z = z * 2 samplefn() Only difference is the printfn is absent in the second version. I am using Visual Studio 2010 as my IDE. I am very new to F# but this error seems very strange to me. I guess I am missing some very important concept. Please explain. Edit: Also if I do it outside the function I get error even with the first version of code. #light let z = 2 let z = z * 2 printfn "Error: Duplicate definition of value z"

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• urllib alternative for iPhone

  - by Pr301

  hi, I am trying to create an iPhone application which in some point connects to the internet, fills an on-line form, fetches the resulting website, parses it and returns a string to the user. I want all this process to happen in the background. I know how to do this kind of things with python and urllib but in objc I can't find an alternative, from on-line search I found either sites that explain how to use webkit to retrieve webpages (I suppose this is for displaying them to the user) or how to parse an existing HTML file or string. Since I want the file to be retrieved from the internet and the whole process should be running in the background, neither of these solutions covers my needs.

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• Generics Type issue

  - by JohnJohnGa

  ArrayList<Integer> arrI = new ArrayList<Integer>(); ArrayList arrO = arrI; // Warning /* It is ok to add a String as it is an ArrayList of Objects but the JVM will know the real type, arrO is an arrayList of Integer... */ arrO.add("Hello"); /* How I can get a String in an ArrayList<Integer> ?? Even if the compiler told me that I will get an Integer! */ System.out.println(arrI.get(0)); Anybody can explain what's happening here?

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• How to get the "#" symbol in the :id into the redirect_to method in Rails

  - by Matthias Günther

  Hello, this is a silly questions but I don't understand, why rails isn't evaluating my string as expected. Here is my problem: I want to redirect to an url in the form ~/:controller/index/#_76 redirect_to :action => "index", :id => '#_76' But I'm getting the url in the form: ~/:controller/index/%25_76 and so my anchor for linking to a certain place in the website isn't working. Can someone please explain me, why rails makes this rendering? I think this hase something to do with url encoding. Again thanks for your help, I'm learning every day a little bit more about rails :).

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• interfacing: simplified

  - by code wombat

  i've been doing some research on interfaces and a simple layman's explanation for what it truly is. For some reason people love using overly complex explanations and jargon to explain truly simple concepts (guess it makes them feel big) and i have a gut feeling it's the same in this case. so from what i could grasp, it seems like interfaces are nothing more than a way to reserve method names, their return type if any, and the type and amount of arguments they accept. so when a class implements an interface (or interfaces) it is forced to define the body of each method from the interface(s). Am i on the nose with this one or do i need to keep digging? p.s. i know javascript doesn't have support for interfaces, but i still need to understand the concept because there are quite a few places where it's shown how to emulate to an extent.

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• Using enums or a set of classes when I know I have a finite set of different options?

  - by devoured elysium

  Let's say I have defined the following class: public abstract class Event { public DateTime Time { get; protected set; } protected Event(DateTime time) { Time = time; } } What would you prefer between this: public class AsleepEvent : Event { public AsleepEvent(DateTime time) : base(time) { } } public class AwakeEvent : Event { public AwakeEvent(DateTime time) : base(time) { } } and this: public enum StateEventType { NowAwake, NowAsleep } public class StateEvent : Event { protected StateEventType stateType; public MealEvent(DateTime time, StateEventType stateType) : base(time) { stateType = stateType; } } and why? I am generally more inclined to the first option, but I can't explain why. Is it totally the same or are any advantages in using one instead of the other? Maybe with the first method its easier to add more "states", altough in this case I am 100% sure I will only want two states: now awake, and now asleep (they signal the moments when one awakes and one falls asleep).

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• I have a problem with the following Java code

  - by Sanjeev

  public class b { public static void main(String[] args) { byte b = 1; long l = 127; // b = b + l; // 1 if I try this then it does not compile b += l; // 2 if I try this then it does compile System.out.println(b); } } I am using this code but I have problem: I don't understand why b=b+l; is not compiling but if I write b+=l; then it compiles and runs. Please explain why this happens.

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• Initializing structs in C++

  - by Neil Butterworth

  As an addendum to this question, what is going on here: #include <string> using namespace std; struct A { string s; }; int main() { A a = {0}; } Obviously, you can't set a std::string to zero. Can someone provide an explanation (backed with references to the C++ Standard, please) about what is actually supposed to happen here? And then explain for example): int main() { A a = {42}; } Are either of these well-defined? Once again an embarrassing question for me - I always give my structs constructors, so the issue has never arisen before.

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• How do Java mocking frameworks work?

  - by Amir Rachum

  This is NOT a question about which is the best framework, etc. I have never used a mocking framework and I'm a bit puzzled by the idea. How does it know how to create the mock object? Is it done in runtime or generates a file? How do you know its behavior? And most importantly - what is the work flow of using such a framework (what is the step-by-step for creating a test). Can anyone explain? You can choose whichever framework you like for example, just say what it is.

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• Jsp declaration element

  - by Stardust

  <%! class father { static int s = 0; } %> <% father f1 = new father(); father f2 = new father(); f1.s++; out.println(f2.s); // It must print "1" %> When I run the file, I got this error. Can anybody explain? "The field s cannot be declared static; static fields can only be declared in static or top level types"

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• Confused by this PHP Exception try..catch nesting

  - by Domenic

  Hello. I'm confused by the following code: class MyException extends Exception {} class AnotherException extends MyException {} class Foo { public function something() { print "throwing AnotherException\n"; throw new AnotherException(); } public function somethingElse() { print "throwing MyException\n"; throw new MyException(); } } $a = new Foo(); try { try { $a->something(); } catch(AnotherException $e) { print "caught AnotherException\n"; $a->somethingElse(); } catch(MyException $e) { print "caught MyException\n"; } } catch(Exception $e) { print "caught Exception\n"; } I would expect this to output: throwing AnotherException caught AnotherException throwing MyException caught MyException But instead it outputs: throwing AnotherException caught AnotherException throwing MyException caught Exception Could anyone explain why it "skips over" catch(MyException $e) ? Thanks.

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• what is the meaning of this code

  - by spific

  i have this code : use strict; use LWP::UserAgent; use warnings; my $ua = new LWP::UserAgent(agent => 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.5) Gecko/20060719 Firefox/1.5.0.5'); $ua->proxy([qw(http https)] => 'http://59.39.92.148:1080'); my $response = $ua->get("http://www.google.com"); print $response->code,' ', $response->message,"\n"; is the mean of code " open www.google.com with sock proxy"? pls explain for me .

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• Why isn't my Ruby object deleted when the last reference goes out of scope?

  - by Andrew Clegg

  Hi gurus, I've found a weird effect when trying to track down a memory leak in a Rails app. Can anyone explain what's going on here? Save this script as a plain Ruby script (Rails not necessary): class Fnord def to_s 'fnord' end end def test f = Fnord.new end test GC.start sleep 2 ObjectSpace.each_object do |o| puts o if o.is_a? Fnord end When I run this via ruby 1.8.7 (2009-06-12 patchlevel 174) [i486-linux] I get the following: bash $ ruby var_test fnord Although the variable f is out of scope, there are no other references to the single Fnord object, and I've garbage collected, the object still seems to exist. Is this a nefarious memory leak of some sort, or am I completely missing something about Ruby? Further, if I change the test method to this: def test f = Fnord.new f = nil end I get no output. But surely this should not change the semantics here? Many thanks!

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• access models and forms within modules

  - by sims

  Hi Stackers, What is the best way to access my models and forms from a controller of a module? Let's explain with "pictures": /application/module/storage/controllers/IndexController.php needs to call readAction in the class called storage_Model_Files in /application/module/storage/models/Files.php I've made this app's dir structure and these forms and models with zf.sh (Zend_Tool). I've read about all sorts of ways of manually including these files. I want to lazy load them much like everything is done automatically with the default module. I can't seem to find how in the docs. Does that make sense? I have: resources.frontController.moduleDirectory = APPLICATION_PATH "/modules" in my application.ini file. So I can access my controllers fine. Thanks for your help!

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• String intern puzzles

  - by Yob

  On this blog I found interesting String puzzles: --- Quote --- String te = "te", st = "st"; //"test".length(); String username = te + st; username.intern(); System.out.println("String object the same is: " + (username == "test")); prints String object the same is: true but uncomment the "test".length(); line and it prints String object the same is: false --- EoQ --- Being honest I don't understand why the outputs are different. Could you please explain me what's the cause of such behaviour?

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