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  • Imperative Programming v/s Declarative Programming v/s Functional Programming

    - by kaleidoscope
    Imperative Programming :: Imperative programming is a programming paradigm that describes computation in terms of statements that change a program state. In much the same way as the imperative mood in natural languages expresses commands to take action, imperative programs define sequences of commands for the computer to perform. The focus is on what steps the computer should take rather than what the computer will do (ex. C, C++, Java). Declarative Programming :: Declarative programming is a programming paradigm that expresses the logic of a computation without describing its control flow. It attempts to minimize or eliminate side effects by describing what the program should accomplish, rather than describing how to go about accomplishing it. The focus is on what the computer should do rather than how it should do it (ex. SQL). A  C# example of declarative v/s. imperative programming is LINQ. With imperative programming, you tell the compiler what you want to happen, step by step. For example, let's start with this collection, and choose the odd numbers: List<int> collection = new List<int> { 1, 2, 3, 4, 5 }; With imperative programming, we'd step through this, and decide what we want: List<int> results = new List<int>(); foreach(var num in collection) {     if (num % 2 != 0)           results.Add(num); } Here’s what we are doing: *Create a result collection *Step through each number in the collection *Check the number, if it's odd, add it to the results With declarative programming, on the other hand, we write the code that describes what you want, but not necessarily how to get it var results = collection.Where( num => num % 2 != 0); Here, we're saying "Give us everything where it's odd", not "Step through the collection. Check this item, if it's odd, add it to a result collection." Functional Programming :: Functional programming is a programming paradigm that treats computation as the evaluation of mathematical functions and avoids state and mutable data. It emphasizes the application of functions.Functional programming has its roots in the lambda calculus. It is a subset of declarative languages that has heavy focus on recursion. Functional programming can be a mind-bender, which is one reason why Lisp, Scheme, and Haskell have never really surpassed C, C++, Java and COBOL in commercial popularity. But there are benefits to the functional way. For one, if you can get the logic correct, functional programming requires orders of magnitude less code than imperative programming. That means fewer points of failure, less code to test, and a more productive (and, many would say, happier) programming life. As systems get bigger, this has become more and more important. To know more : http://stackoverflow.com/questions/602444/what-is-functional-declarative-and-imperative-programming http://msdn.microsoft.com/en-us/library/bb669144.aspx http://en.wikipedia.org/wiki/Imperative_programming   Technorati Tags: Ranjit,Imperative Programming,Declarative programming,Functional Programming

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  • Dynamic Paging and Sorting

    - by Ricardo Peres
    Since .NET 3.5 brought us LINQ and expressions, I became a great fan of these technologies. There are times, however, when strong typing cannot be used - for example, when you are developing an ObjectDataSource and you need to do paging having just a column name, a page index and a page size, so I set out to fix this. Yes, I know about Dynamic LINQ, and even talked on it previously, but there's no need to add this extra assembly. So, without further delay, here's the code, in both generic and non-generic versions: public static IList ApplyPagingAndSorting(IEnumerable enumerable, Type elementType, Int32 pageSize, Int32 pageIndex, params String [] orderByColumns) { MethodInfo asQueryableMethod = typeof(Queryable).GetMethods(BindingFlags.Static | BindingFlags.Public).Where(m = (m.Name == "AsQueryable") && (m.ContainsGenericParameters == false)).Single(); IQueryable query = (enumerable is IQueryable) ? (enumerable as IQueryable) : asQueryableMethod.Invoke(null, new Object [] { enumerable }) as IQueryable; if ((orderByColumns != null) && (orderByColumns.Length 0)) { PropertyInfo orderByProperty = elementType.GetProperty(orderByColumns [ 0 ]); MemberExpression member = Expression.MakeMemberAccess(Expression.Parameter(elementType, "n"), orderByProperty); LambdaExpression orderBy = Expression.Lambda(member, member.Expression as ParameterExpression); MethodInfo orderByMethod = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = m.Name == "OrderBy").ToArray() [ 0 ].MakeGenericMethod(elementType, orderByProperty.PropertyType); query = orderByMethod.Invoke(null, new Object [] { query, orderBy }) as IQueryable; if (orderByColumns.Length 1) { MethodInfo thenByMethod = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = m.Name == "ThenBy").ToArray() [ 0 ].MakeGenericMethod(elementType, orderByProperty.PropertyType); PropertyInfo thenByProperty = null; MemberExpression thenByMember = null; LambdaExpression thenBy = null; for (Int32 i = 1; i 0) { MethodInfo takeMethod = typeof(Queryable).GetMethod("Take", BindingFlags.Public | BindingFlags.Static).MakeGenericMethod(elementType); MethodInfo skipMethod = typeof(Queryable).GetMethod("Skip", BindingFlags.Public | BindingFlags.Static).MakeGenericMethod(elementType); query = skipMethod.Invoke(null, new Object [] { query, pageSize * pageIndex }) as IQueryable; query = takeMethod.Invoke(null, new Object [] { query, pageSize }) as IQueryable; } MethodInfo toListMethod = typeof(Enumerable).GetMethod("ToList", BindingFlags.Static | BindingFlags.Public).MakeGenericMethod(elementType); IList list = toListMethod.Invoke(null, new Object [] { query }) as IList; return (list); } public static List ApplyPagingAndSorting(IEnumerable enumerable, Int32 pageSize, Int32 pageIndex, params String [] orderByColumns) { return (ApplyPagingAndSorting(enumerable, typeof(T), pageSize, pageIndex, orderByColumns) as List); } List list = new List { new DateTime(2010, 1, 1), new DateTime(1999, 1, 12), new DateTime(1900, 10, 10), new DateTime(1900, 2, 20), new DateTime(2012, 5, 5), new DateTime(2012, 1, 20) }; List sortedList = ApplyPagingAndSorting(list, 3, 0, "Year", "Month", "Day"); SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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  • JCP.Next - Early Adopters of JCP 2.8

    - by Heather VanCura
    JCP.Next is a series of three JSRs (JSR 348, JSR 355 and JSR 358), to be defined through the JCP process itself, with the JCP Executive Committee serving as the Expert Group. The proposed JSRs will modify the JCP's processes  - the Process Document and Java Specification Participation Agreement (JSPA) and will apply to all new JSRs for all Java platforms.   The first - JCP.next.1, or more formally JSR 348, Towards a new version of the Java Community Process - was completed and put into effect in October 2011 as JCP 2.8. This focused on a small number of simple but important changes to make our process more transparent and to enable broader participation. We're already seeing the benefits of these changes as new and existing JSRs adopt the new requirements. The second - JSR 355, Executive Committee Merge, is also Final. You can read the JCP 2.9 Process Document .  As part of the JSR 355 Final Release, the JCP Executive Committee published revisions to the JCP Process Document (version 2.9) and the EC Standing Rules (version 2.2).  The changes went into effect following the 2012 EC Elections in November. The third JSR 358, A major revision of the Java Community Process was submitted in June 2012.  This JSR will modify the Java Specification Participation Agreement (JSPA) as well as the Process Document, and will tackle a large number of complex issues, many of them postponed from JSR 348. For these reasons, the JCP EC (acting as the Expert Group for this JSR), expects to spend a considerable amount of time working on. The JSPA is defined by the JCP as "a one-year, renewable agreement between the Member and Oracle. The success of the Java community depends upon an open and transparent JCP program.  JSR 358, A major revision of the Java Community Process, is now in process and can be followed on java.net. The following JSRs and Spec Leads were the early adopters of JCP 2.8, who voluntarily migrated their JSRs from JCP 2.x to JCP 2.8 or above.  More candidates for 2012 JCP Star Spec Leads! JSR 236, Concurrency Utilities for Java EE (Anthony Lai/Oracle), migrated April 2012 JSR 308, Annotations on Java Types (Michael Ernst, Alex Buckley/Oracle), migrated September 2012 JSR 335, Lambda Expressions for the Java Programming Language (Brian Goetz/Oracle), migrated October 2012 JSR 337, Java SE 8 Release Contents (Mark Reinhold/Oracle) – EG Formation, migrated September 2012 JSR 338, Java Persistence 2.1 (Linda DeMichiel/Oracle), migrated January 2012 JSR 339, JAX-RS 2.0: The Java API for RESTful Web Services (Santiago Pericas-Geertsen, Marek Potociar/Oracle), migrated July 2012 JSR 340, Java Servlet 3.1 Specification (Shing Wai Chan, Rajiv Mordani/Oracle), migrated August 2012 JSR 341, Expression Language 3.0 (Kin-man Chung/Oracle), migrated August 2012 JSR 343, Java Message Service 2.0 (Nigel Deakin/Oracle), migrated March 2012 JSR 344, JavaServer Faces 2.2 (Ed Burns/Oracle), migrated September 2012 JSR 345, Enterprise JavaBeans 3.2 (Marina Vatkina/Oracle), migrated February 2012 JSR 346, Contexts and Dependency Injection for Java EE 1.1 (Pete Muir/RedHat) – migrated December 2011

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  • How To: Automatically Remove www from a Domain in IIS7

    I recently moved the DevMavens.com site from one server to another and needed to ensure that the www.devmavens.com domain correctly redirected to simply devmavens.com.  This is important for SEO reasons (you dont want multiple domains to refer to the same content) and its generally better to use the shorter URL (www is so 20th century) rather than wasting 4 characters for zero gain. My friend and IIS guru Scott Forsyth pointed me to his blog post on how to set up IIS URL Rewriting.  To get started, you simply install IIS Rewrite from this link using the super awesome Web Platform Installer.  You should get something like this when youre done with the install: If you already have IIS Manager open, you may need to close it and re-open it before you see the URL Rewrite module.  Once you do, you should see it listed for any given Site under the IIS section: Double click on the URL Rewrite icon, and then choose the Add Rule(s) action.  You can simply create a blank rule, and name it Redirect from www to domain.com.  Essentially were following the instructions from Scott Forsyths post, but in reverse since hes showing how to add 4 useless characters to the URL and Im interested in removing them. After adding the name, well set the Match Url sections Using dropdown to Wildcards and specify a pattern of simply * to match anything. In the Conditions section we need to add a new condition with an Input of {HTTP_HOST} such that it should match the pattern www.devmavens.com (replace this with your domain). Ignore the Server Variables section. Set the action to Redirect and the Redirect URL to http://devmavens.com/{R:0} (replace with your domain).  The {R:0} will be replaced with whatever the user had entered.  So if they were going to http://www.devmavens.com/default.aspx theyll now be going to http://devmavens.com/default.aspx. The complete Inbound Rule should look like this: Thats it!  Test it out and make sure you havent accidentally used my exact URLs and started sending all of your users to devmavens.com! :)  Be sure to read Scotts post for more information on how to use regular expressions for your rules, and how to set them up via web.config rather than IIS manager. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Oracle Tutor: Are Documented Policies and Procedures Necessary?

    - by emily.chorba(at)oracle.com
    People refer to policies and procedures with a variety of expressions including business process documentation, standard operating procedures (SOPs), department operating procedures (DOPs), work instructions, specifications, and so on. For our purpose here, policies and procedures mean a set of documents that describe an organization's policies (rules) for operation and the procedures (containing tasks performed by individuals) to fulfill the policies. When an organization documents policies and procedures properly, they can be the strategic link between an organization's vision and its daily operations. Policies and procedures are often necessary because of some external requirement, such as environmental compliance or other governmental regulations. One example of an external requirement would be the American Sarbanes-Oxley Act, requiring full openness in accounting practices. Here are a few other examples of business issues that necessitate writing policies and procedures: Operational needs -- policies and procedures ensure fundamental processes are performed in a consistent way that meets the organization's needs. Risk management -- policies and procedures are identified by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) as a control activity needed to manage risk. Continuous improvement -- Procedures can improve processes by building important internal communication practices. Compliance -- Well-defined and documented processes (i.e. procedures, training materials) along with records that demonstrate process capability can demonstrate an effective internal control system compliant with regulations and standards. In addition to helping with the above business issues, policies and procedures can support the basic needs of employees and management. Well documented and easy to access policies and procedures: allow employees to understand their roles and responsibilities within predefined limits and to stay on the accepted path indentified by the organization's management provide clarity to the reader when dealing with accountability issues or activities that are of critical importance allow management to guide operations without constant intervention allow managers to control events in advance and prevent employees from making costly mistakes Can you think of another way organizations can meet the above needs of management and their employees in place of documented Policies and Procedures? Probably not, but we would love your feedback on this question. And that my friends, is why documented policies and procedures are very necessary. Learn MoreFor more information about Tutor, visit Oracle.com or the Tutor Blog. Post your questions at the Tutor Forum. Emily ChorbaPrinciple Product Manager Oracle Tutor & BPM

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  • SQL SERVER – Saturday Fun Puzzle with SQL Server DATETIME2 and CAST

    - by pinaldave
    Note: I have used SQL Server 2012 for this small fun experiment. Here is what we are going to do. We will run the script one at time instead of running them all together and try to guess the answer. I am confident that many will get it correct but if you do not get correct, you learn something new. Let us create database and sample table. CREATE DATABASE DB2012 GO USE DB2012 GO CREATE TABLE TableDT (DT1 VARCHAR(100), DT2 DATETIME2, DT1C AS DT1, DT2C AS DT2); INSERT INTO TableDT (DT1, DT2) SELECT GETDATE(), GETDATE() GO There are four columns in the table. The first column DT1 is regular VARCHAR and second DT2 is DATETIME2. Both of the column are been populated with the same data as I have used the function GETDATE(). Now let us do the SELECT statement and get the result from both the columns. Before running the query please guess the answer and write it down on the paper or notepad. Question 1: Guess the resultset SELECT DT1, DT2 FROM TableDT GO Now once again run the select statement on the same table but this time retrieve the computed columns only. Once again I suggest you write down the result on the notepad. Question 2: Guess the resultset SELECT DT1C, DT2C FROM TableDT GO Now here is the best part. Let us use the CAST function over the computed columns. Here I do want you to stop and guess the answer for sure. If you have not done it so far, stop do it, believe me you will like it. Question 3: Guess the resultset SELECT CAST(DT1C AS DATETIME2) CDT1C, CAST(DT2C AS DATETIME2) CDT1C FROM TableDT GO Now let us inspect all the answers together and see how many of you got it correct. Answer 1: Answer 2: Answer 3:  If you have not tried to run the script so far, you can execute all the three of the above script together over here and see the result together. SELECT CAST(DT1C AS DATETIME2) CDT1C, CAST(DT2C AS DATETIME2) CDT1C FROM TableDT GO Here is the Saturday Fun question to you – why do we get same result from both of the expressions in Question 3, where as in question 2 both the expression have different answer. I will publish the valid answer with explanation in future blog posts. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DateTime, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Silverlight Cream for April 08, 2010 -- #834

    - by Dave Campbell
    In this Issue: Michael Washington, Phil Middlemiss, Yochay Kiriaty, Giorgetti Alessandro, Mike Snow, John Papa, SilverLaw, smartyP, and Pete Brown. Shoutouts: Steve Wortham sent me a link to his RegEx tool that is written in Silverlight... definitely worth a look: Introducing Code Hinting for Regular Expressions Joshua Blake posted his MIX10 materials: MIX10 NUI session sample code From SilverlightCream.com: Silverlight MVVM: An (Overly) Simplified Explanation Michael Washington has a tutorial up for getting your arms (and head) around MVVM and Silverlight, and Blend too. A Chrome and Glass Theme - Part 3 Phil Middlemiss has part 3 up of his tutorial series on building an awesome theme for Silverlight... he's styling the textbox and checkbox this time around, and improving the button too Automatic Rotation Support or Automatic Multi-Orientation Layout Support for Windows Phone Yochay Kiriaty is giving up some WP7 goodness with his post on Multi-Orientation Layout Support ... yeah I had to say it twice myself :) good links and all the code in addition to the good blog post Silverlight Navigation Framework: resolve the pages using an IoC container Giorgetti Alessandro has some pretty cool code up as a proof of concept of using an IoC container with the Navigation Framework of Silverlight 4. Silverlight Tip of the Day No. 109 – Attach to Process Debugging Mike Snow is back doing Tips of the Day... and number 109 is showing how to attach the debugger to a running Silverlight app. Silverlight TV 20: Community Driven Development with WCF RIA Services In his latest Silverlight TV episode, John Papa talks with Jeff Handley about RIA Services, and how feedback from the community helped shape the product. ChildWindowMouseScrollResizeBehavior - Silverlight 3 SilverLaw has a new Behavior up at the Expression Gallery that gives you resizing on a ChildWindow using the Mouse Wheel. Creating a Windows Phone 7 Metro Style Pivot Application [Part 3] smartyP has the 3rd and final episode for his WP7 Pivot up, and this one includes not only the source but a video tutorial. Layout Rounding Pete Brown talks about Layout Rounding and it has nothing to do with rounding corners... it has to do with rounding off where your objects get placed pixel-wise ... I've blogged about this seemingly-anti-aliasing more than once... Pete has the real answer Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • SQL SERVER – Solution – 2 T-SQL Puzzles – Display Star and Shortest Code to Display 1

    - by pinaldave
    Earlier on this blog we had asked two puzzles. The response from all of you is nothing but Amazing. I have received 350+ responses. Many are valid and many were indeed something I had not thought about it. I strongly suggest you read all the puzzles and their answers here - trust me if you start reading the comments you will not stop till you read every single comment. Seriously trust me on it. Personally I have learned a lot from it. Let us recap the puzzles here quickly. Puzzle 1: Why following code when executed in SSMS displays result as a * (Star)? SELECT CAST(634 AS VARCHAR(2)) Puzzle 2: Write the shortest code that produces results as 1 without using any numbers in the select statement. Bonus Q: How many different Operating System (OS) NuoDB support? As I mentioned earlier the participation was nothing but Amazing. I will write about the winners and the best answers in short time. Meanwhile I will give to the point answers to above puzzles. Solution 1: When you convert character or binary expressions (char, nchar, nvarchar, varchar,binary, or varbinary) to an expression of a different data type, data can be truncated, only partially displayed, or an error is returned because the result is too short to display. Conversions to char, varchar, nchar, nvarchar, binary, and varbinary are truncated, except for the conversions shown in the following table. Reference of the text and table from MSDN. Solution 2: The shortest code to produce answer 1 : SELECT EXP($) or SELECT COS($) or SELECT DAY($) When SELECT $ it gives us the result as 0.00 and the EXP of the same is 1. I believe it is pretty neat. There were plenty other answers but this was the shortest. Another shorter answer would be PRINT EXP($) but no one has proposed that as in original Question I have explicitly mentioned SELECT in the original question. Bonus Answer: 5 OS: Windows, MacOS, Linux, Solaris, Joyent SmartOS Reference Please do read every single comment here. Do leave a comment which one do you think is the best comment out of all the comments. Meanwhile if there is a better solution and I have missed it do let me know as we still have time to correct it. I will be selecting the winner before the weekend as I am going through each and every of 350 comment. I will be selecting the best comments along with the winning comment. If our selection matches – one of you may still win something cool.  Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology Tagged: NuoDB

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  • Dynamic Filtering

    - by Ricardo Peres
    Continuing my previous posts on dynamic LINQ, now it's time for dynamic filtering. For now, I'll focus on string matching. There are three standard operators for string matching, which both NHibernate, Entity Framework and LINQ to SQL recognize: Equals Contains StartsWith EndsWith So, if we want to apply filtering by one of these operators on a string property, we can use this code: public enum MatchType { StartsWith = 0, EndsWith = 1, Contains = 2, Equals = 3 } public static List Filter(IEnumerable enumerable, String propertyName, String filter, MatchType matchType) { return (Filter(enumerable, typeof(T), propertyName, filter, matchType) as List); } public static IList Filter(IEnumerable enumerable, Type elementType, String propertyName, String filter, MatchType matchType) { MethodInfo asQueryableMethod = typeof(Queryable).GetMethods(BindingFlags.Static | BindingFlags.Public).Where(m = (m.Name == "AsQueryable") && (m.ContainsGenericParameters == false)).Single(); IQueryable query = (enumerable is IQueryable) ? (enumerable as IQueryable) : asQueryableMethod.Invoke(null, new Object [] { enumerable }) as IQueryable; MethodInfo whereMethod = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = m.Name == "Where").ToArray() [ 0 ].MakeGenericMethod(elementType); MethodInfo matchMethod = typeof(String).GetMethod ( (matchType == MatchType.StartsWith) ? "StartsWith" : (matchType == MatchType.EndsWith) ? "EndsWith" : (matchType == MatchType.Contains) ? "Contains" : "Equals", new Type [] { typeof(String) } ); PropertyInfo displayProperty = elementType.GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance); MemberExpression member = Expression.MakeMemberAccess(Expression.Parameter(elementType, "n"), displayProperty); MethodCallExpression call = Expression.Call(member, matchMethod, Expression.Constant(filter)); LambdaExpression where = Expression.Lambda(call, member.Expression as ParameterExpression); query = whereMethod.Invoke(null, new Object [] { query, where }) as IQueryable; MethodInfo toListMethod = typeof(Enumerable).GetMethod("ToList", BindingFlags.Static | BindingFlags.Public).MakeGenericMethod(elementType); IList list = toListMethod.Invoke(null, new Object [] { query }) as IList; return (list); } var list = new [] { new { A = "aa" }, new { A = "aabb" }, new { A = "ccaa" }, new { A = "ddaadd" } }; var contains = Filter(list, "A", "aa", MatchType.Contains); var endsWith = Filter(list, "A", "aa", MatchType.EndsWith); var startsWith = Filter(list, "A", "aa", MatchType.StartsWith); var equals = Filter(list, "A", "aa", MatchType.Equals); Perhaps I'll write some more posts on this subject in the near future. SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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  • SQL Saturday #162 Cambridge

    - by Most Valuable Yak (Rob Volk)
    Despite the efforts of American Airlines, this past weekend I attended the first SQL Saturday in the UK!  Hosted by the SQLCambs Chapter of PASS and organized by Mark (b|t) & Lorraine Broadbent, ably assisted by John Martin (b|t), Mark Pryce-Maher (b|t) and other folks whose names I've unfortunately forgotten, it was held at the Crowne Plaza Hotel, which is completely surrounded by Cambridge University. On Friday, they presented 3 pre-conference sessions given by the brilliant American Cloud & DBA Guru, Buck Woody (b|t), the brilliant Danish SQL Server Internals Guru, Mark Rasmussen (b|t), and the brilliant Scottish Business Intelligence Guru and recent Outstanding Pass Volunteer, Jen Stirrup (b|t).  While I would have loved to attend any of their pre-cons (having seen them present several times already), finances and American Airlines ultimately made that impossible.  But not to worry, I caught up with them during the regular sessions and at the speaker dinner.  And I got back the money they all owed me.  (Actually I owed Mark some money) The schedule was jam-packed even with only 4 tracks, there were 8 regular slots, a lunch session for sponsor presentations, and a 15 minute keynote given by Buck Woody, who besides giving an excellent history of SQL Server at Microsoft (and before), also explained the source of the "unknown contact" image that appears in Outlook.  Hint: it's not Buck himself. Amazingly, and against all better judgment, I even got to present at SQL Saturday 162!  I did a 5 minute Lightning Talk on Regular Expressions in SSMS.  I then did a regular 50 minute session on Constraints.  You can download the content for the regular session at that link, and for the regular expression presentation here. I had a great time and had a great audience for both of my sessions.  You would never have guessed this was the first event for the organizers, everything went very smoothly, especially for the number of attendees and the relative smallness of the space.  The event sponsors also deserve a lot of credit for making themselves fit in a small area and for staying through the entire event until the giveaways at the very end. Overall this was one of the best SQL Saturdays I've ever attended and I have to congratulate Mark B, Lorraine, John, Mark P-M, and all the volunteers and speakers for making this an astoundingly hard act to follow!  Well done!

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  • SSIS Expression Editor & Tester

    Published today on CodePlex is the SSIS Expression Editor & Tester project. If you want to try it just pop over to CodePlex and download it. About five years ago I developed my own expression editor control. It first got used in our custom tasks as the MS editor didn’t become available until SQL 2005 SP1, but even then it had some handy features I preferred. For example resizable panes so that if your expression result was more than two lines you could see them all. It also meant I could change the functions available in the tree view, the most obvious use being to add some handy snippets and samples that I used a lot. This quickly developed into a small expression testing tool. I’d develop complex expressions using my editor and then copy it back into the package itself. I have been meaning to make the tool available for some time and finally made the effort, the code is checked-in and the signed downloads are published on CodePlex. There are two flavours, SQL 2005 or 2008, and just a simple zip file to download and extract. The tool doesn’t need installing, and is completely portable. It does need SSIS to be installed on the local machine though. Each zip file contains two files: ExpressionTester.exe – The tool itself, run this. ExpressionEditor.dll – The reusable editor control. A while ago the gentlemen behind BIDS Helper noticed the editor on a task and asked about using it. This became incorporated into their variable window extensions feature. To try and help them and anyone else that wants to use the editor control, it is available as a single assembly that you can reference yourself, and of course all the source code is on CodePlex too. Just add a reference to the ExpressionEditor.dll assembly and you should be up and running in no time. There is a sample project Package Test in the source code which shows how to use the editor control form in it’s simplest form, or if you want to host control directly then the tester tool is a perfect example.

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  • Using the ASP.NET Cache to cache data in a Model or Business Object layer, without a dependency on System.Web in the layer - Part One.

    - by Rhames
    ASP.NET applications can make use of the System.Web.Caching.Cache object to cache data and prevent repeated expensive calls to a database or other store. However, ideally an application should make use of caching at the point where data is retrieved from the database, which typically is inside a Business Objects or Model layer. One of the key features of using a UI pattern such as Model-View-Presenter (MVP) or Model-View-Controller (MVC) is that the Model and Presenter (or Controller) layers are developed without any knowledge of the UI layer. Introducing a dependency on System.Web into the Model layer would break this independence of the Model from the View. This article gives a solution to this problem, using dependency injection to inject the caching implementation into the Model layer at runtime. This allows caching to be used within the Model layer, without any knowledge of the actual caching mechanism that will be used. Create a sample application to use the caching solution Create a test SQL Server database This solution uses a SQL Server database with the same Sales data used in my previous post on calculating running totals. The advantage of using this data is that it gives nice slow queries that will exaggerate the effect of using caching! To create the data, first create a new SQL database called CacheSample. Next run the following script to create the Sale table and populate it: USE CacheSample GO   CREATE TABLE Sale(DayCount smallint, Sales money) CREATE CLUSTERED INDEX ndx_DayCount ON Sale(DayCount) go INSERT Sale VALUES (1,120) INSERT Sale VALUES (2,60) INSERT Sale VALUES (3,125) INSERT Sale VALUES (4,40)   DECLARE @DayCount smallint, @Sales money SET @DayCount = 5 SET @Sales = 10   WHILE @DayCount < 5000  BEGIN  INSERT Sale VALUES (@DayCount,@Sales)  SET @DayCount = @DayCount + 1  SET @Sales = @Sales + 15  END Next create a stored procedure to calculate the running total, and return a specified number of rows from the Sale table, using the following script: USE [CacheSample] GO   SET ANSI_NULLS ON GO   SET QUOTED_IDENTIFIER ON GO   -- ============================================= -- Author:        Robin -- Create date: -- Description:   -- ============================================= CREATE PROCEDURE [dbo].[spGetRunningTotals]       -- Add the parameters for the stored procedure here       @HighestDayCount smallint = null AS BEGIN       -- SET NOCOUNT ON added to prevent extra result sets from       -- interfering with SELECT statements.       SET NOCOUNT ON;         IF @HighestDayCount IS NULL             SELECT @HighestDayCount = MAX(DayCount) FROM dbo.Sale                   DECLARE @SaleTbl TABLE (DayCount smallint, Sales money, RunningTotal money)         DECLARE @DayCount smallint,                   @Sales money,                   @RunningTotal money         SET @RunningTotal = 0       SET @DayCount = 0         DECLARE rt_cursor CURSOR       FOR       SELECT DayCount, Sales       FROM Sale       ORDER BY DayCount         OPEN rt_cursor         FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales         WHILE @@FETCH_STATUS = 0 AND @DayCount <= @HighestDayCount        BEGIN        SET @RunningTotal = @RunningTotal + @Sales        INSERT @SaleTbl VALUES (@DayCount,@Sales,@RunningTotal)        FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales        END         CLOSE rt_cursor       DEALLOCATE rt_cursor         SELECT DayCount, Sales, RunningTotal       FROM @SaleTbl   END   GO   Create the Sample ASP.NET application In Visual Studio create a new solution and add a class library project called CacheSample.BusinessObjects and an ASP.NET web application called CacheSample.UI. The CacheSample.BusinessObjects project will contain a single class to represent a Sale data item, with all the code to retrieve the sales from the database included in it for simplicity (normally I would at least have a separate Repository or other object that is responsible for retrieving data, and probably a data access layer as well, but for this sample I want to keep it simple). The C# code for the Sale class is shown below: using System; using System.Collections.Generic; using System.Data; using System.Data.SqlClient;   namespace CacheSample.BusinessObjects {     public class Sale     {         public Int16 DayCount { get; set; }         public decimal Sales { get; set; }         public decimal RunningTotal { get; set; }           public static IEnumerable<Sale> GetSales(int? highestDayCount)         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager .ConnectionStrings["CacheSample"].ConnectionString;               using(SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         }     } }   The static GetSale() method makes a call to the spGetRunningTotals stored procedure and then reads each row from the returned SqlDataReader into an instance of the Sale class, it then returns a List of the Sale objects, as IEnnumerable<Sale>. A reference to System.Configuration needs to be added to the CacheSample.BusinessObjects project so that the connection string can be read from the web.config file. In the CacheSample.UI ASP.NET project, create a single web page called ShowSales.aspx, and make this the default start up page. This page will contain a single button to call the GetSales() method and a label to display the results. The html mark up and the C# code behind are shown below: ShowSales.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowSales.aspx.cs" Inherits="CacheSample.UI.ShowSales" %>   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">   <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server">     <title>Cache Sample - Show All Sales</title> </head> <body>     <form id="form1" runat="server">     <div>         <asp:Button ID="btnTest1" runat="server" onclick="btnTest1_Click"             Text="Get All Sales" />         &nbsp;&nbsp;&nbsp;         <asp:Label ID="lblResults" runat="server"></asp:Label>         </div>     </form> </body> </html>   ShowSales.aspx.cs using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls;   using CacheSample.BusinessObjects;   namespace CacheSample.UI {     public partial class ShowSales : System.Web.UI.Page     {         protected void Page_Load(object sender, EventArgs e)         {         }           protected void btnTest1_Click(object sender, EventArgs e)         {             System.Diagnostics.Stopwatch stopWatch = new System.Diagnostics.Stopwatch();             stopWatch.Start();               var sales = Sale.GetSales(null);               var lastSales = sales.Last();               stopWatch.Stop();               lblResults.Text = string.Format( "Count of Sales: {0}, Last DayCount: {1}, Total Sales: {2}. Query took {3} ms", sales.Count(), lastSales.DayCount, lastSales.RunningTotal, stopWatch.ElapsedMilliseconds);         }       } }   Finally we need to add a connection string to the CacheSample SQL Server database, called CacheSample, to the web.config file: <?xmlversion="1.0"?>   <configuration>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   Run the application and click the button a few times to see how long each call to the database takes. On my system, each query takes about 450ms. Next I shall look at a solution to use the ASP.NET caching to cache the data returned by the query, so that subsequent requests to the GetSales() method are much faster. Adding Data Caching Support I am going to create my caching support in a separate project called CacheSample.Caching, so the next step is to add a class library to the solution. We shall be using the application configuration to define the implementation of our caching system, so we need a reference to System.Configuration adding to the project. ICacheProvider<T> Interface The first step in adding caching to our application is to define an interface, called ICacheProvider, in the CacheSample.Caching project, with methods to retrieve any data from the cache or to retrieve the data from the data source if it is not present in the cache. Dependency Injection will then be used to inject an implementation of this interface at runtime, allowing the users of the interface (i.e. the CacheSample.BusinessObjects project) to be completely unaware of how the caching is actually implemented. As data of any type maybe retrieved from the data source, it makes sense to use generics in the interface, with a generic type parameter defining the data type associated with a particular instance of the cache interface implementation. The C# code for the ICacheProvider interface is shown below: using System; using System.Collections.Generic;   namespace CacheSample.Caching {     public interface ICacheProvider     {     }       public interface ICacheProvider<T> : ICacheProvider     {         T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);           IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);     } }   The empty non-generic interface will be used as a type in a Dictionary generic collection later to store instances of the ICacheProvider<T> implementation for reuse, I prefer to use a base interface when doing this, as I think the alternative of using object makes for less clear code. The ICacheProvider<T> interface defines two overloaded Fetch methods, the difference between these is that one will return a single instance of the type T and the other will return an IEnumerable<T>, providing support for easy caching of collections of data items. Both methods will take a key parameter, which will uniquely identify the cached data, a delegate of type Func<T> or Func<IEnumerable<T>> which will provide the code to retrieve the data from the store if it is not present in the cache, and absolute or relative expiry policies to define when a cached item should expire. Note that at present there is no support for cache dependencies, but I shall be showing a method of adding this in part two of this article. CacheProviderFactory Class We need a mechanism of creating instances of our ICacheProvider<T> interface, using Dependency Injection to get the implementation of the interface. To do this we shall create a CacheProviderFactory static class in the CacheSample.Caching project. This factory will provide a generic static method called GetCacheProvider<T>(), which shall return instances of ICacheProvider<T>. We can then call this factory method with the relevant data type (for example the Sale class in the CacheSample.BusinessObject project) to get a instance of ICacheProvider for that type (e.g. call CacheProviderFactory.GetCacheProvider<Sale>() to get the ICacheProvider<Sale> implementation). The C# code for the CacheProviderFactory is shown below: using System; using System.Collections.Generic;   using CacheSample.Caching.Configuration;   namespace CacheSample.Caching {     public static class CacheProviderFactory     {         private static Dictionary<Type, ICacheProvider> cacheProviders = new Dictionary<Type, ICacheProvider>();         private static object syncRoot = new object();           ///<summary>         /// Factory method to create or retrieve an implementation of the  /// ICacheProvider interface for type <typeparamref name="T"/>.         ///</summary>         ///<typeparam name="T">  /// The type that this cache provider instance will work with  ///</typeparam>         ///<returns>An instance of the implementation of ICacheProvider for type  ///<typeparamref name="T"/>, as specified by the application  /// configuration</returns>         public static ICacheProvider<T> GetCacheProvider<T>()         {             ICacheProvider<T> cacheProvider = null;             // Get the Type reference for the type parameter T             Type typeOfT = typeof(T);               // Lock the access to the cacheProviders dictionary             // so multiple threads can work with it             lock (syncRoot)             {                 // First check if an instance of the ICacheProvider implementation  // already exists in the cacheProviders dictionary for the type T                 if (cacheProviders.ContainsKey(typeOfT))                     cacheProvider = (ICacheProvider<T>)cacheProviders[typeOfT];                 else                 {                     // There is not already an instance of the ICacheProvider in       // cacheProviders for the type T                     // so we need to create one                       // Get the Type reference for the application's implementation of       // ICacheProvider from the configuration                     Type cacheProviderType = Type.GetType(CacheProviderConfigurationSection.Current. CacheProviderType);                     if (cacheProviderType != null)                     {                         // Now get a Type reference for the Cache Provider with the                         // type T generic parameter                         Type typeOfCacheProviderTypeForT = cacheProviderType.MakeGenericType(new Type[] { typeOfT });                         if (typeOfCacheProviderTypeForT != null)                         {                             // Create the instance of the Cache Provider and add it to // the cacheProviders dictionary for future use                             cacheProvider = (ICacheProvider<T>)Activator. CreateInstance(typeOfCacheProviderTypeForT);                             cacheProviders.Add(typeOfT, cacheProvider);                         }                     }                 }             }               return cacheProvider;                 }     } }   As this code uses Activator.CreateInstance() to create instances of the ICacheProvider<T> implementation, which is a slow process, the factory class maintains a Dictionary of the previously created instances so that a cache provider needs to be created only once for each type. The type of the implementation of ICacheProvider<T> is read from a custom configuration section in the application configuration file, via the CacheProviderConfigurationSection class, which is described below. CacheProviderConfigurationSection Class The implementation of ICacheProvider<T> will be specified in a custom configuration section in the application’s configuration. To handle this create a folder in the CacheSample.Caching project called Configuration, and add a class called CacheProviderConfigurationSection to this folder. This class will extend the System.Configuration.ConfigurationSection class, and will contain a single string property called CacheProviderType. The C# code for this class is shown below: using System; using System.Configuration;   namespace CacheSample.Caching.Configuration {     internal class CacheProviderConfigurationSection : ConfigurationSection     {         public static CacheProviderConfigurationSection Current         {             get             {                 return (CacheProviderConfigurationSection) ConfigurationManager.GetSection("cacheProvider");             }         }           [ConfigurationProperty("type", IsRequired=true)]         public string CacheProviderType         {             get             {                 return (string)this["type"];             }         }     } }   Adding Data Caching to the Sales Class We now have enough code in place to add caching to the GetSales() method in the CacheSample.BusinessObjects.Sale class, even though we do not yet have an implementation of the ICacheProvider<T> interface. We need to add a reference to the CacheSample.Caching project to CacheSample.BusinessObjects so that we can use the ICacheProvider<T> interface within the GetSales() method. Once the reference is added, we can first create a unique string key based on the method name and the parameter value, so that the same cache key is used for repeated calls to the method with the same parameter values. Then we get an instance of the cache provider for the Sales type, using the CacheProviderFactory, and pass the existing code to retrieve the data from the database as the retrievalMethod delegate in a call to the Cache Provider Fetch() method. The C# code for the modified GetSales() method is shown below: public static IEnumerable<Sale> GetSales(int? highestDayCount) {     string cacheKey = string.Format("CacheSample.BusinessObjects.GetSalesWithCache({0})", highestDayCount);       return CacheSample.Caching.CacheProviderFactory. GetCacheProvider<Sale>().Fetch(cacheKey,         delegate()         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager. ConnectionStrings["CacheSample"].ConnectionString;               using (SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         },         null,         new TimeSpan(0, 10, 0)); }     This example passes the code to retrieve the Sales data from the database to the Cache Provider as an anonymous method, however it could also be written as a lambda. The main advantage of using an anonymous function (method or lambda) is that the code inside the anonymous function can access the parameters passed to the GetSales() method. Finally the absolute expiry is set to null, and the relative expiry set to 10 minutes, to indicate that the cache entry should be removed 10 minutes after the last request for the data. As the ICacheProvider<T> has a Fetch() method that returns IEnumerable<T>, we can simply return the results of the Fetch() method to the caller of the GetSales() method. This should be all that is needed for the GetSales() method to now retrieve data from a cache after the first time the data has be retrieved from the database. Implementing a ASP.NET Cache Provider The final step is to actually implement the ICacheProvider<T> interface, and add the implementation details to the web.config file for the dependency injection. The cache provider implementation needs to have access to System.Web. Therefore it could be placed in the CacheSample.UI project, or in its own project that has a reference to System.Web. Implementing the Cache Provider in a separate project is my favoured approach. Create a new project inside the solution called CacheSample.CacheProvider, and add references to System.Web and CacheSample.Caching to this project. Add a class to the project called AspNetCacheProvider. Make the class a generic class by adding the generic parameter <T> and indicate that the class implements ICacheProvider<T>. The C# code for the AspNetCacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching;   using CacheSample.Caching;   namespace CacheSample.CacheProvider {     public class AspNetCacheProvider<T> : ICacheProvider<T>     {         #region ICacheProvider<T> Members           public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           #endregion           #region Helper Methods           private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             U value;             if (!TryGetValue<U>(key, out value))             {                 value = retrieveData();                 if (!absoluteExpiry.HasValue)                     absoluteExpiry = Cache.NoAbsoluteExpiration;                   if (!relativeExpiry.HasValue)                     relativeExpiry = Cache.NoSlidingExpiration;                   HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value);             }             return value;         }           private bool TryGetValue<U>(string key, out U value)         {             object cachedValue = HttpContext.Current.Cache.Get(key);             if (cachedValue == null)             {                 value = default(U);                 return false;             }             else             {                 try                 {                     value = (U)cachedValue;                     return true;                 }                 catch                 {                     value = default(U);                     return false;                 }             }         }           #endregion       } }   The two interface Fetch() methods call a private method called FetchAndCache(). This method first checks for a element in the HttpContext.Current.Cache with the specified cache key, and if so tries to cast this to the specified type (either T or IEnumerable<T>). If the cached element is found, the FetchAndCache() method simply returns it. If it is not found in the cache, the method calls the retrievalMethod delegate to get the data from the data source, and then adds this to the HttpContext.Current.Cache. The final step is to add the AspNetCacheProvider class to the relevant custom configuration section in the CacheSample.UI.Web.Config file. To do this there needs to be a <configSections> element added as the first element in <configuration>. This will match a custom section called <cacheProvider> with the CacheProviderConfigurationSection. Then we add a <cacheProvider> element, with a type property set to the fully qualified assembly name of the AspNetCacheProvider class, as shown below: <?xmlversion="1.0"?>   <configuration>  <configSections>     <sectionname="cacheProvider" type="CacheSample.Base.Configuration.CacheProviderConfigurationSection, CacheSample.Base" />  </configSections>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <cacheProvidertype="CacheSample.CacheProvider.AspNetCacheProvider`1, CacheSample.CacheProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">  </cacheProvider>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   One point to note is that the fully qualified assembly name of the AspNetCacheProvider class includes the notation `1 after the class name, which indicates that it is a generic class with a single generic type parameter. The CacheSample.UI project needs to have references added to CacheSample.Caching and CacheSample.CacheProvider so that the actual application is aware of the relevant cache provider implementation. Conclusion After implementing this solution, you should have a working cache provider mechanism, that will allow the middle and data access layers to implement caching support when retrieving data, without any knowledge of the actually caching implementation. If the UI is not ASP.NET based, if for example it is Winforms or WPF, the implementation of ICacheProvider<T> would be written around whatever technology is available. It could even be a standalone caching system that takes full responsibility for adding and removing items from a global store. The next part of this article will show how this caching mechanism may be extended to provide support for cache dependencies, such as the System.Web.Caching.SqlCacheDependency. Another possible extension would be to cache the cache provider implementations instead of storing them in a static Dictionary in the CacheProviderFactory. This would prevent a build up of seldom used cache providers in the application memory, as they could be removed from the cache if not used often enough, although in reality there are probably unlikely to be vast numbers of cache provider implementation instances, as most applications do not have a massive number of business object or model types.

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  • Hype and LINQ

    - by Tony Davis
    "Tired of querying in antiquated SQL?" I blinked in astonishment when I saw this headline on the LinqPad site. Warming to its theme, the site suggests that what we need is to "kiss goodbye to SSMS", and instead use LINQ, a modern query language! Elsewhere, there is an article entitled "Why LINQ beats SQL". The designers of LINQ, along with many DBAs, would, I'm sure, cringe with embarrassment at the suggestion that LINQ and SQL are, in any sense, competitive ways of doing the same thing. In fact what LINQ really is, at last, is an efficient, declarative language for C# and VB programmers to access or manipulate data in objects, local data stores, ORMs, web services, data repositories, and, yes, even relational databases. The fact is that LINQ is essentially declarative programming in a .NET language, and so in many ways encourages developers into a "SQL-like" mindset, even though they are not directly writing SQL. In place of imperative logic and loops, it uses various expressions, operators and declarative logic to build up an "expression tree" describing only what data is required, not the operations to be performed to get it. This expression tree is then parsed by the language compiler, and the result, when used against a relational database, is a SQL string that, while perhaps not always perfect, is often correctly parameterized and certainly no less "optimal" than what is achieved when a developer applies blunt, imperative logic to the SQL language. From a developer standpoint, it is a mistake to consider LINQ simply as a substitute means of querying SQL Server. The strength of LINQ is that that can be used to access any data source, for which a LINQ provider exists. Microsoft supplies built-in providers to access not just SQL Server, but also XML documents, .NET objects, ADO.NET datasets, and Entity Framework elements. LINQ-to-Objects is particularly interesting in that it allows a declarative means to access and manipulate arrays, collections and so on. Furthermore, as Michael Sorens points out in his excellent article on LINQ, there a whole host of third-party LINQ providers, that offers a simple way to get at data in Excel, Google, Flickr and much more, without having to learn a new interface or language. Of course, the need to be generic enough to deal with a range of data sources, from something as mundane as a text file to as esoteric as a relational database, means that LINQ is a compromise and so has inherent limitations. However, it is a powerful and beautifully compact language and one that, at least in its "query syntax" guise, is accessible to developers and DBAs alike. Perhaps there is still hope that LINQ can fulfill Phil Factor's lobster-induced fantasy of a language that will allow us to "treat all data objects, whether Word files, Excel files, XML, relational databases, text files, HTML files, registry files, LDAPs, Outlook and so on, in the same logical way, as linked databases, and extract the metadata, create the entities and relationships in the same way, and use the same SQL syntax to interrogate, create, read, write and update them." Cheers, Tony.

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  • Don't Miss At Devoxx!!!

    - by Yolande Poirier
    Come by IoT Hack Fest which starts with the session: kickstart your Raspberry Pi and/or Leap Motion project, part II on Tuesday from 9:30am to 12:00pm to learn how to start a project with the Raspberry Pi and Leap Motion. In the afternoon, you can still join a project and create your own project with the help of experts on Raspberry Pi, Leap Motion and other boards.  At the Oracle booth, Java experts will be available  to answer your  questions and demo the new features of the Java Platform, including Java Embedded, JavaFX, Java SE and Java EE. This year, the chess game that was first demoed at JavaOne keynotes last September will be showcased at Devoxx.  Duke is coming to Devoxx this year. You can get your picture taken with Duke on Tuesday, Wednesday and Thursday (Nov. 12-14) from 12:00 to 18:00 Beer bash will be Tuesday from 17:30-19:30 and Wednesday/Thursday from 18:00 to 20:00 at the booth. Oracle is raffling off five Raspberry Pi's and a number of books every day. Make sure to stop by and get your badge scanned to enter the raffle. Raffles are Tuesday at 19:15 and Wednesday/Thursday at 19:45 at the Oracle booth.  The main conference sessions from Oracle Java experts are:  Wednesday 13 November Beyond Beauty: JavaFX, Parallax, Touch, Raspberry Pi, Gyroscopes, and Much More Angela Caicedo, Senior Member, Technical Staff, Oracle Room 7, 12:00–13:00 Lambda: A Peek Under the Hood, Brian Goetz, Software Architect, Oracle Room 8, 12:00–13:00 In Full Flow: Java 8 Lambdas in the Stream, Paul Sandoz, Software Developer, Oracle Room 8, 14:00–15:00 The Modular Java Platform and Project Jigsaw, Mark Reinhold, Chief Architect, Java Platform Group, Oracle, Room 8, 15:10–16:10 The Curious Case of JavaScript on the JVM, Attila Szegedi, Principal Member, Technical Staff, Oracle, Room 5, 16:40–17:40 Is It a Car? Is It a Computer? No, It’s a Raspberry Pi JavaFX Informatics System. Simon Ritter, Principal Technology Evangelist, Oracle Room 7, 16:40–17:40 Thursday 14 November Java EE 7: What’s New in the Java EE Platform Linda DeMichiel, Consulting Member, Technical Staff, Oracle, Room 8, 10:50–11:50 Java Microbenchmark Harness: The Lesser of the Two Evils, Aleksey Shipilev, Principal Member, Technical Staff, Oracle. Room 6, 14:00–15:00 Practical Restful Persistence, Shaun Smith, Senior Principal Product Manager, Oracle Room 8, 17:50–18:50 Friday 15 November Avatar.js, Server-Side JavaScript on the Java Platform, Jean-Francois Denise, Software Developer, Oracle Room 8, 11:50–12:50

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  • Java Spotlight Episode 56: Stephan Jenssen, Java Champion, on Devoxx and Parleys

    - by Roger Brinkley
    Tweet Interview with Stephan Janssen, Java Champion, on Devoxx and Parleys Joining us this week on the Java All Star Developer Panel are Dalibor Topic, Java Free and Open Source Software Ambassador and Alexis Moussine-Pouchkine, Java EE Developer Advocate. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link: Java Spotlight Podcast in iTunes. Show Notes News Devoxx Live Recording of the Java Spotlight Podcast. Come be part of the live recording. November 18, 10:45am in BOF 1 room next to the info desk Wanted: Java Code Brainteasers Adopt a JSR Flash to Focus on PC Browsing and Mobile Apps; Adobe to More Aggressively Contribute to HTML5 First binary snapshots of Project Lambda are available JSF 2.2 recent progress - Early Draft Latest OEPE (11.1.1.8) - Eclipse 3.7.1-based  Events Nov 14-18 Devoxx, Antwerp Nov 15-17, DOAG, Nuremberg, Germany Nov 22-25, OTN Developer Days in the Nordics Nov 22-23, Goto Conference, Prague Dec 6-8, Java One Brazil, Sao Paulo Feature interview Stephan Janssen is a serial entrepreneur that has founded several successful organizations such as the Belgian Java User Group (BeJUG) in 1996, JCS Int. in 1998, JavaPolis in 2002 and now Parleys.com in 2006. He has been using Java since its early releases in 1995 with experience of developing and implementing real world Java solutions in the finance and manufacturing industries. Today Stephan is the CTO of the Java Competence Center at RealDolmen. He was selected by BEA Systems as the first European (independent) BEA Technical Director. He has also been recognized by the Server Side as one of the 54 Who is Who in Enterprise Java 2004. Sun has recognized in 2005 his efforts for the Java Community and has engaged him in the Java Champion project. He has spoken at numerous Java and JUG conferences around the world. Mail Bag What's Cool Increased interest in Mobile and Embedded topics, on the heels of the JavaOne announcements. Speaking engagements, etc PodFodder: John Duimovich on IBM & OpenJDK at JavaOne 2011 Oracle Releases Oracle Solaris 11, the First Cloud OS Show Transcripts Transcript for this show is available here when available.

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  • Devoxx!!

    - by Yolande
    0 0 1 350 2000 Oracle Corporation 16 4 2346 14.0 Normal 0 false false false EN-US JA X-NONE /* 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-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;}  Announcing Devoxx London! Taking place on  March 26th and 27th, 2013 right before Devoxx  France on March 28th and 29th, this will be the first  edition of Devoxx UK!. The call for papers begins  on December 1st for Devoxx in London and Paris.  Speakers will be able to present at the two  conferences in the same week. Oracle committed  to fully sponsor the three Devoxx conferences in  2013 with a platinum sponsorship. Over 5,000 developers are expected to attend those conferences. Five dancing NAO robots welcomed attendees at the keynote. Stephan Janssen offers the JUGs to replicate Devoxx4kids workshops using his content and web infrastructure.  He recommended organizing kid events because “the workshops were really fun and such rewarding experience.” Stephan also announced the redesign of Parleys with Html 5 and GlassFish. Friendlier to speakers, they will be able to post their slides online before their talks and then sync the talk's sound track with the slides. Nandini Ramani, VP of product development explained in her keynote address the growing role of Java from enterprise application development to cloud computing to embedded machine-to-machines systems. “Java continues to drive the applications and devices that enrich our interactivity with the world around us” she said. The Java platform has expanded its reach with the OS X and Linux ARM support on Java SE and with two new releases, Java SE embedded and Java embedded Suite 7.0 middleware platform.  Coming up next year is JDK 8, which will include Project Lambda, Project Nashorn and more. As part of that release, JavaFX will offer 3D and third-party component integration. At Devoxx, the slick and interactive schedules were designed with JavaFX. The earliest version of the Java EE 7 SDK is available for download and has WebSocket support, improved JSON support and more.  Stephen Chin arrived on stage with his bike, ending his European NightHacking tour. Check the hacking sessions online here

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  • TechCast Live: "Java and Oracle, One Year Later" Replay Now Available

    - by Justin Kestelyn
    Earlier this week I had the opportunity to chat with Ajay Patel, Oracle's VP leading the Java Evangelist team, about "the state of the union" wrt Oracle and Java. Take a look: And here are some choice quotes, some paraphrased, as helpfully transcribed by Java evangelist Terrence Barr: "One key thing we have learned ... Java is not just a platform, it is also an ecosystem, and you can't have an ecosystem without a community." "The objectives, strategically [for Java at Oracle] have been pretty clear: How do we drive adoption, how do we build a larger, stronger developer community, how do we really make the platform much more competitive." "It's about transparency, involvement. IBM, RedHat, Apple have all agreed to working with us to make OpenJDK the best platform for open source development ... it is a sign that the community has been waiting to move the Java platform forward." "It's not just about Oracle anymore, it's about Java, the technology, the community, the developer base, and how we work with them to move the innovation forward." "Java is strategic to Oracle, and the community is strategic for Java to be successful ... it is critical to our business." On JavaFX 2.0: "... is coming to beta soon, with a release planned in second half [of 2011] ... will give you a new, high-performance graphics engine, the new API for JavaFX ... you will see a very strong, relevant platform for levering rich media platforms." On the JDK and SE: "... aggressively moving forward, JDK 7 is now code complete ... looking good for getting JDK 7 out by summer as we promised. Started work on JDK 8, Jigsaw and Lambda are moving along nicely, on track for JDK 8 release next year ... good progress." On Java EE and Glassfish: "... Very excited to have Glassfish 3.1 released, with clustering and management capabilities ... working with the JCP to shortly submit a number of JSRs for Java EE 7 ... You'll see Java EE 7 becoming the platform for cloud-based development." "You will see Oracle continue to step up to this role of Java steward, making sure that the language, the technology, the platform ... is competitive, relevant, and widely adopted." Making progress!

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  • Some More New ADF Features in JDeveloper 11.1.2

    - by Steven Davelaar
    The official list of new features in JDeveloper 11.1.2 is documented here. While playing with JDeveloper 11.1.2 and scanning the web user interface developer's guide for 11.1.2, I noticed some additional new features in ADF Faces, small but might come in handy:  You can use the af:formatString and af:formatNamed constructs in EL expressions to use substituation variables. For example: <af:outputText value="#{af:formatString('The current user is: {0}',someBean.currentUser)}"/> See section 3.5.2 in web user interface guide for more info. A new ADF Faces Client Behavior tag: af:checkUncommittedDataBehavior. See section 20.3 in web user interface guide for more info. For this tag to work, you also need to set the  uncommittedDataWarning  property on the af:document tag. And this property has quite some issues as you can read here. I did a quick test, the alert is shown for a button that is on the same page, however, if you have a menu in a shell page with dynamic regions, then clicking on another menu item does not raise the alert if you have pending changes in the currently displayed region. For now, the JHeadstart implementation of pending changes still seems the best choice (will blog about that soon). New properties on the af:document tag: smallIconSource creates a so-called favicon that is displayed in front of the URL in the browser address bar. The largeIconSource property specifies the icon used by a mobile device when bookmarking the page to the home page. See section 9.2.5 in web user interface guide for more info. Also notice the failedConnectionText property which I didn't know but was already available in JDeveloper 11.1.1.4. The af:showDetail tag has a new property handleDisclosure which you can set to client for faster rendering. In JDeveloper 11.1.1.x, an expression like #{bindings.JobId.inputValue} would return the internal list index number when JobId was a list binding. To get the actual JobId attribute value, you needed to use #{bindings.JobId.attributeValue}. In JDeveloper 11.1.2 this is no longer needed, the #{bindings.JobId.inputValue} expression will return the attribute value corresponding with the selected index in the choice list. Did you discover other "hidden" new features? Please add them as comment to this blog post so everybody can benefit. 

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  • Is There a Real Advantage to Generic Repository?

    - by Sam
    Was reading through some articles on the advantages of creating Generic Repositories for a new app (example). The idea seems nice because it lets me use the same repository to do several things for several different entity types at once: IRepository repo = new EfRepository(); // Would normally pass through IOC into constructor var c1 = new Country() { Name = "United States", CountryCode = "US" }; var c2 = new Country() { Name = "Canada", CountryCode = "CA" }; var c3 = new Country() { Name = "Mexico", CountryCode = "MX" }; var p1 = new Province() { Country = c1, Name = "Alabama", Abbreviation = "AL" }; var p2 = new Province() { Country = c1, Name = "Alaska", Abbreviation = "AK" }; var p3 = new Province() { Country = c2, Name = "Alberta", Abbreviation = "AB" }; repo.Add<Country>(c1); repo.Add<Country>(c2); repo.Add<Country>(c3); repo.Add<Province>(p1); repo.Add<Province>(p2); repo.Add<Province>(p3); repo.Save(); However, the rest of the implementation of the Repository has a heavy reliance on Linq: IQueryable<T> Query(); IList<T> Find(Expression<Func<T,bool>> predicate); T Get(Expression<Func<T,bool>> predicate); T First(Expression<Func<T,bool>> predicate); //... and so on This repository pattern worked fantastic for Entity Framework, and pretty much offered a 1 to 1 mapping of the methods available on DbContext/DbSet. But given the slow uptake of Linq on other data access technologies outside of Entity Framework, what advantage does this provide over working directly with the DbContext? I attempted to write a PetaPoco version of the Repository, but PetaPoco doesn't support Linq Expressions, which makes creating a generic IRepository interface pretty much useless unless you only use it for the basic GetAll, GetById, Add, Update, Delete, and Save methods and utilize it as a base class. Then you have to create specific repositories with specialized methods to handle all the "where" clauses that I could previously pass in as a predicate. Is the Generic Repository pattern useful for anything outside of Entity Framework? If not, why would someone use it at all instead of working directly with Entity Framework? Edit: Original link doesn't reflect the pattern I was using in my sample code. Here is an (updated link).

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  • Is MongoDB a good choice or not for my application?

    - by shubham
    I have a Reporting application which stores the reports in xml format as recieved from source (XML schema is not defined, it can be any format) and those reports contain some keys and values. Like jobid, setid be keys for 1 type of report and userid, groupId for another type of report etc. The type of keys that can be referred from the document is determined by the namespaces used in the xml doc. These keys are stored on the basis of namespace used in the xml document. For e.g. If a tag in xml fragment uses namespace= "myspace1", then I have keys A and B for myspace1 stored in another table. It will fetch those keys from that table for this namespace, look for their values in xml doc and store it in another table along with the pointer to this xml document (Id of a record storing complete xml document in a cell). Use cases: When the user comes and queries for that key and value, I return the document or a set of documents that are having those key/value pairs. When the user comes and queries for a certain key and provide a name for xslt (pre stored), I fetch the set of documents fulfilling that criteria and convert that xml to html with the specified xslt. When the user comes and asks for a particular fragment of a doc then it can fetch a subset from a particular document also. When the user comes and queries for top x values of a certain key, I return the set of documents that are having top 10 values of that key. I am using DB2 database for its support of xml along with relational capabilities. That makes easier for me to run xpath expressions and fetch values of keys and also aggregate a set of documents fullfilling a criteria, all on the database side. Problems: DB2 stores XML doc of upto 2GB in size. Retrieval is very slow. If some thing involves many documents, then it takes significant time for things to show up in browser, and the user has to wait. Can MongoDb help in this case, as it is document oriented? can I do xml related xpath queries and document transformations on db side? Or is it ok to use both in such a case?

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  • Workflow 4.5 is Awesome, cant wait for 5.0!

    - by JoshReuben
    About 2 years ago I wrote a blog post describing what I would like to see in Workflow vnext: http://geekswithblogs.net/JoshReuben/archive/2010/08/25/workflow-4.0---not-there-yet.aspx At the time WF 4.0 was a little rough around the edges – the State Machine was on codeplex and people were simulating state machines with Flowcharts. Last year I built a near- realtime machine management system using WF 4.0.1 – its managing the internal operations of this device: http://landanano.com/products/commercial   Well WF 4.5 has come a long way – many of my gripes have been addressed: C# expressions - no more VB 'AndAlso' clauses state machine awesomeness - can query current state many designer improvements - Document Outline is so much more succinct than Designer! Separate WCF Service Contract interfaces and ability to generate activities from contract operations ability to rehydrate to updated flow definitions via DynamicUpdateMap and WorkflowIdentity you can read about the new features here: http://msdn.microsoft.com/en-us/library/hh305677(VS.110).aspx   2013 could be the year of Workflow evangelism for .NET, as it comes together as the DSL language. Eg on Azure it could be used to graphically orchestrate between WebRoles, WorkerRoles and AppFabric Queues and the ServiceBus – that would be grand.   Here’s a list of things I’d like to see in Workflow 5.0: Stronger Parallelism support for true multithreaded workflows . A Workflow executes on a single thread – wouldn’t it be great if we had the ability to model TPL DataFlow? Parallel is not really parallel, just allows AsyncCodeActivity.     support for recursion an ExpressionTree activity with an editor design surface a math activity pack return of application level protocol (3.51 WF services) – automatically expose a state machine as a WCF service with bookmark Receive activities generated from OperationContract automatically placed in state transition triggers. A new HTML5 ActivityDesigner control – support with different CSS3  skinnable hooks,  remote connectivity (had to roll my own) A data flow view – crucial to understanding the big picture Ability to refactor a Sequence to custom activity in a separate .xaml file – like Expression Blend does for UserControl state machine global error handling - if all states goto an error state, you quickly get visual spagetti. Now you could nest a state machine, but what if you want an application level protocol whereby each state exposes certain WCF ops. DSL RAD editing - Make the Document Outline into a DSL editor for adding activities  – For WF to really succeed as a higher level of abstraction, It needs to be more productive than raw coding - drag & drop on the designer is currently too slow compared to just typing code. Extensible Wizard API - for pluggable WF editor experience other execution models beyond Sequence, Flowchart & StateMachine: SSIS, Behavior Trees,  Wolfram Model tool – surprise us! improvements to Designer debugging API - SourceLocation is tied to XAML file line number and char position, and ModelService access seems convoluted - why not leverage WPF LogicalTreeHelper / VisualTreeHelper ? Workflow Team , keep on rocking!

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  • What Precalculus knowledge is required before learning Discrete Math Computer Science topics?

    - by Ein Doofus
    Below I've listed the chapters from a Precalculus book as well as the author recommended Computer Science chapters from a Discrete Mathematics book. Although these chapters are from two specific books on these subjects I believe the topics are generally the same between any Precalc or Discrete Math book. What Precalculus topics should one know before starting these Discrete Math Computer Science topics?: Discrete Mathematics CS Chapters 1.1 Propositional Logic 1.2 Propositional Equivalences 1.3 Predicates and Quantifiers 1.4 Nested Quantifiers 1.5 Rules of Inference 1.6 Introduction to Proofs 1.7 Proof Methods and Strategy 2.1 Sets 2.2 Set Operations 2.3 Functions 2.4 Sequences and Summations 3.1 Algorithms 3.2 The Growths of Functions 3.3 Complexity of Algorithms 3.4 The Integers and Division 3.5 Primes and Greatest Common Divisors 3.6 Integers and Algorithms 3.8 Matrices 4.1 Mathematical Induction 4.2 Strong Induction and Well-Ordering 4.3 Recursive Definitions and Structural Induction 4.4 Recursive Algorithms 4.5 Program Correctness 5.1 The Basics of Counting 5.2 The Pigeonhole Principle 5.3 Permutations and Combinations 5.6 Generating Permutations and Combinations 6.1 An Introduction to Discrete Probability 6.4 Expected Value and Variance 7.1 Recurrence Relations 7.3 Divide-and-Conquer Algorithms and Recurrence Relations 7.5 Inclusion-Exclusion 8.1 Relations and Their Properties 8.2 n-ary Relations and Their Applications 8.3 Representing Relations 8.5 Equivalence Relations 9.1 Graphs and Graph Models 9.2 Graph Terminology and Special Types of Graphs 9.3 Representing Graphs and Graph Isomorphism 9.4 Connectivity 9.5 Euler and Hamilton Ptahs 10.1 Introduction to Trees 10.2 Application of Trees 10.3 Tree Traversal 11.1 Boolean Functions 11.2 Representing Boolean Functions 11.3 Logic Gates 11.4 Minimization of Circuits 12.1 Language and Grammars 12.2 Finite-State Machines with Output 12.3 Finite-State Machines with No Output 12.4 Language Recognition 12.5 Turing Machines Precalculus Chapters R.1 The Real-Number System R.2 Integer Exponents, Scientific Notation, and Order of Operations R.3 Addition, Subtraction, and Multiplication of Polynomials R.4 Factoring R.5 Rational Expressions R.6 Radical Notation and Rational Exponents R.7 The Basics of Equation Solving 1.1 Functions, Graphs, Graphers 1.2 Linear Functions, Slope, and Applications 1.3 Modeling: Data Analysis, Curve Fitting, and Linear Regression 1.4 More on Functions 1.5 Symmetry and Transformations 1.6 Variation and Applications 1.7 Distance, Midpoints, and Circles 2.1 Zeros of Linear Functions and Models 2.2 The Complex Numbers 2.3 Zeros of Quadratic Functions and Models 2.4 Analyzing Graphs of Quadratic Functions 2.5 Modeling: Data Analysis, Curve Fitting, and Quadratic Regression 2.6 Zeros and More Equation Solving 2.7 Solving Inequalities 3.1 Polynomial Functions and Modeling 3.2 Polynomial Division; The Remainder and Factor Theorems 3.3 Theorems about Zeros of Polynomial Functions 3.4 Rational Functions 3.5 Polynomial and Rational Inequalities 4.1 Composite and Inverse Functions 4.2 Exponential Functions and Graphs 4.3 Logarithmic Functions and Graphs 4.4 Properties of Logarithmic Functions 4.5 Solving Exponential and Logarithmic Equations 4.6 Applications and Models: Growth and Decay 5.1 Systems of Equations in Two Variables 5.2 System of Equations in Three Variables 5.3 Matrices and Systems of Equations 5.4 Matrix Operations 5.5 Inverses of Matrices 5.6 System of Inequalities and Linear Programming 5.7 Partial Fractions 6.1 The Parabola 6.2 The Circle and Ellipse 6.3 The Hyperbola 6.4 Nonlinear Systems of Equations

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  • Is 2 lines of push/pop code for each pre-draw-state too many?

    - by Griffin
    I'm trying to simplify vector graphics management in XNA; currently by incorporating state preservation. 2X lines of push/pop code for X states feels like too many, and it just feels wrong to have 2 lines of code that look identical except for one being push() and the other being pop(). The goal is to eradicate this repetitiveness,and I hoped to do so by creating an interface in which a client can give class/struct refs in which he wants restored after the rendering calls. Also note that many beginner-programmers will be using this, so forcing lambda expressions or other advanced C# features to be used in client code is not a good idea. I attempted to accomplish my goal by using Daniel Earwicker's Ptr class: public class Ptr<T> { Func<T> getter; Action<T> setter; public Ptr(Func<T> g, Action<T> s) { getter = g; setter = s; } public T Deref { get { return getter(); } set { setter(value); } } } an extension method: //doesn't work for structs since this is just syntatic sugar public static Ptr<T> GetPtr <T> (this T obj) { return new Ptr<T>( ()=> obj, v=> obj=v ); } and a Push Function: //returns a Pop Action for later calling public static Action Push <T> (ref T structure) where T: struct { T pushedValue = structure; //copies the struct data Ptr<T> p = structure.GetPtr(); return new Action( ()=> {p.Deref = pushedValue;} ); } However this doesn't work as stated in the code. How might I accomplish my goal? Example of code to be refactored: protected override void RenderLocally (GraphicsDevice device) { if (!(bool)isCompiled) {Compile();} //TODO: make sure state settings don't implicitly delete any buffers/resources RasterizerState oldRasterState = device.RasterizerState; DepthFormat oldFormat = device.PresentationParameters.DepthStencilFormat; DepthStencilState oldBufferState = device.DepthStencilState; { //Rendering code } device.RasterizerState = oldRasterState; device.DepthStencilState = oldBufferState; device.PresentationParameters.DepthStencilFormat = oldFormat; }

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  • Why would I learn C++11, having known C and C++?

    - by Shahbaz
    I am a programmer in C and C++, although I don't stick to either language and write a mixture of the two. Sometimes having code in classes, possibly with operator overloading, or templates and the oh so great STL is obviously a better way. Sometimes use of a simple C function pointer is much much more readable and clear. So I find beauty and practicality in both languages. I don't want to get into the discussion of "If you mix them and compile with a C++ compiler, it's not a mix anymore, it's all C++" I think we all understand what I mean by mixing them. Also, I don't want to talk about C vs C++, this question is all about C++11. C++11 introduces what I think are significant changes to how C++ works, but it has introduced many special cases that change how different features behave in different circumstances, placing restrictions on multiple inheritance, adding lambda functions, etc. I know that at some point in the future, when you say C++ everyone would assume C++11. Much like when you say C nowadays, you most probably mean C99. That makes me consider learning C++11. After all, if I want to continue writing code in C++, I may at some point need to start using those features simply because my colleagues have. Take C for example. After so many years, there are still many people learning and writing code in C. Why? Because the language is good. What good means is that, it follows many of the rules to create a good programming language. So besides being powerful (which easy or hard, almost all programming languages are), C is regular and has few exceptions, if any. C++11 however, I don't think so. I'm not sure that the changes introduced in C++11 are making the language better. So the question is: Why would I learn C++11? Update: My original question in short was: "I like C++, but the new C++11 doesn't look good because of this and this and this. However, deep down something tells me I need to learn it. So, I asked this question here so that someone would help convince me to learn it." However, the zealous people here can't tolerate pointing out a flaw in their language and were not at all constructive in this manner. After the moderator edited the question, it became more like a "So, how about this new C++11?" which was not at all my question. Therefore, in a day or too I am going to delete this question if no one comes up with an actual convincing argument. P.S. If you are interested in knowing what flaws I was talking about, you can edit my question and see the previous edits.

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  • Software engineering project idea feedback [on hold]

    - by Chris Sewell
    I'm a third year student currently undergoing my project/dissertation section of my degree. I have drafted a proposal for my final year project and would appreciate any feedback. The feedback can be anything constructive either specific to this proposal, the area that I will be working and researching in or my ideas. I will accept all input. Aims My aim is to attempt a proof of concept and prototype a runtime-as-a-service (RaaS). This cloud based runtime will allow clients to dynamically offload tasks or create cloud applications. Currently software-as-a-service (SaaS) cloud applications are purpose built and have a predefined scope in which they can assist or serve the client; this scope cannot be changed without physical alteration to the client and server software. With RaaS the client potentially could define any task it wanted at any time depending on its environment variables, the client and server would then communicate parameters and returns for that task. For the client to utilize a RaaS it must be able to conceive and then define a task using an appropriate XML vocabulary. As the scope of the cloud solution is defined by the client at its runtime, the cloud solution only has to exist for as long as the client requires it to as opposed to a client using a dedicated service. Deliverables The crux of the project will require an XML vocabulary in which the client and server will communicate. I’ll prototype the server application that will dynamically create and manage cloud solutions. The solution will be coded using an interpreted language, such as python or javascript, which can evaluate expressions in runtime or a language that can dynamically compile such as C# or Java. As a further proof of concept I will also produce a mock client that offloads tasks to the server. The report will attempt to explain the different flavours of cloud computing solutions including infrastructure-as-a-service (IaaS), platform-as-a-service (PaaS) and SaaS including real world examples and where the use of a RaaS could have improved the overall example solution. Disclaimer: I'm not requesting stakeholders in my project nor am I delegating work. Any materials other than feedback, advice or directions will not be utilized.

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