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  • JavaScript evolution -- weeding out the confusion [closed]

    - by good_computer
    There was JavaScript v1.3 (I guess) that we all started with. Then there was JavaScript 2.0 that Adobe implemented (ActionScript) but was abandoned later. Then came E4X. Then ES5. There is also ES harmony. I am really confused about which version is the latest and where is the standards body going. Can someone describe the whole chronology of JavaScript / ECMAScript evolution and the important differences between those versions?

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  • How do I create my own programming language and a compiler for it

    - by Dave
    I am thorough with programming and have come across languages including BASIC, FORTRAN, COBOL, LISP, LOGO, Java, C++, C, MATLAB, Mathematica, Python, Ruby, Perl, JavaScript, Assembly and so on. I can't understand how people create programming languages and devise compilers for it. I also couldn't understand how people create OS like Windows, Mac, UNIX, DOS and so on. The other thing that is mysterious to me is how people create libraries like OpenGL, OpenCL, OpenCV, Cocoa, MFC and so on. The last thing I am unable to figure out is how scientists devise an assembly language and an assembler for a microprocessor. I would really like to learn all of these stuff and I am 15 years old. I always wanted to be a computer scientist someone like Babbage, Turing, Shannon, or Dennis Ritchie. I have already read Aho's Compiler Design and Tanenbaum's OS concepts book and they all only discuss concepts and code in a high level. They don't go into the details and nuances and how to devise a compiler or operating system. I want a concrete understanding so that I can create one myself and not just an understanding of what a thread, semaphore, process, or parsing is. I asked my brother about all this. He is a SB student in EECS at MIT and hasn't got a clue of how to actually create all these stuff in the real world. All he knows is just an understanding of Compiler Design and OS concepts like the ones that you guys have mentioned (i.e. like Thread, Synchronization, Concurrency, memory management, Lexical Analysis, Intermediate code generation and so on)

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  • Solutions for software using many calls to a server

    - by Val
    I am developing software that uses many calls to a server. On a client side it's a Silverlight application. Almost every time a user clicks on a button in it, it sends 1-5 WCF calls to a server. There can be up to dozen or so users at a time. The server is a database server that serves data to a client. I am an intermediate level developer and am thinking about caching some data and syncing my changes from time to time. Are there any official solutions or technologies for it, like, patterns and such?

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  • How important are unit tests in software development?

    - by Lo Wai Lun
    We are doing software testing by testing a lot of I/O cases, so developers and system analysts can open reviews and test for their committed code within a given time period (e.g. 1 week). But when it come across with extracting information from a database, how to consider the cases and the corresponding methodology to start with? Although that is more likely to be a case studies because the unit-testing depends on the project we have involved which is too specific and particular most of the time. What is the general overview of the steps and precautions for unit-testing?

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  • How do you update live web sites with code changes?

    - by Aaron Anodide
    I know this is a very basic question. If someone could humor me and tell me how they would handle this, I'd be greatful. I decided to post this because I am about to install SynchToy to remedy the issue below, and I feel a bit unprofessional using a "Toy" but I can't think of a better way. Many times I find when I am in this situation, I am missing some painfully obvious way to do things - this comes from being the only developer in the company. ASP.NET web application developed on my computer at work Solution has 2 projects: Website (files) WebsiteLib (C#/dll) Using a Git repository Deployed on a GoGrid 2008R2 web server Deployment: Make code changes. Push to Git. Remote desktop to server. Pull from Git. Overwrite the live files by dragging/dropping with windows explorer. In Step 5 I delete all the files from the website root.. this can't be a good thing to do. That's why I am about to install SynchToy... UPDATE: THANKS for all the useful responses. I can't pick which one to mark answer - between using a web deployment - it looks like I have several useful suggesitons: Web Project = whole site packaged into a single DLL - downside for me I can't push simple updates - being a lone developer in a company of 50, this remains something that is simpler at times. Pulling straight from SCM into web root of site - i originally didn't do this out of fear that my SCM hidden directory might end up being exposed, but the answers here helped me get over that (although i still don't like having one more thing to worry about forgetting to make sure is still true over time) Using a web farm, and systematically deploying to nodes - this is the ideal solution for zero downtime, which is actually something I care about since the site is essentially a real time revenue source for my company - i might have a hard time convincing them to double the cost of the servers though. -- finally, the re-enforcement of the basic principal that there needs to be a single click deployment for the site OR ELSE THERE SOMETHING WRONG is probably the most useful thing I got out of the answers. UPDATE 2: I thought I come back to this and update with the actual solution that's been in place for many months now and is working perfectly (for my single web server solution). The process I use is: Make code changes Push to Git Remote desktop to server Pull from Git Run the following batch script: cd C:\Users\Administrator %systemroot%\system32\inetsrv\appcmd.exe stop site "/site.name:Default Web Site" robocopy Documents\code\da\1\work\Tree\LendingTreeWebSite1 c:\inetpub\wwwroot /E /XF connectionsconfig Web.config %systemroot%\system32\inetsrv\appcmd.exe start site "/site.name:Default Web Site" As you can see this brings the site down, uses robocopy to intelligently copy the files that have changed then brings the site back up. It typically runs in less than 2 seconds. Since peak traffic on this site is about 2 requests per second, missing 4 requests per site update is acceptable. Sine I've gotten more proficient with Git I've found that the first four steps above being a "manual process" is also acceptable, although I'm sure I could roll the whole thing into a single click if I wanted to. The documentation for AppCmd.exe is here. The documentation for Robocopy is here.

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  • How much effort should you put into a junior developer?

    - by Crazy Eddie
    At what point should one give up? I've tried helping them out by having them shadow me. We agree to break a minute, and then they go missing in action for a while...then just go back to their desk. Even when I know they've done this, part of me feels like I shouldn't have to go get them but that they should be showing interest in learning. Frankly, it's a bunch of time I don't have explaining things as I go when I could just do it. Am I expecting too much to expect that if they want to learn they'll make sure I know they're ready and willing? They go to meetings that they where not told they had to, good, but then sit in the corner and sleep...bad. I don't even know what to do with that. Sometimes I give them something small to do and they do it great, so I give them something just a touch harder and they totally fail, hard. Check in things without testing them. Part of me thinks that maybe I should be spending more time with them but at the same time I don't see a lot of interest and I really, honestly don't have time teaching the same things over and over. Sometimes I get asked questions that are really, really easy to answer if you just do a little bit of your own work trying to find out. Other times I'm not asked anything. I'm sure I could be doing better but honestly...I don't really want to anymore.

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  • Ways to dynamically render a real world 3d environment in Unity3D

    - by Jake M
    Using Unity3D and C# I am attempting to display a 3d version of a real world location. Inside my Unity3D app, the user will specify the GPS coordinates of a location, then my app will have to generate a 3d plane(anything doesn't have to be a plane) of that location. The plane will show a 500 metre by 500 metre 3d snapshot of that location. How would you suggest I achieve this in Unity3D? What methodology would you use to achieve this? NOTE: I understand that this is a very difficult endevour(to render real world locations dynamically in Unity3d) so I expect to perform many actions to achieve this. I just don't know of all the technologies out there and which would be best for my needs For example: Suggested methodology 1: Prompt user to specify GPS coords Use Google earth API and HTTP to programmatically obtain a .khm file describing that location(Not sure if google earth provides that capability does it?) Unzip the .khm so I have the .dae file Convert that file to a .3ds file using ??? third party converter(is there a converter that exists?) Import .3ds into Unity3D at runtime as a plane(is this possible)? Suggested methodology 2: Prompt user to specify GPS coords Use Google earth API and HTTP to programmatically obtain a .khm file describing that location(Not sure if google earth provides that capability does it?) Unzip the .khm so I have the .dae file Parse .dae file using my own C# parser I will write(do you think its possible to write a .dae parser that can parse the .dae into an array of Vector3 that describe the height map of that location?) Dynamically create a plane in Unity3D and populate it with my array/list of Vector3 points(is it possible to create a plane this way?) Maybe I am meant to create a mesh instead of a plane? Can you think of any other ways I could render a real world 3d environment in Unity3D?

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  • Securing credentials passed to web service

    - by Greg Smith
    I'm attempting to design a single sign on system for use in a distributed architecture. Specifically, I must provide a way for a client website (that is, a website on a different domain/server/network) to allow users to register accounts on my central system. So, when the user takes an action on a client website, and that action is deemed to require an account, the client will produce a page (on their site/domain) where the user can register for a new account by providing an email and password. The client must then send this information to a web service, which will register the account and return some session token type value. The client will need to hash the password before sending it across the wire, and the webservice will require https, but this doesn't feel like it's safe enough and I need some advice on how I can implement this in the most secure way possible. A few other bits of relevant information: Ideally we'd prefer not to share any code with the client We've considered just redirecting the user to a secure page on the same server as the webservice, but this is likely to be rejected for non-technical reasons. We almost certainaly need to salt the password before hashing and passing it over, but that requires the client to either a) generate the salt and communicate it to us, or b) come and ask us for the salt - both feel dirty. Any help or advice is most appreciated.

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  • How can I sell a legacy program rewrite to the business?

    - by Wil
    We have a legacy classic ASP application that's been around since 2001. It badly needs to be re-written, but it's working fine from an end user perspective. The reason I feel like a rewrite is necessary is that when we need to update it (which is admittedly not that often) then it takes forever to go through all the spaghetti code and fix problems. Also, adding new features is also a pain since it was architect-ed and coded badly. I've run cost analysis for them on maintenance but they are willing to spend more for the small maintenance jobs than a rewrite. Any suggestions on convincing them otherwise?

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  • What sort of security method is this called (if it has a name)?

    - by loosebruce
    I have thought of a way of securing access to an application interacting with another application. Using this method Application 1 - "What is the sum of 1+1?" Application 2 - "3" Application 1 - "Access granted" Is this method used a lot, does it have a classification in the programming world? The advantages for me of using this is that I do not have to spend more effort implementing security keys/certificates. Any unauthorized machine trying to interpret it would give the correct result and identify itself as untrusted. What sort of weaknesses are there to doing this?

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  • High Usage of RAM by wxPython's GUI and need some advice to reduce it

    - by user67024
    I've recently developed a GUI in wxPython for windows platform. It contains a five tabs, 4 of them are just richTextCtrl boxes and the other one has controls for uploading files, buttons, textctrls, a slider etc.. As I was new to GUI development in Python, I used wxFormBuilder to generate some of the code using a good amount of sizers. So, now the problem is that the GUI starts off with a initial memory of around 40MB which is too much for such a simple application (Or so I think) . Also, when the functions handling the functions use huge lists as the program is for debugging large data logs and identifying the problems in'em implying that I can't afford memory for GUI. So, how can I reduce that start working memory size? Is it a general issue in wxPython? And currently trying use profilers but not sure if it's going to help.

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  • How can I keep current with Python coding style?

    - by vartec
    I've been using Python since version 2.2. I do pick up new language constructs like for example with statement or dictionary/set comprehensions. However, I've realized that even though I'm being consistent with PEP-8, for existing constructs I'm using old style, rather than new style (for example except Exception, e instead of except Exception as e). Is there a resource which would have either most current style guide, or even better a list of changes in Python's coding style?

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  • Restrictive routing best practices for Google App Engine with python?

    - by Aleksandr Makov
    Say I have a simple structure: app = webapp2.WSGIApplication([ (r'/', 'pages.login'), (r'/profile', 'pages.profile'), (r'/dashboard', 'pages.dash'), ], debug=True) Basically all pages require authentication except for the login. If visitor tries to reach a restrictive page and he isn't authorized (or lacks privileges) then he gets redirected to the login view. The question is about the routing design. Should I check the auth and ACL privs in each of the modules (pages.profile and pages.dash from example above), or just pass all requests through the single routing mechanism: app = webapp2.WSGIApplication([ (r'/', 'pages.login'), (r'/.+', 'router') ], debug=True) I'm still quite new to the GAE, but my app requires authentication as well as ACL. I'm aware that there's login directive on the server config level, but I don't know how it works and how I can tight it with my ACL logic and what's worse I cannot estimate time needed to get it running. Besides, it looks only to provide only 2 user groups: admin and user. In any case, that's the configuration I use: handlers: - url: /favicon.ico static_files: static/favicon.ico upload: static/favicon.ico - url: /static/* static_dir: static - url: .* script: main.app secure: always Or I miss something here and ACL can be set in the config file? Thanks.

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  • Suggested HTTP REST status code for 'request limit reached'

    - by Andras Zoltan
    I'm putting together a spec for a REST service, part of which will incorporate the ability to throttle users service-wide and on groups of, or on individual, resources. Equally, time-outs for these would be configurable per resource/group/service. I'm just looking through the HTTP 1.1 spec and trying to decide how I will communicate to a client that a request will not be fulfilled because they've reached their limit. Initially I figured that client code 403 - Forbidden was the one, but this, from the spec: Authorization will not help and the request SHOULD NOT be repeated bothered me. It actually appears that 503 - Service Unavailable is a better one to use - since it allows for the communication of a retry time through the use of the Retry-After header. It's possible that in the future I might look to support 'purchasing' more requests via eCommerce (in which case it would be nice if client code 402 - Payment Required had been finalized!) - but I figure that this could equally be squeezed into a 503 response too. Which do you think I should use? Or is there another I've not considered?

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  • Quickly compute added and removed lines

    - by Philippe Marschall
    I'm trying to compare two text files. I want to compute how many lines were added and removed. Basically what git diff --stat is doing. Bonus points for not having to store the entire file contents in memory. The approach I'm currently having in mind is: read each line of the old file compute a hash (probably MD5 or SHA-1) for each line store the hashes in a set do the same for each line in the new file every hash from the old file set that's missing in the new file set was removed every hash from the new file set that's missing in the old file set was added I'll probably want to exclude empty and all white space lines. There is a small issue with duplicated lines. This can either be solved by additionally storing how often a hash appears or comparing the number of lines in the old and new file and adjust either the added or removed lines so that the numbers add up. Do you see room for improvements or a better approach?

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  • saving and retrieving a text file in java?

    - by user3319432
    import java.sql. ; import java.awt.; import javax.swing.; import java.awt.event.; public class saving extends JFrame implements ActionListener{ JTextField edpno=new JTextField(10); JLabel l0= new JLabel ("EDP Number: "); JComboBox fname = new JComboBox(); JLabel l1= new JLabel("First Name: "); JTextField lname= new JTextField(20); JLabel l2= new JLabel("Last Name: "); // JTextField contno= new JTextField(20); // JLabel l3= new JLabel("Contact Number: "); JComboBox contno = new JComboBox(); JLabel l3 = new JLabel ("Contact Number: "); JButton bOK = new JButton("Save"); JButton bRetrieve = new JButton("Retrieve"); private ImageIcon icon; JPanel C=new JPanel(){ protected void paintComponent(Graphics g){ g.drawImage(icon.getImage(),0,0,null); super.paintComponent(g); } }; public Search Record (){ icon=new ImageIcon("images/canres.png"); C.setOpaque(false); C.setLayout(new GridLayout(5,2,4,4)); setTitle("Search Record"); C.add (l0); C.add (edpno); edpno.addActionListener(this); C.add (l1); C.add (fname); fname.setForeground(Color.BLUE); fname.setFont(new Font(" ", Font.BOLD,15)); C.add (l2); C.add (lname); C.add (l3); C.add (contno); contno.setForeground(Color.BLUE); contno.setFont(new Font(" ", Font.BOLD,15)); C.add(bOK); bOK.addActionListener(this); C.add (bRetrieve); bRetrieve.addActionListener(this); bOK.setBackground(Color.white); bRetrieve.setBackground(Color.white); } public void saverecord(){ try{ //Connect to the Database Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); String path ="jdbc:odbc:;DRIVER=Microsoft Access Driver (*.mdb);DBQ=Database/roomassign.mdb"; String DBPassword =""; String DBUserName =""; Connection con = DriverManager.getConnection(path,"",""); Statement s = con.createStatement(); s.executeQuery("select firstname, Lastname, contact number from name WHERE edpno ='"+edpno.getText()+"'"); ResultSet rs = s.getResultSet(); ResultSetMetaData md = rs.getMetaData(); while(rs.next()) { fname.setSelectedItem(rs.getString(1)); lname.setText(rs.getString(2)); contno.setSelectedItem(rs.getString(3)); // crs.setSelectedItem(rs.getString(4)); } s.close(); con.close(); } catch(Exception Q) { JOptionPane.showMessageDialog(this,Q); } } public void SaveRecord(){ try{ Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); String path = "jdbc:odbc:;DRIVER=Microsoft Access Driver (*.mdb);DBQ=Database/roomassign.mdb"; String DBPassword =""; String DBUsername =""; Connection con = DriverManager.getConnection(path,"",""); Statement s = con.createStatement(); String sql = "UPDATE rooms SET Firstname='"+fname.getSelectedItem()+"',Lastname='"+lname.getText()+"',Contactnumber='"+contno.getSelectedItem()+"' WHERE '"+edpno.getText()+"'=edpno"; s.executeUpdate(sql); JOptionPane.showMessageDialog(this,"New room Record has been successfully saved"); dispose(); s.close(); con.close(); } catch(Exception Mismatch){ JOptionPane.showMessageDialog(this,Mismatch); } } public void actionPerformed (ActionEvent ako){ if (ako.getSource() == bRetrieve){ dispose(); } else if (ako.getSource() == bOK){ SaveRecord(); } } public static void main (String [] awtsave){ new Search(); } }

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  • Last click counts link cookies

    - by user3636031
    I want to fix so my only the last click gets the cookie, here is my script: <script type="text/javascript"> document.write('<scr' + 'ipt type="text/javascript" src="' + document.location.protocol + '//sc.tradetracker.net/public/tradetracker/tracking/?e=dedupe&amp;t=js"></scr' + 'ipt>'); </script> <script type="text/javascript"> // The pixels. var _oPixels = { tradetracker: '<img id="tt" />', tradedoubler: '<img id="td" />', zanox: '<img id="zx" />', awin: '<img id="aw" />' }; // Run the dedupe. _ttDedupe( 'conversion', 'network' ); </script> <noscript> <img id="tt" /> <img id="td" /> <img id="zx" /> <img id="aw" /> </noscript> How can I get this right? Thanks!

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  • What is a better language to use when building a database: Visual C# or Visual Basic (VB.net)? [on hold]

    - by user3413537
    I'm building a GUI and a database which is using SQL as a server (internal database not a web application). Which language is more of a "right tool" when it comes to building a not very structurally complicated database? What are the advantages and disadvantages of Visual C# / VB.net? I've been reading a lot of stuff online and they said that VB.net is not as capable and it doesn't have as much support as Visual C#, and it seems that VB.net is on a decline in terms of popularity.

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  • Proper Method name for XML builder

    - by Wesley
    I think this is the right stack for this. I have a helper class which builds CAML queries (SharePoint XML for getting list items from SQL) There is one method that is flexibly used to build the queries that get all related votes and comments for a social item. I don't want to call it BuildVoteorCommentXML or something long winded like that. Is there a good naming convention for getting all Join/Foreign Key objects from a core object?

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  • ERP/CRM Systems. Desktop Based ? Web based?

    - by Parhs
    Hello guys... I have seen 2-3 ERPs in action. I am wondering what is better. Desktop based application or webbased displayed on a browser. My first expirience was with a web based ERP when i was 14 years old.. It was web based and terribly slow... For most simple task you had to do lots of clicks... no keyboard support ..... Pages took ages to load. Last year i worked for migrating to a newer computer some old terminal based cobol application. The computer that worked till today and still has no problem was from 1993. The user interface ofcourse was textbased.. The speed that guys placed orders was amazing! just typing the name of the customer , then 5-10 keys to add a product to order.... Comparing to this ERP the page for placing orders Link (click sales orders) seems terribly slow to add a product... No keyboard shortcut works to save what you added and generally i believe you need 4 times more time to place an order compared to the text interface... Having to use both mouse and keyboard for this task is BAD and sadistic... So how can tek heck these people ever use a system like that ??? So in the long run desktop application seems the only way... Ofcourse browsers support shortcuts but the way to overide the defaults that browsers uses isnt cross compatible... That is a hudge problem. Finnaly, if we MUST/forced use cloud in near future what about keyboard shortcuts?? I feel confused... I have seen converters of desktop applications to browser applications but are SLOW as hell... The question is what about user friendliness?What kind of application would you use?

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  • "Programming error" exceptions - Is my approach sound?

    - by Medo42
    I am currently trying to improve my use of exceptions, and found the important distinction between exceptions that signify programming errors (e.g. someone passed null as argument, or called a method on an object after it was disposed) and those that signify a failure in the operation that is not the caller's fault (e.g. an I/O exception). As far as I understand, it makes little sense for an immediate caller to actually handle programming error exceptions, he should instead assure that the preconditions are met. Only "outer" exception handlers at task boundaries should catch them, so they can keep the system running if a task fails. In order to ensure that client code can cleanly catch "failure" exceptions without catching error exceptions by mistake, I create my own exception classes for all failure exceptions now, and document them in the methods that throw them. I would make them checked exceptions in Java. Now I have a few questions: Before, I tried to document all exceptions that a method could throw, but that sometimes creates an unwiedly list that needs to be documented in every method up the call chain until you can show that the error won't happen. Instead, I document the preconditions in the summary / parameter descriptions and don't even mention what happens if they are not met. The idea is that people should not try to catch these exceptions explicitly anyway, so there is no need to document their types. Would you agree that this is enough? Going further, do you think all preconditions even need to be documented for every method? For example, calling methods in IDisposable objects after calling Dispose is an error, but since IDisposable is such a widely used interface, can I just assume a programmer will know this? A similar case is with reference type parameters where passing null makes no conceivable sense: Should I document "non-null" anyway? IMO, documentation should only cover things that are not obvious, but I am not sure where "obvious" ends.

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  • Can a NodeJS webserver handle multiple hostnames on the same IP?

    - by Matthew Patrick Cashatt
    I have just begun learning NodeJS and LOVE it so far. I have set up a Linux box to run it and, in learning to use the event-driven model, I am curious if I can use a common IP for multiple domain names. Could I point, for example, www.websiteA.com, www.websiteB.com, and www.websiteC.com all to the same IP (node webserver) and then route to the appropriate source files based on the request? Would this cause certain doom when it came to scaling to any reasonable size?

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  • Storing data for use on Android and Windows Applications

    - by Andy Mepham
    I posted this last night on StackOverflow and was advised to move it over to StackExchange, thank you for taking a moment to look at my question. I'm developing a project proposal for my final year project at University and as I aim to use programming languages I am currently not too familiar with I'm looking for some guidance - I can't include details of my project but hopefully you will understand what I'm after. I'm going to be creating an Android application (in Java) and a Windows Application (in C#) that will ideally access, query and update a remotely hosted Database or set of XML files (this would most likely be over the Internet). I've done some looking around the internet and SQLite seems like a safe-bet for cross-platform manipulation of the database; however I would like to keep the system as lightweight as possible and I'm wondering whether XML files may provide a better alternative? Anyone out there that has experience using SQLite and/or remotely hosted XML for the purposes of Android and/or C# development that could point me in the right direction? If there is an alternative solution other than those I have mentioned I would be interested to hear about them too. Thank you for taking the time to read my question. Edit: The purpose of this application is for a small scale business, the data source would not need to be updated by more than one source but may be view from multiple sources (i.e. through multiple phones and a desktop PC). The database wouldn't be updating masses of data at a time (most likely single rows of a few tables at the most).

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  • Teaching programming (languages) in central/northern Europe

    - by canavanin
    I hope this question is not going to be off-topic; in case you think there'd be a better place to ask it, please let me know. Anyway, I'm currently doing my PhD working in bioinformatics. I would, however, like to turn away from academia eventually and instead go into teaching programming or, preferably, programming languages (e.g. Perl, which feels like my "mother tongue"...) - not as a school teacher, but with a company (in Germany or Scandinavia). It'll take me another one to one and a half years to complete my PhD, so I would like to know how I could/should use that time to raise my chances of getting into the profession I'd be interested in. Are there any Perl certificates I should aim to obtain, for example? In case there's anything that comes to mind when reading this, please let me know. Thanks a lot in advance!

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  • MVC + 3 tier; where ViewModels come into play?

    - by mikhairu
    I'm designing a 3-tiered application using ASP.NET MVC 4. I used the following resources as a reference. CodeProject: MVC + N-tier + Entity Framework Separating data access in ASP.NET MVC I have the following desingn so far. Presentation Layer (PL) (main MVC project, where M of MVC was moved to Data Access Layer): MyProjectName.Main Views/ Controllers/ ... Business Logic Layer (BLL): MyProjectName.BLL ViewModels/ ProjectServices/ ... Data Access Layer (DAL): MyProjectName.DAL Models/ Repositories.EF/ Repositories.Dapper/ ... Now, PL references BLL and BLL references DAL. This way lower layer does not depend on the one above it. In this design PL invokes a service of the BLL. PL can pass a View Model to BLL and BLL can pass a View Model back to PL. Also, BLL invokes DAL layer and DAL layer can return a Model back to BLL. BLL can in turn build a View Model and return it to PL. Up to now this pattern was working for me. However, I've ran into a problem where some of my ViewModels require joins on several entities. In the plain MVC approach, in the controller I used a LINQ query to do joins and then select new MyViewModel(){ ... }. But now, in the DAL I do not have access to where ViewModels are defined (in the BLL). This means I cannot do joins in DAL and return it to BLL. It seems I have to do separate queries in DAL (instead of joins in one query) and BLL would then use the result of these to build a ViewModel. This is very inconvenient, but I don't think I should be exposing DAL to ViewModels. Any ideas how I can solve this dilemma? Thanks.

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