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• Big Data – Evolution of Big Data – Day 3 of 21

  - by Pinal Dave

  In yesterday’s blog post we answered what is the Big Data. Today we will understand why and how the evolution of Big Data has happened. Though the answer is very simple, I would like to tell it in the form of a history lesson. Data in Flat File In earlier days data was stored in the flat file and there was no structure in the flat file.  If any data has to be retrieved from the flat file it was a project by itself. There was no possibility of retrieving the data efficiently and data integrity has been just a term discussed without any modeling or structure around. Database residing in the flat file had more issues than we would like to discuss in today’s world. It was more like a nightmare when there was any data processing involved in the application. Though, applications developed at that time were also not that advanced the need of the data was always there and there was always need of proper data management. Edgar F Codd and 12 Rules Edgar Frank Codd was a British computer scientist who, while working for IBM, invented the relational model for database management, the theoretical basis for relational databases. He presented 12 rules for the Relational Database and suddenly the chaotic world of the database seems to see discipline in the rules. Relational Database was a promising land for all the unstructured database users. Relational Database brought into the relationship between data as well improved the performance of the data retrieval. Database world had immediately seen a major transformation and every single vendors and database users suddenly started to adopt the relational database models. Relational Database Management Systems Since Edgar F Codd proposed 12 rules for the RBDMS there were many different vendors who started them to build applications and tools to support the relationship between database. This was indeed a learning curve for many of the developer who had never worked before with the modeling of the database. However, as time passed by pretty much everybody accepted the relationship of the database and started to evolve product which performs its best with the boundaries of the RDBMS concepts. This was the best era for the databases and it gave the world extreme experts as well as some of the best products. The Entity Relationship model was also evolved at the same time. In software engineering, an Entity–relationship model (ER model) is a data model for describing a database in an abstract way. Enormous Data Growth Well, everything was going fine with the RDBMS in the database world. As there were no major challenges the adoption of the RDBMS applications and tools was pretty much universal. There was a race at times to make the developer’s life much easier with the RDBMS management tools. Due to the extreme popularity and easy to use system pretty much every data was stored in the RDBMS system. New age applications were built and social media took the world by the storm. Every organizations was feeling pressure to provide the best experience for their users based the data they had with them. While this was all going on at the same time data was growing pretty much every organization and application. Data Warehousing The enormous data growth now presented a big challenge for the organizations who wanted to build intelligent systems based on the data and provide near real time superior user experience to their customers. Various organizations immediately start building data warehousing solutions where the data was stored and processed. The trend of the business intelligence becomes the need of everyday. Data was received from the transaction system and overnight was processed to build intelligent reports from it. Though this is a great solution it has its own set of challenges. The relational database model and data warehousing concepts are all built with keeping traditional relational database modeling in the mind and it still has many challenges when unstructured data was present. Interesting Challenge Every organization had expertise to manage structured data but the world had already changed to unstructured data. There was intelligence in the videos, photos, SMS, text, social media messages and various other data sources. All of these needed to now bring to a single platform and build a uniform system which does what businesses need. The way we do business has also been changed. There was a time when user only got the features what technology supported, however, now users ask for the feature and technology is built to support the same. The need of the real time intelligence from the fast paced data flow is now becoming a necessity. Large amount (Volume) of difference (Variety) of high speed data (Velocity) is the properties of the data. The traditional database system has limits to resolve the challenges this new kind of the data presents. Hence the need of the Big Data Science. We need innovation in how we handle and manage data. We need creative ways to capture data and present to users. Big Data is Reality! Tomorrow In tomorrow’s blog post we will try to answer discuss Basics of Big Data Architecture. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Short Season, Long Models - Dealing with Seasonality

  - by Michel Adar

  Accounting for seasonality presents a challenge for the accurate prediction of events. Examples of seasonality include: ·         Boxed cosmetics sets are more popular during Christmas. They sell at other times of the year, but they rise higher than other products during the holiday season. ·         Interest in a promotion rises around the time advertising on TV airs ·         Interest in the Sports section of a newspaper rises when there is a big football match There are several ways of dealing with seasonality in predictions. Time Windows If the length of the model time windows is short enough relative to the seasonality effect, then the models will see only seasonal data, and therefore will be accurate in their predictions. For example, a model with a weekly time window may be quick enough to adapt during the holiday season. In order for time windows to be useful in dealing with seasonality it is necessary that: The time window is significantly shorter than the season changes There is enough volume of data in the short time windows to produce an accurate model An additional issue to consider is that sometimes the season may have an abrupt end, for example the day after Christmas. Input Data If available, it is possible to include the seasonality effect in the input data for the model. For example the customer record may include a list of all the promotions advertised in the area of residence. A model with these inputs will have to learn the effect of the input. It is possible to learn it specific to the promotion – and by the way learn about inter-promotion cross feeding – by leaving the list of ads as it is; or it is possible to learn the general effect by having a flag that indicates if the promotion is being advertised. For inputs to properly represent the effect in the model it is necessary that: The model sees enough events with the input present. For example, by virtue of the model lifetime (or time window) being long enough to see several “seasons” or by having enough volume for the model to learn seasonality quickly. Proportional Frequency If we create a model that ignores seasonality it is possible to use that model to predict how the specific person likelihood differs from average. If we have a divergence from average then we can transfer that divergence proportionally to the observed frequency at the time of the prediction. Definitions: Ft = trailing average frequency of the event at time “t”. The average is done over a suitable period of to achieve a statistical significant estimate. F = average frequency as seen by the model. L = likelihood predicted by the model for a specific person Lt = predicted likelihood proportionally scaled for time “t”. If the model is good at predicting deviation from average, and this holds over the interesting range of seasons, then we can estimate Lt as: Lt = L * (Ft / F) Considering that: L = (L – F) + F Substituting we get: Lt = [(L – F) + F] * (Ft / F) Which simplifies to: (i)                  Lt = (L – F) * (Ft / F)  +  Ft This latest expression can be understood as “The adjusted likelihood at time t is the average likelihood at time t plus the effect from the model, which is calculated as the difference from average time the proportion of frequencies”. The formula above assumes a linear translation of the proportion. It is possible to generalize the formula using a factor which we will call “a” as follows: (ii)                Lt = (L – F) * (Ft / F) * a  +  Ft It is also possible to use a formula that does not scale the difference, like: (iii)               Lt = (L – F) * a  +  Ft While these formulas seem reasonable, they should be taken as hypothesis to be proven with empirical data. A theoretical analysis provides the following insights: The Cumulative Gains Chart (lift) should stay the same, as at any given time the order of the likelihood for different customers is preserved If F is equal to Ft then the formula reverts to “L” If (Ft = 0) then Lt in (i) and (ii) is 0 It is possible for Lt to be above 1. If it is desired to avoid going over 1, for relatively high base frequencies it is possible to use a relative interpretation of the multiplicative factor. For example, if we say that Y is twice as likely as X, then we can interpret this sentence as: If X is 3%, then Y is 6% If X is 11%, then Y is 22% If X is 70%, then Y is 85% - in this case we interpret “twice as likely” as “half as likely to not happen” Applying this reasoning to (i) for example we would get: If (L < F) or (Ft < (1 / ((L/F) + 1)) Then  Lt = L * (Ft / F) Else Lt = 1 – (F / L) + (Ft * F / L)  

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• Do I need a Point and a Vector object? Or just using a Vector object to represent a Point is ok?

  - by JCM

  Structuring the components of an engine that I am developing along with a friend (learning purposes), I came to this doubt. Initially we had a Point constructor, like the following: var Point = function( x, y ) { this.x = x; this.y = y; }; But them we started to add some Vector math to it, and them decided to rename it to Vector2d. But now, some methods are a bit confusing (at least in my opinion), such as the following, which is used to make a line: //before the renaming of Point to Vector2, the parameters were startingPoint and endingPoint Geometry.Line = function( startingVector, endingVector ) { //... }; I should make a specific constructor for the Point object, or there are no problems in defining a point as a vector? I know a vector have magnitude and direction, but I see so many people using a vector to just represent the position of an object.

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• Magento - Fatal error: Class name must be a valid object or a string

  - by Jason Millward

  I'm having a problem with a Magento installation that I hope someone can help me with. I suddenly started getting the following error message when I accessed the site: Fatal error: Class name must be a valid object or a string in /app/code/core/Mage/Core/Model/Resource.php on line 215 I've searched for someone with a similar issue but not had any luck so i'm stuck and really need to get this resolved Can anyone help?

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• getJSON not working if the mvc model view controller has a parameter

  - by Paul

  I'm having an issue with a callback. I'm not even getting an error in Firebug. If I alert before and after the getjson call both alerts show but the getjson call doesn't fire. public ActionResult TestPage() { return View(); } public ActionResult LoadMapLonLats(int mapId) { //some code return Json(_myMaps); } $("#Search").click(function() { $.getJSON("LoadMapLonLats", { mapId: 73 }, loadDbMap); }); function loadDbMap(maps) { alert('m'); $.each(maps, function(i) { alert(maps[i]); }); } As long as I leave TestPage without a parameter is works. If I add a parameter to TestPage(int id) then the call back to LoadMapLonLats doesn't work. Seems odd. Of course TestPage is the page I'm loading so I need to do some work here before rendering the page. Not sure why adding a parameter to the view would break the callback to another function. //this breaks he callback to LoadMapLonLats public ActionResult TestPage(int id) { return View(); } Any ideas? Seems like this may be related, if not sorry I can post a new thread.

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• Is there a way to serialize a .Net MailMessage object

  - by Matt Dawdy

  I am trying to write a proc that will take in as a parameter a MailMessage object, and the split it apart to store the subject, body, to addresses, from address, and attachments (the hard part) in a database so the email can be sent at some point in the future. My first take on this was to rip out the parts I need and store them in a database, and that works great except for attachments. I can't figure out how to loop through the collection and then actually do anything with them. It there an easy way to serialize a MailMessage object that will actually take the content of the attachments with it? Am I doing this all wrong? Has anyone done this before?

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• Use Html.RadioButtonFor and Html.LabelFor for the same Model but different values

  - by Marc

  I have this Razor Template <table> <tr> <td>@Html.RadioButtonFor(i => i.Value, "1")</td> <td>@Html.LabelFor(i => i.Value, "true")</td> </tr> <tr> <td>@Html.RadioButtonFor(i => i.Value, "0")</td> <td>@Html.LabelFor(i => i.Value, "false")</td> </tr> </table> That gives me this HTML <table> <tr> <td><input id="Items_1__Value" name="Items[1].Value" type="radio" value="1" /></td> <td><label for="Items_1__Value">true</label></td> </tr> <tr> <td><input checked="checked" id="Items_1__Value" name="Items[1].Value" type="radio" value="0" /></td> <td><label for="Items_1__Value">false</label></td> </tr> </table> So I have the ID Items_1__Value twice which is - of course - not good and does not work in a browser when I click on the second label "false" the first radio will be activated. I know I could add an own Id at RadioButtonFor and refer to that with my label, but that's not pretty good, is it? Especially because I'm in a loop and cannot just use the name "value" with an added number, that would be end up in multiple Dom Ids in my final HTML markup as well. Shouldn't be a good solution for this?

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• MVVM- Trigger Storyboard in the View Model in Silverlight

  - by user275561

  I have a couple of Storyboards in my view that I would like to trigger from the ViewModel if possible. Is there a simple way or elegant way of doing this. Here is what I am trying to do. Person Clicks on a Button--RelayCommand (In the ViewModel), the Relay Command should then play the storyboard. Also one more thing, I would like to also trigger the storyboard animation by itself in the ViewModel without any interaction. <i:Interaction.Triggers> <i:EventTrigger EventName="MouseLeftButtonDown"> <cmd:EventToCommand Command="{Binding ButtonPress}" CommandParameterValue="RedButtonLight"> </cmd:EventToCommand> </i:EventTrigger> </i:Interaction.Triggers>

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• Language Agnostic Basic Programming Question

  - by Rachel

  This is very basic question from programming point of view but as I am in learning phase, I thought I would better ask this question rather than having a misunderstanding or narrow knowledge about the topic. So do excuse me if somehow I mess it up. Question: Let's say I have class A,B,C and D now class A has some piece of code which I need to have in class B,C and D so I am extending class A in class B, class C, and class D Now how can I access the function of class A in other classes, do I need to create an object of class A and than access the function of class A or as am extending A in other classes than I can internally call the function using this parameter. If possible I would really appreciate if someone can explain this concept with code sample explaining how the logic flows. Note Example in Java, PHP and .Net would be appreciated.

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• Object Oriented PHP Best Practices

  - by user270797

  Say I have a class which represents a person, a variable within that class would be $name. Previously, In my scripts I would create an instance of the object then set the name by just using: $object->name = "x"; However, I was told this was not best practice? That I should have a function set_name() or something similar like this: function set_name($name) { $this->name=$name; } is this correct? If in this example I want to insert a new "person" record into the db, how do I pass all the information about the person ie $name, $age, $address, $phone etc to the class in order to insert it, should I do: function set($data) { $this->name= $data['name']; $this->age = $data['age']; etc etc } Then send it an array? Would this be best practice? or could someone please recommend best practice?

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• ASP.NET MVC 2 JQuery POST not displaying the model state errors

  - by Oshan

  Hello, I have been using asp.net mvc for a bit (but I'm still a beginer). I want to have the ability to update two views as a result of a jquery postback. Basically I have a list and a details view. The details view is presented using a jquery popup (using jquery-UI popup). I only want to update the list if the details save is successful (i.e. there are no validation errors on the details view). However, if there are any validation errros in the details view, I want to update the details view so that the user sees the validation errors. so I thought in my controller, I return a JsonResult instead of a View. [HttpPost] public ActionResult SavePersonInfo(Person p) { if(ModelState.Valid) { return View("PersonList"); } return Json({Error = true, View = PartialView("PersonDetails", p)}); } As you can see if there are no errors I return the person list view, but if there are any validation errors, I have return the details view. The reason that I'm returning a JsonResult is I need to tell my view there is an error so that the view (jquery) knows which section to update (as in whether to update the person list 'div' or the popup dialog 'div'). So, in my view, the jquery is as follows (please assume that there is a form for entering in the person details and "SubmitPersonForm();" function is called upon clicking on the "Save" button): <script type="text/javascript> $('#btnSave').click(function (event) { onBegin(); $.ajax( { type: "POST", url: "/Person/Save", data: $('form').serialize(), success: function (result) { if(result.Error) { $('#dvDetails').html($(result).View)); } else { $('#dvPersonList').html($result); } } }); }); </script> So the problem that I have now, is that when there is a validation error, I do see the correct, 'div' being updated, but I lose the asp.net mvc validation messages. I do not see any validation errors in red, as if ASP.NET MVC is completely ignored them. However, my ModelState does have those errros, just not displayed in the details view. I do have valication summary and Html.ValidationFor(m = ...) statements put in my details view. Could someone tell me why I'm not seeing the validation errors? although I'm using a JSonResult, I do use the right property which is a valid view when I render the 'dvDetails'. Am I doing something that I'm not suppose to in asp.net mvc? Btw I'm using asp.net mvc2 RC with Visual Studio 2010 RC. Thank you.

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• WPF: Apply ScrollBar Style to ListBox Template - Error object cannot be added to border

  - by TheMar

  Hi, I thought this may be straightforward question but did not find any definitive answer while searching net or SO. I have created scrollbar style (using standard scroll bard template - Blend 2) I am not sure how to apply this style "MyScrollStyle" to a ListBox Template . I saw on ListBox template they have Scroll Viewer -- which should contain the scrollbar Assuming it is something simple as ---Content Added--- After going through lot of xaml in template edit I kind of understood how to apply style. I am trying to add the scroll view style set in this example -http://blog.xamltemplates.net/wp-content/uploads/2008/12/scrollviewer.zip, to my list view template but it gives error -- System.Windows.Markup.XamlParseException was unhandled Message="'ScrollViewer' object cannot be added to 'Border'. Exception has been thrown by the target of an invocation. Error at object 'System.Windows.Controls.ScrollViewer' in markup file 'MenuModule, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null;component/resources/Resources.xaml' Line 19 Position 26." Source="PresentationFramework" LineNumber=19 LinePosition=26 NameContext="1_T" Any help is appreciated Thank you, The Mar

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• Difference between the Repository Pattern and the View Model Pattern

  - by Mark Sayewich

  I am trying to create a site using the ASP MVC Framework. Some of the documentation use the IRepository pattern to abstract the information being sent to the view for rendering, while others recommend using a ViewModel (as in MVVC). What is the difference? Aren't these the same concept? Thanks in advance

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• heroku corrupted object, git fsck fails in rails

  - by Ryan Max

  Hello. I am trying to push an app to heroku and I am getting the error detailed here. So I am trying to determine the corrupt objects using git fsck -full but it isn't returning anything. Nothing happens: Ryan@Ryan-PC ~ $ git fsck --full Ryan@Ryan-PC But I get the object error when I try to push the object to heroku. Is there anyway I can go about repairing the corrupt repository, or can I just delete it and start over? How do I go about doing this?

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• Unable to cast object of type 'System.Data.DataRowView' to type 'System.Data.DataRow'

  - by Asim Sajjad

  I have following exception in the foreach loop Unable to cast object of type 'System.Data.DataRowView' to type 'System.Data.DataRow' how to solve the issue thanks in advance

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• Using 32bit COM object from C# or VBS on Vista 64bit and getting error 80004005

  - by alexandroid

  I need some mind reading here, since I am trying to do what I do not completely understand. There is a 32-bit application (electronic trading application called CQG) which provides a COM API for external access. I have sample programs and scripts which access this API from Excel, .NET (C++, VB and C#) and shell VBScript. I have these .NET applications as source code and as compiled executables (32-bit, compiled on Windows XP). Now I have Windows Vista Home 64-bit which makes my head to spin. Excel examples work just fine (in Excel 2003). Compiled .NET sample executables work as well. But when I am trying to run .NET C# sample converted to and compiled by Visual Studio C# Expression, or run the VBScript script, I am getting error 80004005 when trying to create an object. Initially the .NET application also gave me 80040154 but then I figured how to make it produce 32-bit code and not 64-bit, so now the errors in C# and VBScript applications are the same. That's all the progress I got for now. And yes, I tried running 32-bit versions of cscript.exe/WScript from SysWOW64 folder on my VBS, but still the result is the same (80004005). How to solve this problem? I am almost ready to believe it is practically impossible, but the fact that Excel VBA works and .NET executables compiled on Windows XP run just fine just makes me angry. There should be a way to beat this thing (some secret which probably only Windows Vista developers know)! I will appreciate any help! PS: I believe code samples do not make much sense here, but this is the line of VBScript which fails: Set CEL = WScript.CreateObject("CQG.CQGCEL.4.0", "CEL_") And this is C#: CQGCEL CEL = new CQGCEL(); Update: Forgot to say UAC is off, of course. And I am working from account with administrator priviledges. I also tried watching which registry keys are read using Process Monitor but everything looks OK for GUIDs of this object. I could not recognize some other GUIDs so I am not sure whether they were critical or not. Is there a chance that this COM object uses Internet Explorer and gets the wrong one (like Internet Explorer 7 instead of Internet Explorer 6 engine or something)?

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• Django Admin: Detect if a subset of an object fields has changed and which of them

  - by Mandx

  I need to detect when some of the fields of certain model have changed in the admin, to later send notifications depending on which fields changed and previous/current values of those fields. I tried using a ModelForm and overriding the save() method, but the form's self.cleaned_data and seld.instance already have the new values of the fields.

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• wpf toolkit (Feb 2010) datagrid with MVVM - style reveals name of view model on 'spare column'

  - by Andy Clarke

  Hi, I've just updated my app with the latest WPF toolkit and I've now got an issue with my styling. When I bind some data with, for example, two columns to the grid, the spare area at the right shows the name of the ViewModel in the header. I can understand why, because the data grids data context is the ViewModel and I'm defining my header style as follows ... <WpfToolkit:DataGridHeaderBorder <Border BorderBrush="Blue" BorderThickness="0,1,0,0"> <TextBlock Text="{Binding}" Margin="4,0,4,0" /> </Border> </WpfToolkit:DataGridHeaderBorder> Do I now need a separate style for the 'spare column' or something? Can anyone assist please? Cheers, Andy

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• How to Deserialize XMLDocument to object in C#?

  - by Deepfreezed

  I have a .Net webserivce that accepts XML in string format. XML String sent into the webserivce can represent any Object in the system. I need to check the first node to figure out what object to deserialize the XML string. For this I will have to load the XML into an XMLDocument (Don't want to use RegEx or string compare). I am wondering if there is a way to Deserialize the XMLDocument/XMLNode rather that deserializing the string to save some performance? Is there going to be any performance benefit serializing the XMLNode rather that the string? Method to Load XMLDocument public void LoadFromString(String s) { m_XmlDoc = new XmlDocument(); m_XmlDoc.LoadXml(s); } Thanks

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• Django admin, hide a model

  - by Hellnar

  Hello At the root page of the admin site where registered models appear, I want to hide several models that are registered to the Django admin. If I directly unregister those, I am not able to add new records as the add new symbol "+" dissapears. How can this be done ?

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• Generate a form from an untyped mvc 2 model or dictionary

  - by user329251

  HI all, I am looking for a way to generate and validate mvc 2 forms using untyped entities. Basically similar how the propertygrid in winforms behaves. In the utmost basic sample for instance have an dictionary and generate a form from that depending on the datatype in the Dictionary ofcourse it should be able to fill the same dictionary in the controller. Any ideas or leads or hints? Best regards, Emile

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• Getting the Image Source from an HTMLImageElement object

  - by corymathews

  I have the following jQuery which I want to output a list of images. The problem is that I cannot get 'this' to find the source. It currently is an object which outputs as an HTMLImageElement. How can I get the image source from this object? $("#imgs li.images img").each(function(i) { $("#list").append("<li><img src=\""+this.attr("src")+"\" /></li>"); }); I currently get the error that this.attr is not a function.

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• Making an svg image object clickable with onclick, avoiding absolute positioning

  - by user256410

  I have tried to change the images on my site from to svg, changing img tags to embed and object tags(standard procedure, i think). But, implementing the onclick function, which previously was contained in the img tag is proving most difficult. I found onclick had no effect when placed inside the object or embed tag. So, I made a div exclusively for the svg, and placed onclick in this div tag. But, no effect unless visitor clicks on the edges/padding of the image. I have read about overlaying a div, but am trying to avoid using absolute positioning, or specifying positions at all. Maybe there's a way to do it without specifying postions? Or maybe theres another way to apply onclick to a svg. Has anyone encountered this problem? Questions and suggestions are welcome.

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• Actionscript/Flex - Is it possible to dynamically extend an object, modify functions, add functions

  - by RR

  I know this question might be frowned upon, but actionscript is a dynamic language similar to javascript and in javascript I can take an object from a library written by someone else and dynamically (at runtime) add/remove/modify functions, properties, prototypes etc. this is kind of like dynamically extending an object to make it work with the library it came with as well as another library. Is something like this possible in flex actionscript? I'm thinking it is only possible with classes that are declared 'dynamic' and definitely not possible with classes declared 'final'. What are your thoughts? Any ideas/tricks?

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• Open source licensing and the Red Hat business model

  - by James P.

  How can licenses be applied to have two parallel versions of software, one freely available and another commercial, like Red Hat has done with it's version of Linux? Also, can snippets of code be freely ported from one to the other or must it be designed separately?

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