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• Clean up after Visual Studio

  - by psheriff

  As programmer’s we know that if we create a temporary file during the running of our application we need to make sure it is removed when the application or process is complete. We do this, but why can’t Microsoft do it? Visual Studio leaves tons of temporary files all over your hard drive. This is why, over time, your computer loses hard disk space. This blog post will show you some of the most common places where these files are left and which ones you can safely delete..NET Left OversVisual Studio is a great development environment for creating applications quickly. However, it will leave a lot of miscellaneous files all over your hard drive. There are a few locations on your hard drive that you should be checking to see if there are left-over folders or files that you can delete. I have attempted to gather as much data as I can about the various versions of .NET and operating systems. Of course, your mileage may vary on the folders and files I list here. In fact, this problem is so prevalent that PDSA has created a Computer Cleaner specifically for the Visual Studio developer.  Instructions for downloading our PDSA Developer Utilities (of which Computer Cleaner is one) are at the end of this blog entry.Each version of Visual Studio will create “temporary” files in different folders. The problem is that the files created are not always “temporary”. Most of the time these files do not get cleaned up like they should. Let’s look at some of the folders that you should periodically review and delete files within these folders.Temporary ASP.NET FilesAs you create and run ASP.NET applications from Visual Studio temporary files are placed into the <sysdrive>:\Windows\Microsoft.NET\Framework[64]\<vernum>\Temporary ASP.NET Files folder. The folders and files under this folder can be removed with no harm to your development computer. Do not remove the "Temporary ASP.NET Files" folder itself, just the folders underneath this folder. If you use IIS for ASP.NET development, you may need to run the iisreset.exe utility from the command prompt prior to deleting any files/folder under this folder. IIS will sometimes keep files in use in this folder and iisreset will release the locks so the files/folders can be deleted.Website CacheThis folder is similar to the ASP.NET Temporary Files folder in that it contains files from ASP.NET applications run from Visual Studio. This folder is located in each users local settings folder. The location will be a little different on each operating system. For example on Windows Vista/Windows 7, the folder is located at <sysdrive>:\Users\<UserName>\AppData\Local\Microsoft\WebsiteCache. If you are running Windows XP this folder is located at <sysdrive>:\ Documents and Settings\<UserName>\Local Settings\Application Data\Microsoft\WebsiteCache. Check these locations periodically and delete all files and folders under this directory.Visual Studio BackupThis backup folder is used by Visual Studio to store temporary files while you develop in Visual Studio. This folder never gets cleaned out, so you should periodically delete all files and folders under this directory. On Windows XP, this folder is located at <sysdrive>:\Documents and Settings\<UserName>\My Documents\Visual Studio 200[5|8]\Backup Files. On Windows Vista/Windows 7 this folder is located at <sysdrive>:\Users\<UserName>\Documents\Visual Studio 200[5|8]\.Assembly CacheNo, this is not the global assembly cache (GAC). It appears that this cache is only created when doing WPF or Silverlight development with Visual Studio 2008 or Visual Studio 2010. This folder is located in <sysdrive>:\ Users\<UserName>\AppData\Local\assembly\dl3 on Windows Vista/Windows 7. On Windows XP this folder is located at <sysdrive>:\ Documents and Settings\<UserName>\Local Settings\Application Data\assembly. If you have not done any WPF or Silverlight development, you may not find this particular folder on your machine.Project AssembliesThis is yet another folder where Visual Studio stores temporary files. You will find a folder for each project you have opened and worked on. This folder is located at <sysdrive>:\Documents and Settings\<UserName>Local Settings\Application Data\Microsoft\Visual Studio\[8|9].0\ProjectAssemblies on Windows XP. On Microsoft Vista/Windows 7 you will find this folder at <sysdrive>:\Users\<UserName>\AppData\Local\Microsoft\Visual Studio\[8|9].0\ProjectAssemblies.Remember not all of these folders will appear on your particular machine. Which ones do show up will depend on what version of Visual Studio you are using, whether or not you are doing desktop or web development, and the operating system you are using.SummaryTaking the time to periodically clean up after Visual Studio will aid in keeping your computer running quickly and increase the space on your hard drive. Another place to make sure you are cleaning up is your TEMP folder. Check your OS settings for the location of your particular TEMP folder and be sure to delete any files in here that are not in use. I routinely clean up the files and folders described in this blog post and I find that I actually eliminate errors in Visual Studio and I increase my hard disk space.NEW! PDSA has just published a “pre-release” of our PDSA Developer Utilities at http://www.pdsa.com/DeveloperUtilities that contains a Computer Cleaner utility which will clean up the above-mentioned folders, as well as a lot of other miscellaneous folders that get Visual Studio build-up. You can download a free trial at http://www.pdsa.com/DeveloperUtilities. If you wish to purchase our utilities through the month of November, 2011 you can use the RSVP code: DUNOV11 to get them for only $39. This is $40 off the regular price.NOTE: You can download this article and many samples like the one shown in this blog entry at my website. http://www.pdsa.com/downloads. Select “Tips and Tricks”, then “Developer Machine Clean Up” from the drop down list.Good Luck with your Coding,Paul Sheriff** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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• NoSQL Memcached API for MySQL: Latest Updates

  - by Mat Keep

  With data volumes exploding, it is vital to be able to ingest and query data at high speed. For this reason, MySQL has implemented NoSQL interfaces directly to the InnoDB and MySQL Cluster (NDB) storage engines, which bypass the SQL layer completely. Without SQL parsing and optimization, Key-Value data can be written directly to MySQL tables up to 9x faster, while maintaining ACID guarantees. In addition, users can continue to run complex queries with SQL across the same data set, providing real-time analytics to the business or anonymizing sensitive data before loading to big data platforms such as Hadoop, while still maintaining all of the advantages of their existing relational database infrastructure. This and more is discussed in the latest Guide to MySQL and NoSQL where you can learn more about using the APIs to scale new generations of web, cloud, mobile and social applications on the world's most widely deployed open source database The native Memcached API is part of the MySQL 5.6 Release Candidate, and is already available in the GA release of MySQL Cluster. By using the ubiquitous Memcached API for writing and reading data, developers can preserve their investments in Memcached infrastructure by re-using existing Memcached clients, while also eliminating the need for application changes. Speed, when combined with flexibility, is essential in the world of growing data volumes and variability. Complementing NoSQL access, support for on-line DDL (Data Definition Language) operations in MySQL 5.6 and MySQL Cluster enables DevOps teams to dynamically update their database schema to accommodate rapidly changing requirements, such as the need to capture additional data generated by their applications. These changes can be made without database downtime. Using the Memcached interface, developers do not need to define a schema at all when using MySQL Cluster. Lets look a little more closely at the Memcached implementations for both InnoDB and MySQL Cluster. Memcached Implementation for InnoDB The Memcached API for InnoDB is previewed as part of the MySQL 5.6 Release Candidate. As illustrated in the following figure, Memcached for InnoDB is implemented via a Memcached daemon plug-in to the mysqld process, with the Memcached protocol mapped to the native InnoDB API. Figure 1: Memcached API Implementation for InnoDB With the Memcached daemon running in the same process space, users get very low latency access to their data while also leveraging the scalability enhancements delivered with InnoDB and a simple deployment and management model. Multiple web / application servers can remotely access the Memcached / InnoDB server to get direct access to a shared data set. With simultaneous SQL access, users can maintain all the advanced functionality offered by InnoDB including support for Foreign Keys, XA transactions and complex JOIN operations. Benchmarks demonstrate that the NoSQL Memcached API for InnoDB delivers up to 9x higher performance than the SQL interface when inserting new key/value pairs, with a single low-end commodity server supporting nearly 70,000 Transactions per Second. Figure 2: Over 9x Faster INSERT Operations The delivered performance demonstrates MySQL with the native Memcached NoSQL interface is well suited for high-speed inserts with the added assurance of transactional guarantees. You can check out the latest Memcached / InnoDB developments and benchmarks here You can learn how to configure the Memcached API for InnoDB here Memcached Implementation for MySQL Cluster Memcached API support for MySQL Cluster was introduced with General Availability (GA) of the 7.2 release, and joins an extensive range of NoSQL interfaces that are already available for MySQL Cluster Like Memcached, MySQL Cluster provides a distributed hash table with in-memory performance. MySQL Cluster extends Memcached functionality by adding support for write-intensive workloads, a full relational model with ACID compliance (including persistence), rich query support, auto-sharding and 99.999% availability, with extensive management and monitoring capabilities. All writes are committed directly to MySQL Cluster, eliminating cache invalidation and the overhead of data consistency checking to ensure complete synchronization between the database and cache. Figure 3: Memcached API Implementation with MySQL Cluster Implementation is simple: 1. The application sends reads and writes to the Memcached process (using the standard Memcached API). 2. This invokes the Memcached Driver for NDB (which is part of the same process) 3. The NDB API is called, providing for very quick access to the data held in MySQL Cluster’s data nodes. The solution has been designed to be very flexible, allowing the application architect to find a configuration that best fits their needs. It is possible to co-locate the Memcached API in either the data nodes or application nodes, or alternatively within a dedicated Memcached layer. The benefit of this flexible approach to deployment is that users can configure behavior on a per-key-prefix basis (through tables in MySQL Cluster) and the application doesn’t have to care – it just uses the Memcached API and relies on the software to store data in the right place(s) and to keep everything synchronized. Using Memcached for Schema-less Data By default, every Key / Value is written to the same table with each Key / Value pair stored in a single row – thus allowing schema-less data storage. Alternatively, the developer can define a key-prefix so that each value is linked to a pre-defined column in a specific table. Of course if the application needs to access the same data through SQL then developers can map key prefixes to existing table columns, enabling Memcached access to schema-structured data already stored in MySQL Cluster. Conclusion Download the Guide to MySQL and NoSQL to learn more about NoSQL APIs and how you can use them to scale new generations of web, cloud, mobile and social applications on the world's most widely deployed open source database See how to build a social app with MySQL Cluster and the Memcached API from our on-demand webinar or take a look at the docs Don't hesitate to use the comments section below for any questions you may have 

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• $.fadeTo/fadeOut() operations on Table Rows in IE fail

  - by Rick Strahl

  Here’s a a small problem that one of customers ran into a few days ago: He was playing around with some of the sample code I’ve put out for one of my simple jQuery demos which deals with providing a simple pulse behavior plug-in: $.fn.pulse = function(time) { if (!time) time = 2000; // *** this == jQuery object that contains selections $(this).fadeTo(time, 0.20, function() { $(this).fadeTo(time, 1); }); return this; } it’s a very simplistic plug-in and it works fine for simple pulse animations. However he ran into a problem where it didn’t work when working with tables – specifically pulsing a table row in Internet Explorer. Works fine in FireFox and Chrome, but IE not so much. It also works just fine in IE as long as you don’t try it on tables or table rows specifically. Applying against something like this (an ASP.NET GridView): var sel = $("#gdEntries>tbody>tr") .not(":first-child") // no header .not(":last-child") // no footer .filter(":even") .addClass("gridalternate"); // *** Demonstrate simple plugin sel.pulse(2000); fails in IE. No pulsing happens in any version of IE. After some additional experimentation with single rows and various ways of selecting each and still failing, I’ve come to the conclusion that the various fade operations in jQuery simply won’t work correctly in IE (any version). So even something as ‘elemental’ as this: var el = $("#gdEntries>tbody>tr").get(0);$(el).fadeOut(2000); is not working correctly. The item will stick around for 2 seconds and then magically disappear. Likewise: sel.hide().fadeIn(5000); also doesn’t fade in although the items become immediately visible in IE. Go figure that behavior out. Thanks to a tweet from red_square and a link he provided here is a grid that explains what works and doesn’t in IE (and most last gen browsers) regarding opacity: http://www.quirksmode.org/js/opacity.html It appears from this link that table and row elements can’t be made opaque, but td elements can. This means for the row selections I can force each of the td elements to be selected and then pulse all of those. Once you have the rows it’s easy to explicitly select all the columns in those rows with .find(“td”). Aha the following actually works: var sel = $("#gdEntries>tbody>tr") .not(":first-child") // no header .not(":last-child") // no footer .filter(":even") .addClass("gridalternate"); // *** Demonstrate simple plugin sel.find("td").pulse(2000); A little unintuitive that, but it works. Stay away from <table> and <tr> Fades The moral of the story is – stay away from TR, TH and TABLE fades and opacity. If you have to do it on tables use the columns instead and if necessary use .find(“td”) on your row(s) selector to grab all the columns. I’ve been surprised by this uhm relevation, since I use fadeOut in almost every one of my applications for deletion of items and row deletions from grids are not uncommon especially in older apps. But it turns out that fadeOut actually works in terms of behavior: It removes the item when the timeout’s done and because the fade is relatively short lived and I don’t extensively test IE code any more I just never noticed that the fade wasn’t happening. Note – this behavior or rather lack thereof appears to be specific to table table,tr,th elements. I see no problems with other elements like <div> and <li> items. Chalk this one up to another of IE’s shortcomings. Incidentally I’m not the only one who has failed to address this in my simplistic plug-in: The jquery-ui pulsate effect also fails on the table rows in the same way. sel.effect("pulsate", { times: 3 }, 2000); and it also works with the same workaround. If you’re already using jquery-ui definitely use this version of the plugin which provides a few more options… Bottom line: be careful with table based fade operations and remember that if you do need to fade – fade on columns.© Rick Strahl, West Wind Technologies, 2005-2010Posted in jQuery  

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• What is the most efficient way to convert to binary and back in C#?

  - by Saad Imran.

  I'm trying to write a general purpose socket server for a game I'm working on. I know I could very well use already built servers like SmartFox and Photon, but I wan't to go through the pain of creating one myself for learning purposes. I've come up with a BSON inspired protocol to convert the the basic data types, their arrays, and a special GSObject to binary and arrange them in a way so that it can be put back together into object form on the client end. At the core, the conversion methods utilize the .Net BitConverter class to convert the basic data types to binary. Anyways, the problem is performance, if I loop 50,000 times and convert my GSObject to binary each time it takes about 5500ms (the resulting byte[] is just 192 bytes per conversion). I think think this would be way too slow for an MMO that sends 5-10 position updates per second with a 1000 concurrent users. Yes, I know it's unlikely that a game will have a 1000 users on at the same time, but like I said earlier this is supposed to be a learning process for me, I want to go out of my way and build something that scales well and can handle at least a few thousand users. So yea, if anyone's aware of other conversion techniques or sees where I'm loosing performance I would appreciate the help. GSBitConverter.cs This is the main conversion class, it adds extension methods to main datatypes to convert to the binary format. It uses the BitConverter class to convert the base types. I've shown only the code to convert integer and integer arrays, but the rest of the method are pretty much replicas of those two, they just overload the type. public static class GSBitConverter { public static byte[] ToGSBinary(this short value) { return BitConverter.GetBytes(value); } public static byte[] ToGSBinary(this IEnumerable<short> value) { List<byte> bytes = new List<byte>(); short length = (short)value.Count(); bytes.AddRange(length.ToGSBinary()); for (int i = 0; i < length; i++) bytes.AddRange(value.ElementAt(i).ToGSBinary()); return bytes.ToArray(); } public static byte[] ToGSBinary(this bool value); public static byte[] ToGSBinary(this IEnumerable<bool> value); public static byte[] ToGSBinary(this IEnumerable<byte> value); public static byte[] ToGSBinary(this int value); public static byte[] ToGSBinary(this IEnumerable<int> value); public static byte[] ToGSBinary(this long value); public static byte[] ToGSBinary(this IEnumerable<long> value); public static byte[] ToGSBinary(this float value); public static byte[] ToGSBinary(this IEnumerable<float> value); public static byte[] ToGSBinary(this double value); public static byte[] ToGSBinary(this IEnumerable<double> value); public static byte[] ToGSBinary(this string value); public static byte[] ToGSBinary(this IEnumerable<string> value); public static string GetHexDump(this IEnumerable<byte> value); } Program.cs Here's the the object that I'm converting to binary in a loop. class Program { static void Main(string[] args) { GSObject obj = new GSObject(); obj.AttachShort("smallInt", 15); obj.AttachInt("medInt", 120700); obj.AttachLong("bigInt", 10900800700); obj.AttachDouble("doubleVal", Math.PI); obj.AttachStringArray("muppetNames", new string[] { "Kermit", "Fozzy", "Piggy", "Animal", "Gonzo" }); GSObject apple = new GSObject(); apple.AttachString("name", "Apple"); apple.AttachString("color", "red"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.5); GSObject lemon = new GSObject(); apple.AttachString("name", "Lemon"); apple.AttachString("color", "yellow"); apple.AttachBool("inStock", false); apple.AttachFloat("price", (float)0.8); GSObject apricoat = new GSObject(); apple.AttachString("name", "Apricoat"); apple.AttachString("color", "orange"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.9); GSObject kiwi = new GSObject(); apple.AttachString("name", "Kiwi"); apple.AttachString("color", "green"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)2.3); GSArray fruits = new GSArray(); fruits.AddGSObject(apple); fruits.AddGSObject(lemon); fruits.AddGSObject(apricoat); fruits.AddGSObject(kiwi); obj.AttachGSArray("fruits", fruits); Stopwatch w1 = Stopwatch.StartNew(); for (int i = 0; i < 50000; i++) { byte[] b = obj.ToGSBinary(); } w1.Stop(); Console.WriteLine(BitConverter.IsLittleEndian ? "Little Endian" : "Big Endian"); Console.WriteLine(w1.ElapsedMilliseconds + "ms"); } Here's the code for some of my other classes that are used in the code above. Most of it is repetitive. GSObject GSArray GSWrappedObject

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• Partition Wise Joins

  - by jean-pierre.dijcks

  Some say they are the holy grail of parallel computing and PWJ is the basis for a shared nothing system and the only join method that is available on a shared nothing system (yes this is oversimplified!). The magic in Oracle is of course that is one of many ways to join data. And yes, this is the old flexibility vs. simplicity discussion all over, so I won't go there... the point is that what you must do in a shared nothing system, you can do in Oracle with the same speed and methods. The Theory A partition wise join is a join between (for simplicity) two tables that are partitioned on the same column with the same partitioning scheme. In shared nothing this is effectively hard partitioning locating data on a specific node / storage combo. In Oracle is is logical partitioning. If you now join the two tables on that partitioned column you can break up the join in smaller joins exactly along the partitions in the data. Since they are partitioned (grouped) into the same buckets, all values required to do the join live in the equivalent bucket on either sides. No need to talk to anyone else, no need to redistribute data to anyone else... in short, the optimal join method for parallel processing of two large data sets. PWJ's in Oracle Since we do not hard partition the data across nodes in Oracle we use the Partitioning option to the database to create the buckets, then set the Degree of Parallelism (or run Auto DOP - see here) and get our PWJs. The main questions always asked are: How many partitions should I create? What should my DOP be? In a shared nothing system the answer is of course, as many partitions as there are nodes which will be your DOP. In Oracle we do want you to look at the workload and concurrency, and once you know that to understand the following rules of thumb. Within Oracle we have more ways of joining of data, so it is important to understand some of the PWJ ideas and what it means if you have an uneven distribution across processes. Assume we have a simple scenario where we partition the data on a hash key resulting in 4 hash partitions (H1 -H4). We have 2 parallel processes that have been tasked with reading these partitions (P1 - P2). The work is evenly divided assuming the partitions are the same size and we can scan this in time t1 as shown below. Now assume that we have changed the system and have a 5th partition but still have our 2 workers P1 and P2. The time it takes is actually 50% more assuming the 5th partition has the same size as the original H1 - H4 partitions. In other words to scan these 5 partitions, the time t2 it takes is not 1/5th more expensive, it is a lot more expensive and some other join plans may now start to look exciting to the optimizer. Just to post the disclaimer, it is not as simple as I state it here, but you get the idea on how much more expensive this plan may now look... Based on this little example there are a few rules of thumb to follow to get the partition wise joins. First, choose a DOP that is a factor of two (2). So always choose something like 2, 4, 8, 16, 32 and so on... Second, choose a number of partitions that is larger or equal to 2* DOP. Third, make sure the number of partitions is divisible through 2 without orphans. This is also known as an even number... Fourth, choose a stable partition count strategy, which is typically hash, which can be a sub partitioning strategy rather than the main strategy (range - hash is a popular one). Fifth, make sure you do this on the join key between the two large tables you want to join (and this should be the obvious one...). Translating this into an example: DOP = 8 (determined based on concurrency or by using Auto DOP with a cap due to concurrency) says that the number of partitions >= 16. Number of hash (sub) partitions = 32, which gives each process four partitions to work on. This number is somewhat arbitrary and depends on your data and system. In this case my main reasoning is that if you get more room on the box you can easily move the DOP for the query to 16 without repartitioning... and of course it makes for no leftovers on the table... And yes, we recommend up-to-date statistics. And before you start complaining, do read this post on a cool way to do stats in 11.

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• Simple Excel Export with EPPlus

  - by Jesse Taber

  Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/10/30/simple-excel-export-with-epplus.aspxAnyone I’ve ever met who works with an application that sits in front of a lot of data loves it when they can get that data exported to an Excel file for them to mess around with offline. As both developer and end user of a little website project that I’ve been working on, I found myself wanting to be able to get a bunch of the data that the application was collecting into an Excel file. The great thing about being both an end user and a developer on a project is that you can build the features that you really want! While putting this feature together I came across the fantastic EPPlus library. This library is certainly very well known and popular, but I was so impressed with it that I thought it was worth a quick blog post. This library is extremely powerful; it lets you create and manipulate Excel 2007/2010 spreadsheets in .NET code with a high degree of flexibility. My only gripe with the project is that they are not touting how insanely easy it is to build a basic Excel workbook from a simple data source. If I were running this project the approach I’m about to demonstrate in this post would be front and center on the landing page for the project because it shows how easy it really is to get started and serves as a good way to ease yourself in to some of the more advanced features. The website in question uses RavenDB, which means that we’re dealing with POCOs to model the data throughout all layers of the application. I love working like this so when it came time to figure out how to export some of this data to an Excel spreadsheet I wanted to find a way to take an IEnumerable<T> and just have it dumped to Excel with each item in the collection being modeled as a single row in the Excel worksheet. Consider the following class: public class Employee { public int Id { get; set; } public string Name { get; set; } public decimal HourlyRate { get; set; } public DateTime HireDate { get; set; } } Now let’s say we have a collection of these represented as an IEnumerable<Employee> and we want to be able to output it to an Excel file for offline querying/manipulation. As it turns out, this is dead simple to do with EPPlus. Have a look: public void ExportToExcel(IEnumerable<Employee> employees, FileInfo targetFile) { using (var excelFile = new ExcelPackage(targetFile)) { var worksheet = excelFile.Workbook.Worksheets.Add("Sheet1"); worksheet.Cells["A1"].LoadFromCollection(Collection: employees, PrintHeaders: true); excelFile.Save(); } } That’s it. Let’s break down what’s going on here: Create a ExcelPackage to model the workbook (Excel file). Note that the ‘targetFile’ value here is a FileInfo object representing the location on disk where I want the file to be saved. Create a worksheet within the workbook. Get a reference to the top-leftmost cell (addressed as A1) and invoke the ‘LoadFromCollection’ method, passing it our collection of Employee objects. Behind the scenes this is reflecting over the properties of the type provided and pulling out any public members to become columns in the resulting Excel output. The ‘PrintHeaders’ parameter tells EPPlus to grab the name of the property and put it in the first row. Save the Excel file All of the heavy lifting here is being done by the ‘LoadFromCollection’ method, and that’s a good thing. Now, this was really easy to do, but it has some limitations. Using this approach you get a very plain, un-styled Excel worksheet. The column widths are all set to the default. The number format for all cells is ‘General’ (which proves particularly interesting if you have a DateTime property in your data source). I’m a “no frills” guy, so I wasn’t bothered at all by trading off simplicity for style and formatting. That said, EPPlus has tons of samples that you can download that illustrate how to apply styles and formatting to cells and a ton of other advanced features that are way beyond the scope of this post.

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• SQL Developer Data Modeler v3.3 Early Adopter: Collaborative Design via Excel?

  - by thatjeffsmith

  As you may have heard last week, we have a new version of Oracle SQL Developer Data Modeler now available as an Early Adopter release. Version 3.3 has quite a few new features and I’ll be previewing them here. Today’s topic is our new Excel integration. It builds off of last week’s lesson: Search, so you may want to go read that first. They say it takes a village to raise a child. I say it takes a team to build a data model. You have your techie folks, your business folks, your in-betweeners, and your database geeks. Who gets to define how customers are represented and stored in your database? That data lives forever, so you better get it right from the beginning, or you’ll be living in a hacker’s paradise for years to come. Lots of good rantings, ravings, and advice on this topic in general on Karen Lopez’s (@datachick) blog. But let’s say you are the primary modeler on a project. You dutifully interview the business folks for their requirements. You sit down and start to model and think you’re pretty close. Now you need someone to confirm your assumptions and provide some feedback. Do you send your model over? Take a screenshot and blow it up on a whiteboard? Export to HTML and let them take a magic marker to their monitors? Or maybe you bite the bullet and install your modeling software on their desktops and take the hours or days required to train them up on how to use the the tool. Wouldn’t it be nice if they could just mark up their corrections in Excel and let you suck the updates back in? This is what we have started to build in Oracle SQL Developer Data Modeler. Let’s say you have a new table called ‘UT_STARTUPS.’ It looks a little something like this: A table in Oracle SQL Developer Data Modeler What I would like to do is have my team or co-worker review how I have defined those columns. Perhaps TIMESTAMP is overkill or maybe the column names themselves aren’t up to snuff. What I am going to do is now search for all the columns in my table, then export that to Excel. So do a search for UT_STARTUPS. Search, filter, then Report With the filter set to ‘Columns,’ if I do a report I’ll be only getting the columns that are resolving to my search term. So as long as my table name is unique in the model, I should get what I’m looking for. Here’s what I see when I click on the Report button: XLS or XLSX, either format is just fine I want to decide how the Column data is exported to Excel though, so I’m going to create a report template that I can use going forward. So click the ‘Manage’ button and setup a new template. I’m going to call mine ‘CollaborativeDevelopment.’ The templates allow me to define what properties are included in the reports. Once this is set, I’ll have the XLS file generated, and get to work Now let the Excel junkies do their stuff Note that not ALL of the report properties are update-able (yes, I made up a new word there) via Excel. We’ll have the full list of properties documented going forward, but in my Excel sheet, note that I can’t change the table name or the data types for the columns. I’m going to update some column names and supply ‘nice’ comments so the database users know what’s what. Here’s my input for the designer/architect/database dude: Be kind, please rew…use comments. Save the file, email it back to your modeler. Update the model from Excel That’s right, it’s a right mouse click from your model in the tree If everything goes right, you’ll see a nice confirmation message: It’s alive! Another to-do item on tap – making this dialog more informative. We’ll be showing exactly what in your model was updated from Excel. Let’s take another look at the model now Voila! Why are we doing this again? The goal is to reduce the number of round-trips from the modeler and the business process owner. One is used to working with Excel – why not allow them to mark up their changes in the tool they already know? This is an early adopter release and I anticipate this feature getting a good bit of tuning up before we release. Why don’t you download 3.3, give it a whirl, and let us know what you think?

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• Creating Visual Studio projects that only contain static files

  - by Eilon

  Have you ever wanted to create a Visual Studio project that only contained static files and didn’t contain any code? While working on ASP.NET MVC we had a need for exactly this type of project. Most of the projects in the ASP.NET MVC solution contain code, such as managed code (C#), unit test libraries (C#), and Script# code for generating our JavaScript code. However, one of the projects, MvcFuturesFiles, contains no code at all. It only contains static files that get copied to the build output folder: As you may well know, adding static files to an existing Visual Studio project is easy. Just add the file to the project and in the property grid set its Build Action to “Content” and the Copy to Output Directory to “Copy if newer.” This works great if you have just a few static files that go along with other code that gets compiled into an executable (EXE, DLL, etc.). But this solution does not work well if the projects only contains static files and has no compiled code. If you create a new project in Visual Studio and add static files to it you’ll still get an EXE or DLL copied to the output folder, despite not having any actual code. We wanted to avoid having a teeny little DLL generated in the output folder. In ASP.NET MVC 2 we came up with a simple solution to this problem. We started out with a regular C# Class Library project but then edited the project file to alter how it gets built. The critical part to get this to work is to define the MSBuild targets for Build, Clean, and Rebuild to perform custom tasks instead of running the compiler. The Build, Clean, and Rebuild targets are the three main targets that Visual Studio requires in every project so that the normal UI functions properly. If they are not defined then running certain commands in Visual Studio’s Build menu will cause errors. Once you create the class library projects there are a few easy steps to change it into a static file project: The first step in editing the csproj file is to remove the reference to the Microsoft.CSharp.targets file because the project doesn’t contain any C# code: <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The second step is to define the new Build, Clean, and Rebuild targets to delete and then copy the content files: <Target Name="Build"> <Copy SourceFiles="@(Content)" DestinationFiles="@(Content->'$(OutputPath)%(RelativeDir)%(Filename)%(Extension)')" /> </Target> <Target Name="Clean"> <Exec Command="rd /s /q $(OutputPath)" Condition="Exists($(OutputPath))" /> </Target> <Target Name="Rebuild" DependsOnTargets="Clean;Build"> </Target> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The third and last step is to add all the files to the project as normal Content files (as you would do in any project type). To see how we did this in the ASP.NET MVC 2 project you can download the source code and inspect the MvcFutureFules.csproj project file. If you’re working on a project that contains many static files I hope this solution helps you out!

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• Anti-Forgery Request in ASP.NET MVC and AJAX

  - by Dixin

  Background To secure websites from cross-site request forgery (CSRF, or XSRF) attack, ASP.NET MVC provides an excellent mechanism: The server prints tokens to cookie and inside the form; When the form is submitted to server, token in cookie and token inside the form are sent by the HTTP request; Server validates the tokens. To print tokens to browser, just invoke HtmlHelper.AntiForgeryToken():<% using (Html.BeginForm()) { %> <%: this.Html.AntiForgeryToken(Constants.AntiForgeryTokenSalt)%> <%-- Other fields. --%> <input type="submit" value="Submit" /> <% } %> which writes to token to the form:<form action="..." method="post"> <input name="__RequestVerificationToken" type="hidden" value="J56khgCvbE3bVcsCSZkNVuH9Cclm9SSIT/ywruFsXEgmV8CL2eW5C/gGsQUf/YuP" /> <!-- Other fields. --> <input type="submit" value="Submit" /> </form> and the cookie: __RequestVerificationToken_Lw__=J56khgCvbE3bVcsCSZkNVuH9Cclm9SSIT/ywruFsXEgmV8CL2eW5C/gGsQUf/YuP When the above form is submitted, they are both sent to server. [ValidateAntiForgeryToken] attribute is used to specify the controllers or actions to validate them:[HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult Action(/* ... */) { // ... } This is very productive for form scenarios. But recently, when resolving security vulnerabilities for Web products, I encountered 2 problems: It is expected to add [ValidateAntiForgeryToken] to each controller, but actually I have to add it for each POST actions, which is a little crazy; After anti-forgery validation is turned on for server side, AJAX POST requests will consistently fail. Specify validation on controller (not on each action) Problem For the first problem, usually a controller contains actions for both HTTP GET and HTTP POST requests, and usually validations are expected for HTTP POST requests. So, if the [ValidateAntiForgeryToken] is declared on the controller, the HTTP GET requests become always invalid:[ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public class SomeController : Controller { [HttpGet] public ActionResult Index() // Index page cannot work at all. { // ... } [HttpPost] public ActionResult PostAction1(/* ... */) { // ... } [HttpPost] public ActionResult PostAction2(/* ... */) { // ... } // ... } If user sends a HTTP GET request from a link: http://Site/Some/Index, validation definitely fails, because no token is provided. So the result is, [ValidateAntiForgeryToken] attribute must be distributed to each HTTP POST action in the application:public class SomeController : Controller { [HttpGet] public ActionResult Index() // Works. { // ... } [HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult PostAction1(/* ... */) { // ... } [HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult PostAction2(/* ... */) { // ... } // ... } Solution To avoid a large number of [ValidateAntiForgeryToken] attributes (one attribute for one HTTP POST action), I created a wrapper class of ValidateAntiForgeryTokenAttribute, where HTTP verbs can be specified:[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)] public class ValidateAntiForgeryTokenWrapperAttribute : FilterAttribute, IAuthorizationFilter { private readonly ValidateAntiForgeryTokenAttribute _validator; private readonly AcceptVerbsAttribute _verbs; public ValidateAntiForgeryTokenWrapperAttribute(HttpVerbs verbs) : this(verbs, null) { } public ValidateAntiForgeryTokenWrapperAttribute(HttpVerbs verbs, string salt) { this._verbs = new AcceptVerbsAttribute(verbs); this._validator = new ValidateAntiForgeryTokenAttribute() { Salt = salt }; } public void OnAuthorization(AuthorizationContext filterContext) { string httpMethodOverride = filterContext.HttpContext.Request.GetHttpMethodOverride(); if (this._verbs.Verbs.Contains(httpMethodOverride, StringComparer.OrdinalIgnoreCase)) { this._validator.OnAuthorization(filterContext); } } } When this attribute is declared on controller, only HTTP requests with the specified verbs are validated:[ValidateAntiForgeryTokenWrapper(HttpVerbs.Post, Constants.AntiForgeryTokenSalt)] public class SomeController : Controller { // Actions for HTTP GET requests are not affected. // Only HTTP POST requests are validated. } Now one single attribute on controller turns on validation for all HTTP POST actions. Submit token via AJAX Problem For AJAX scenarios, when request is sent by JavaScript instead of form:$.post(url, { productName: "Tofu", categoryId: 1 // Token is not posted. }, callback); This kind of AJAX POST requests will always be invalid, because server side code cannot see the token in the posted data. Solution The token must be printed to browser then submitted back to server. So first of all, HtmlHelper.AntiForgeryToken() must be called in the page where the AJAX POST will be sent. Then jQuery must find the printed token in the page, and post it:$.post(url, { productName: "Tofu", categoryId: 1, __RequestVerificationToken: getToken() // Token is posted. }, callback); To be reusable, this can be encapsulated in a tiny jQuery plugin:(function ($) { $.getAntiForgeryToken = function () { // HtmlHelper.AntiForgeryToken() must be invoked to print the token. return $("input[type='hidden'][name='__RequestVerificationToken']").val(); }; var addToken = function (data) { // Converts data if not already a string. if (data && typeof data !== "string") { data = $.param(data); } data = data ? data + "&" : ""; return data + "__RequestVerificationToken=" + encodeURIComponent($.getAntiForgeryToken()); }; $.postAntiForgery = function (url, data, callback, type) { return $.post(url, addToken(data), callback, type); }; $.ajaxAntiForgery = function (settings) { settings.data = addToken(settings.data); return $.ajax(settings); }; })(jQuery); Then in the application just replace $.post() invocation with $.postAntiForgery(), and replace $.ajax() instead of $.ajaxAntiForgery():$.postAntiForgery(url, { productName: "Tofu", categoryId: 1 }, callback); // Token is posted. This solution looks hard coded and stupid. If you have more elegant solution, please do tell me.

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• WebGL First Person Camera - Matrix issues

  - by Ryan Welsh

  I have been trying to make a WebGL FPS camera.I have all the inputs working correctly (I think) but when it comes to applying the position and rotation data to the view matrix I am a little lost. The results can be viewed here http://thistlestaffing.net/masters/camera/index.html and the code here var camera = { yaw: 0.0, pitch: 0.0, moveVelocity: 1.0, position: [0.0, 0.0, -70.0] }; var viewMatrix = mat4.create(); var rotSpeed = 0.1; camera.init = function(canvas){ var ratio = canvas.clientWidth / canvas.clientHeight; var left = -1; var right = 1; var bottom = -1.0; var top = 1.0; var near = 1.0; var far = 1000.0; mat4.frustum(projectionMatrix, left, right, bottom, top, near, far); viewMatrix = mat4.create(); mat4.rotateY(viewMatrix, viewMatrix, camera.yaw); mat4.rotateX(viewMatrix, viewMatrix, camera.pitch); mat4.translate(viewMatrix, viewMatrix, camera.position); } camera.update = function(){ viewMatrix = mat4.create(); mat4.rotateY(viewMatrix, viewMatrix, camera.yaw); mat4.rotateX(viewMatrix, viewMatrix, camera.pitch); mat4.translate(viewMatrix, viewMatrix, camera.position); } //prevent camera pitch from going above 90 and reset yaw when it goes over 360 camera.lockCamera = function(){ if(camera.pitch > 90.0){ camera.pitch = 90; } if(camera.pitch < -90){ camera.pitch = -90; } if(camera.yaw <0.0){ camera.yaw = camera.yaw + 360; } if(camera.yaw >360.0){ camera.yaw = camera.yaw - 0.0; } } camera.translateCamera = function(distance, direction){ //calculate where we are looking at in radians and add the direction we want to go in ie WASD keys var radian = glMatrix.toRadian(camera.yaw + direction); //console.log(camera.position[3], radian, distance, direction); //calc X coord camera.position[0] = camera.position[0] - Math.sin(radian) * distance; //calc Z coord camera.position[2] = camera.position [2] - Math.cos(radian) * distance; console.log(camera.position [2] - (Math.cos(radian) * distance)); } camera.rotateUp = function(distance, direction){ var radian = glMatrix.toRadian(camera.pitch + direction); //calc Y coord camera.position[1] = camera.position[1] + Math.sin(radian) * distance; } camera.moveForward = function(){ if(camera.pitch!=90 && camera.pitch!=-90){ camera.translateCamera(-camera.moveVelocity, 0.0); } camera.rotateUp(camera.moveVelocity, 0.0); } camera.moveBack = function(){ if(camera.pitch!=90 && camera.pitch!=-90){ camera.translateCamera(-camera.moveVelocity, 180.0); } camera.rotateUp(camera.moveVelocity, 180.0); } camera.moveLeft = function(){ camera.translateCamera(-camera.moveVelocity, 270.0); } camera.moveRight = function(){ camera.translateCamera(-camera.moveVelocity, 90.0); } camera.lookUp = function(){ camera.pitch = camera.pitch + rotSpeed; camera.lockCamera(); } camera.lookDown = function(){ camera.pitch = camera.pitch - rotSpeed; camera.lockCamera(); } camera.lookLeft = function(){ camera.yaw= camera.yaw - rotSpeed; camera.lockCamera(); } camera.lookRight = function(){ camera.yaw = camera.yaw + rotSpeed; camera.lockCamera(); } . If there is no problem with my camera then I am doing some matrix calculations within my draw function where a problem might be. //position cube 1 worldMatrix = mat4.create(); mvMatrix = mat4.create(); mat4.translate(worldMatrix, worldMatrix, [-20.0, 0.0, -30.0]); mat4.multiply(mvMatrix, worldMatrix, viewMatrix); setShaderMatrix(); gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer); gl.vertexAttribPointer(shaderProgram.attPosition, 3, gl.FLOAT, false, 8*4,0); gl.vertexAttribPointer(shaderProgram.attTexCoord, 2, gl.FLOAT, false, 8*4, 3*4); gl.vertexAttribPointer(shaderProgram.attNormal, 3, gl.FLOAT, false, 8*4, 5*4); gl.activeTexture(gl.TEXTURE0); gl.bindTexture(gl.TEXTURE_2D, myTexture); gl.uniform1i(shaderProgram.uniSampler, 0); gl.useProgram(shaderProgram); gl.drawArrays(gl.TRIANGLES, 0, vertexBuffer.numItems); //position cube 2 worldMatrix = mat4.create(); mvMatrix = mat4.create(); mat4.multiply(mvMatrix, worldMatrix, viewMatrix); mat4.translate(worldMatrix, worldMatrix, [40.0, 0.0, -30.0]); setShaderMatrix(); gl.drawArrays(gl.TRIANGLES, 0, vertexBuffer.numItems); //position cube 3 worldMatrix = mat4.create(); mvMatrix = mat4.create(); mat4.multiply(mvMatrix, worldMatrix, viewMatrix); mat4.translate(worldMatrix, worldMatrix, [20.0, 0.0, -100.0]); setShaderMatrix(); gl.drawArrays(gl.TRIANGLES, 0, vertexBuffer.numItems); camera.update();

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• can't load big files to server with php [closed]

  - by yozhik

  Hi all! I can't load big files to server. The problem is in that file $_FILES["filename"]["tmp_name"] is empty if file a little more bigger then 2mb. I tried to change variables in php.ini upload_max_filesize = 700M post_max_size = 16M but not working to. Also tried to add this variables to my .httaccess file - but 500 error appears. Error code while uploading=1. UPLOAD_ERR_INI_SIZE Value: 1; The uploaded file exceeds the upload_max_filesize directive in php.ini. Here is my uppload.php page, please anwer what I doing wrong? Thanx! <?php if(strlen($_FILES["filename"]["name"])) { $folder = "uploads/"; echo $folder; $error = ""; if($_FILES["filename"]["size"] > 1024*700*1024) { $error .= "<b><p class=ErrorMessage>?????? ????? ????????? 5Mb</p></b><br>"; header("Location: upload.php?error=".$error, true, 303 ); } if(!file_exists($folder.="hh/")) { if(!mkdir($folder, 0700)) $error .= "<b><p class=ErrorMessage>Folder not created</p></b><br>"; } //echo "<br>".$_FILES["filename"]["tmp_name"]."<br>"; echo $folder.$_FILES["filename"]["name"]."<br>"; echo $_FILES["filename"]["error"]."<br>"; if(move_uploaded_file($_FILES["filename"]["tmp_name"], $folder.$_FILES["filename"]["name"])) { echo("???? ??????? ???????? <br>"); echo("?????????????? ?????: <br>"); echo("??? ?????: "); echo($_FILES["filename"]["name"]); echo("<br>?????? ?????: "); echo($_FILES["filename"]["size"]); echo("<br>??????? ??? ????????: "); echo($folder.=$_FILES["filename"]["name"]); echo("<br>??? ?????: "); echo($_FILES["filename"]["type"]); } else { $error .= "<b><p class=ErrorMessage>?????? ???????? ?????</p></b><br>"; } } ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>???????? ??? ????????</title> </head> <body> <?php if(isset($_REQUEST["error"])) { echo $_REQUEST["error"]; } ?> <h2><p><b> ????? ??? ???????? ?????? </b></p></h2> <form action="upload.php" method="post" enctype="multipart/form-data"> <input type="file" name="filename" READONLY><br> <input name="Upload" type="submit" value="Upload"><br> </form> </body> </html>

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• A Graduate&rsquo;s Journey at Oracle &ndash; Bhaskar Ghosh From Oracle India

  - by david.talamelli

  I am Bhaskar Ghosh, and I work as an Applications Engineer with Oracle. Well, it was three years ago when my journey with one of the largest software companies started. It was a fine day and a decisive moment, when I was placed in Oracle as a campus recruit from College of Engineering Guindy, Anna University, Chennai! I always thought of looking back, the time that helped me learn beyond my boundaries, think broader and ahead, and grow – technically, professionally and personally. Hmmn! Let me recall the eventful moments once again. My first day as an intern at Oracle started in late 2007. I met one of the Oracle Managers at the Oracle Campus in Hyderabad and on the same day I also met another Oracle employee who was to later to become my first manager. I was charged and thrilled with the environment and the wonderful people around me! I was joined by two other interns, who also had a Masters in Computer Applications. We formed a very friendly group with all the interns and the new hires, and shared our excitement and learning. Myself and one of the other Graduates started working on a very interesting project on Semantic technology. We finally had our names added as co-developers for this very project. This phase of five months was the time and we learnt tremendously and worked very hard, partly because we had to travel back and forth to our colleges to submit reports and present for the Masters in Computer Applications final year project reviews. After completing my MCA, I joined as a full-time employee in 2008. During the next year, we worked on interesting and bleeding edge technologies - OWL, RDF, SPARQL, Visualization, J2EE, Social Web features, Semantic Web technologies, Web Services and many more! We developed cool, rich internet and desktop applications. Little did I know at that time, that this learning would help me tremendously for my the next project in Oracle. The following year saw me being assigned a role in a different project that my other team members were working on for the last two years. It took me two months to understand and get into a flow with this new task. I was fortunate that this phase helped me enhance my inter-personal and communication skills, as much as it helped me grow professionally with better ability to tackle multiple priorities and switch between tasks based on the team’s requirements. I was made the POC for all communications with our team and other product teams. I personally feel that this time enhanced me tremendously in technologies like Oracle Forms, J2EE, and Java and Web Services. The last six months, saw myself becoming an Institute of Electrical and Electronics Engineer member, and continuing my higher education International Institute of Information Technology, Hyderabad. Oracle supports its employees becoming members of professional bodies, and higher studies are supported by management, I think it is tremendously helpful in the professional and technical growth of the employees. Last three months, I have been working on great and useful enhancements to our product. Ah beautiful! All these years, there have been other moments and events of fun that are too worth mentioning. Clubs and groups at Oracle such as Employee Club, Oracle Volunteers, Football Club, etc. have always kept on organizing numerous events and competitions, full of fun and entertainment. I really enjoyed participating, even if it was small, in the intra-Oracle football tourney, Oracle Volunteer Days, OraFora, OraOvations, and a few more. Those ‘Seasons of Sharing’, those ‘Blood Donation camps’, those ‘Diwali and Christmas gifts and events’, those ‘fun events at the annual function called OraOvations’, those ‘books and cycle stalls’, and those so many other things… It only fills my mind with pleasure. The last three years have been very eventful:they have been full of learning and growth, and under the very able and encouraging guidance of my manager. I have got the opportunity to know about and/or interact with many wonderful personalities, and learn from them, here at Oracle. The environment, the people, and the fellow developers have been so friendly, and always ever ready to help, when we were in doubt.. I really love the big office space, and the flexible timings, and the caring people around. I look forward to a beautiful, learning and motivating journey with Oracle.

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• CQRS - Benefits

  - by Dylan Smith

  Thanks to all the comments and feedback from the last post I think I have a better understanding now of the benefits of CQRS (separate from the benefits of Event Sourcing). I’m going to try and sum it up here, and point out some areas where I could still use some advice: CQRS Benefits Sounds like the primary benefit of CQRS as an architecture is it allows you to create a simpler domain model by sucking out everything related to queries. I can definitely see the benefit to this, in general the domain logic related to commands is the high-value behavior in the software, but the logic required to service the queries would add a lot of low-value “noise” to the domain model that would dilute the high-value (command) behavior – sorting, paging, filtering, pre-fetch paths, etc. Also the most appropriate domain structure for implementing commands might not be the most optimal for implementing queries. To paraphrase Greg, this usually results in a domain model that is mediocre at both, piss-poor at one, or more likely piss-poor at both commands and queries. Not only will you be able to simplify your domain model by pulling out all the query logic, but at least a handful of commands in most systems will probably be “pass-though” type commands with little to no logic that just generate events. If these can be implemented directly in the command-handler and never touch the domain model, this allows you to slim down the domain model even more. Also, if you were to do event sourcing without CQRS, you no longer have a database containing the current state (only the domain model would) which makes it difficult (or impossible) to support ad-hoc querying and/or reporting that is common in most business software. Of course CQRS provides some great scalability benefits, not only scalability but I have to assume that it provides extremely low latency for most operations, especially if you have an asynchronous event bus. I know Greg says that you get a 3x scaling (Commands, Queries, Client) of your ability to perform parallel development, but IMHO, it seems like it only provides 1.5x scaling since even without CQRS you’re going to have your client loosely coupled to your domain - which is still a great benefit to be able to realize. Questions / Concerns If all the queries against an aggregate get pulled out to the Query layer, what if the only commands for that aggregate can be handled in a “pass-through” manner with the command handler directly generating events. Is it possible to have an aggregate that isn’t modeled in the domain model? Are there any issues or downsides to this? I know in the feedback from my previous posts it was suggested that having one domain model handling both commands and queries requires implementing a lot of traversals between objects that wouldn’t be necessary if it was only servicing commands. My question is, do you include traversals in your domain model based on the needs of the code, or based on the conceptual domain model? If none of my Commands require a Customer.Orders traversal, but the conceptual domain includes the concept of a set of orders belonging to a customer – should I model that in my domain model or not? I like the idea of using the Query side of the architecture as a place to put junior devs where the risk of them screwing something up has minimal impact. But I’m not sold on the idea that you can actually outsource it. Like I said in one of my comments on my previous post, the code to handle a query and generate DTO’s is going to be dead simple, but the code to process events and apply them to the tables on the query side is going to require a significant amount of domain knowledge to know which events to listen for to update each of the de-normalized tables (and what changes need to be made when each event is processed). I don’t know about everybody else, but having Indian/Russian/whatever outsourced developers have to do anything that requires significant domain knowledge has never been successful in my experience. And if you need to spec out for each new query which events to listen to and what to do with each one, well that’s probably going to be just as much work to document as it would be to just implement it. Greg made the point in a comment that doing an aggregate query like “Total Sales By Customer” is going to be inefficient if you use event sourcing but not CQRS. I don’t understand why that would be the case. I imagine in that case you’d simply have a method/property on the Customer object that calculated total sales for that customer by enumerating over the Orders collection. Then the application services layer would generate DTO’s off of the Customers collection that included say the CustomerID, CustomerName, TotalSales, or whatever the case may be. As long as you use a snapshotting implementation, I don’t see why that would be anymore inefficient in a DDD+Event Sourcing implementation than in a typical DDD implementation. Like I mentioned in my last post I still have some questions about query logic that haven’t been answered yet, but before I start asking those I want to make sure I have a strong grasp on what benefits CQRS provides.  My main concern with the query logic was that I know I could just toss it all into the query side, but I was concerned that I would be losing the benefits of using CQRS in the first place if I did that.  I want to elaborate more on this though with some example situations in an upcoming post.

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• SQL SERVER – Powershell – Importing CSV File Into Database – Video

  - by pinaldave

  Laerte Junior is my very dear friend and Powershell Expert. On my request he has agreed to share Powershell knowledge with us. Laerte Junior is a SQL Server MVP and, through his technology blog and simple-talk articles, an active member of the Microsoft community in Brasil. He is a skilled Principal Database Architect, Developer, and Administrator, specializing in SQL Server and Powershell Programming with over 8 years of hands-on experience. He holds a degree in Computer Science, has been awarded a number of certifications (including MCDBA), and is an expert in SQL Server 2000 / SQL Server 2005 / SQL Server 2008 technologies. Let us read the blog post in his own words. I was reading an excellent post from my great friend Pinal about loading data from CSV files, SQL SERVER – Importing CSV File Into Database – SQL in Sixty Seconds #018 – Video,   to SQL Server and was honored to write another guest post on SQL Authority about the magic of the PowerShell. The biggest stuff in TechEd NA this year was PowerShell. Fellows, if you still don’t know about it, it is better to run. Remember that The Core Servers to SQL Server are the future and consequently the Shell. You don’t want to be out of this, right? Let’s see some PowerShell Magic now. To start our tour, first we need to download these two functions from Powershell and SQL Server Master Jedi Chad Miller.Out-DataTable and Write-DataTable. Save it in a module and add it in your profile. In my case, the module is called functions.psm1. To have some data to play, I created 10 csv files with the same content. I just put the SQL Server Errorlog into a csv file and created 10 copies of it. #Just create a CSV with data to Import. Using SQLErrorLog [reflection.assembly]::LoadWithPartialName(“Microsoft.SqlServer.Smo”) $ServerInstance=new-object (“Microsoft.SqlServer.Management.Smo.Server“) $Env:Computername $ServerInstance.ReadErrorLog() | export-csv-path“c:\SQLAuthority\ErrorLog.csv”-NoTypeInformation for($Count=1;$Count-le 10;$count++)  {       Copy-Item“c:\SQLAuthority\Errorlog.csv”“c:\SQLAuthority\ErrorLog$($count).csv” } Now in my path c:\sqlauthority, I have 10 csv files : Now it is time to create a table. In my case, the SQL Server is called R2D2 and the Database is SQLServerRepository and the table is CSV_SQLAuthority. CREATE TABLE [dbo].[CSV_SQLAuthority]( [LogDate] [datetime] NULL, [Processinfo] [varchar](20) NULL, [Text] [varchar](MAX) NULL ) Let’s play a little bit. I want to import synchronously all csv files from the path to the table: #Importing synchronously $DataImport=Import-Csv-Path ( Get-ChildItem“c:\SQLAuthority\*.csv”) $DataTable=Out-DataTable-InputObject$DataImport Write-DataTable-ServerInstanceR2D2-DatabaseSQLServerRepository-TableNameCSV_SQLAuthority-Data$DataTable Very cool, right? Let’s do it asynchronously and in background using PowerShell  Jobs: #If you want to do it to all asynchronously Start-job-Name‘ImportingAsynchronously‘ ` -InitializationScript  {IpmoFunctions-Force-DisableNameChecking} ` -ScriptBlock {    ` $DataImport=Import-Csv-Path ( Get-ChildItem“c:\SQLAuthority\*.csv”) $DataTable=Out-DataTable-InputObject$DataImport Write-DataTable   -ServerInstance“R2D2″`                   -Database“SQLServerRepository“`                   -TableName“CSV_SQLAuthority“`                   -Data$DataTable             } Oh, but if I have csv files that are large in size and I want to import each one asynchronously. In this case, this is what should be done: Get-ChildItem“c:\SQLAuthority\*.csv” | % { Start-job-Name“$($_)” ` -InitializationScript  {IpmoFunctions-Force-DisableNameChecking} ` -ScriptBlock { $DataImport=Import-Csv-Path$args[0]                $DataTable=Out-DataTable-InputObject$DataImport                Write-DataTable-ServerInstance“R2D2″`                               -Database“SQLServerRepository“`                               -TableName“CSV_SQLAuthority“`                               -Data$DataTable             } -ArgumentList$_.fullname } How cool is that? Let’s make the funny stuff now. Let’s schedule it on an SQL Server Agent Job. If you are using SQL Server 2012, you can use the PowerShell Job Step. Otherwise you need to use a CMDexec job step calling PowerShell.exe. We will use the second option. First, create a ps1 file called ImportCSV.ps1 with the script above and save it in a path. In my case, it is in c:\temp\automation. Just add the line at the end: Get-ChildItem“c:\SQLAuthority\*.csv” | % { Start-job-Name“$($_)” ` -InitializationScript  {IpmoFunctions-Force-DisableNameChecking} ` -ScriptBlock { $DataImport=Import-Csv-Path$args[0]                $DataTable=Out-DataTable-InputObject$DataImport                Write-DataTable-ServerInstance“R2D2″`                               -Database“SQLServerRepository“`                               -TableName“CSV_SQLAuthority“`                               -Data$DataTable             } -ArgumentList$_.fullname } Get-Job | Wait-Job | Out-Null Remove-Job -State Completed Why? See my post Dooh PowerShell Trick–Running Scripts That has Posh Jobs on a SQL Agent Job Remember, this trick is for  ALL scripts that will use PowerShell Jobs and any kind of schedule tool (SQL Server agent, Windows Schedule) Create a Job Called ImportCSV and a step called Step_ImportCSV and choose CMDexec. Then you just need to schedule or run it. I did a short video (with matching good background music) and you can see it at: That’s it guys. C’mon, join me in the #PowerShellLifeStyle. You will love it. If you want to check what we can do with PowerShell and SQL Server, don’t miss Laerte Junior LiveMeeting on July 18. You can have more information in : LiveMeeting VC PowerShell PASS–Troubleshooting SQL Server With PowerShell–English Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology, Video Tagged: Powershell

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• Geocaching - World wide treasure hunt

  I'm not quite sure how I came across this topic but actually I find it absolutely interesting, challenging and most of all a great fun for the family and friends. The interesting part is for sure that you can follow other peoples treasures and their preferred locations where a cache might be hidden. Of course, it wont be easy to find a cache after all. Sometimes there are even 'mystery caches' which have either riddles, further instructions or little brain games for you in order to find the actual cache - that's the challenge. And last but not least, those caches are hidden outdoor. A great experience to explore nature either on your own, or your family especially with children, or as a treasure hunting pack with a couple of friends. What is geocaching? It's a high-tech outdoor treasure hunting game that's a great way to explore the world with friends, family or on your own. Participants use GPS-enabled devices to locate hidden containers called geocaches. There are over one million geocaches hidden around the world today, waiting for you to find them. Visit Geocaching.com to search for geocaches near you.(Source: Referral Email of geocaching.com) Checkout the Geocaching 101 for further details and information. They also provide a video channel on YouTube. Which equipment do I need? Any GPS-enabled device is sufficient to go onto the hunt. I'm going to start our geocaching experience equipped with my Samsung Galaxy Tab. Additionally, I installed a geocaching.com client called c:geo that hopefully assists me soon. Combined with a map app like Google Maps and a nice Compass app you should be fully equipped and ready to go. I guess, that even a car navigation system is perfect for that task. Later on, with more experience and demand for technology (or precision) it might be interesting to opt-in for a pure GPS device, like a Garmin or any other brand on the market. {loadposition content_adsense} What is a geocache and what does it contain? In its simplest form, a cache always contains a logbook or logsheet for you to log your find. Larger caches may contain a logbook and any number of items. These items turn the adventure into a true treasure hunt. You never know what the cache owner or visitors to the cache may have left for you to enjoy. Remember, if you take something, leave something of equal or greater value in return. It is recommended that items in a cache be individually packaged in a clear, zipped plastic bag to protect them from the elements. Finding your first geocache Well, first you have to have interest to pick up the challenge. Then you have to check out the Geocache directory on geocaching.com. They have recommendations for beginner's caches but you are free to choose any. Actually, we have a Mystery Cache very close to our base, and I guess that we are going for that one on our first trip. Anyway, there is a very informative guide on the website which should answer all your questions about starting your new outdoor adventure. For sure, it's going to be rewarding. Team up with friends and family Especially as a beginner there might be misunderstandings in handling the GPS coordinates, the compass, or the map, and even finding the container at the documented position isn't easy in the first place. Luckily, there are logbook reports online from other hunters, and most of the time there are even 'spoiler' images available. But also bear in mind, that a geocache might have been removed or is lost due to unconscious people or whatever other reasons. Don't be disappointed in case that you can't find anything... There be nothing anymore. A general recommendation in this case would be to replace the missing container with a new one, and give feedback to the original owner about the state of that particular location. After all, it's about fun and active participation in a world-wide community. Geocaches in Mauritius? Yes, there are currently about 45 geocaches spread all over the island, and even a single in Rodriguez - that's gonna be a tough one. Hopefully, we will get increasing numbers as Geocaching.com allows, no better, even encourages you to hide new containers at your locations of choice. I think this is going to be real fun for us during the upcoming weeks and months. Especially, when we are travelling to other countries and transfer so-called trackable items between geocaches. On my first impression, Geocaching.com seems to be very mature, open and community-oriented. There are literally hundreds of thousands geocache 'hunters' all over the world. And usually finding a container remote from your home is very rewarding. I'll keep you updated in these matters during the next months to come...

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• C# 4.0: Covariance And Contravariance In Generics

  - by Paulo Morgado

  C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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• Spolskism or Twitterism: A Doctor writes...

  - by Phil Factor

  "I never realized I had a problem. I just 'twittered' because it was a social thing to do. All my mates were doing it. It made me feel good to have 'followers'; it bolstered my self-esteem. Of course, you don't think of the long-term effects on your work and on the way you think. There's no denying that it impairs your judgment…" Yes, this story is typical. Hundreds of people are waking up to the long term effects of twittering, and seeking help. Dave, who wishes to remain anonymous, told our reporter… "I started using Twitter at work. Just a few minutes now and then, throughout the day. A lot of my colleagues were doing it and I thought 'Well, that's cool; it must be part of what I should be doing at work'. Soon, I was avidly reading every twitter that came my way, and counting the minutes between my own twitters. I tried to kid myself that it was all about professional development and getting other people to help you with work-related problems, but in truth I had become addicted to the buzz of the social network. The worse thing was that it made me seem busy even when I was really just frittering my time away. Inevitably, I started to get behind with my real work." Experts have identified the syndrome and given it a name: 'Twitterism', sometimes referred to as 'Spolskism', after the person who first drew attention to the pernicious damage to well-being that the practice caused, and who had the courage to take the pledge of rejecting it. According to one expert… "The occasional Twitter does little harm to the participant, and can be an adaptive way of dealing with stress. Unfortunately, it rarely stops there. The addictive qualities of the practice have put a strain on the caring professions who are faced with a flood of people making that first bold step to seeking help". Dave is one of those now seeking help for his addiction… "I had lost touch with reality. Even though I twittered my work colleagues constantly, I found I actually spoke to them less and less. Even when out socializing, I would frequently disengage from the conversation, in order to twitter. I stopped blogging. I stopped responding to emails; the only way to reach me was through the world of Twitter. Unfortunately, my denial about the harm that twittering was doing to me, my friends, and my work-colleagues was so strong that I truly couldn't see that I had a problem." Like other addictions, the help and support of others who are 'taking the cure' is important. There is a common bond between those who have 'been through hell and back' and are once more able to experience the joys of actually conversing and socializing, rather than the false comfort of solitary 'twittering'. Complete abstinence is essential to the cure. Most of those who risk even an occasional twitter face a headlong slide back into 'binge' twittering. Tom, another twitterer who has managed to kick the habit explains… "My twittering addiction now seems more like a bad dream. You get to work, and switch on the PC. You say to yourself, just open up the browser, just for a minute, just to see what people are saying on Twitter. The next thing you know, half the day has gone by. The worst thing is that when you're addicted, you get good at covering up the habit; I spent so much time looking at the screen and typing on the keyboard, people just assumed I was working hard.I know that I must never forget what it was like then, and what it's like now that I've kicked the habit. I now have more time for productive work and a real social life." Like many addictions, Spolskism has its most detrimental effects on family, friends and workmates, rather than the addict. So often nowadays, we hear the sad stories of Twitter-Widows; tales of long lonely evenings spent whilst their partners are engrossed in their twittering into their 'mobiles' or indulging in their solitary spolskistic habits in privacy, under cover of 'having to do work at home'. Workmates suffer too, when the addicts even take their laptops or mobiles into meetings in order to 'twitter' with their fellow obsessives, even stooping to complain to their followers how boring the meeting is. No; The best advice is to leave twittering to the birds. You know it makes sense.

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• Code Metrics: Number of IL Instructions

  - by DigiMortal

  In my previous posting about code metrics I introduced how to measure LoC (Lines of Code) in .NET applications. Now let’s take a step further and let’s take a look how to measure compiled code. This way we can somehow have a picture about what compiler produces. In this posting I will introduce you code metric called number of IL instructions. NB! Number of IL instructions is not something you can use to measure productivity of your team. If you want to get better idea about the context of this metric and LoC then please read my first posting about LoC. What are IL instructions? When code written in some .NET Framework language is compiled then compiler produces assemblies that contain byte code. These assemblies are executed later by Common Language Runtime (CLR) that is code execution engine of .NET Framework. The byte code is called Intermediate Language (IL) – this is more common language than C# and VB.NET by example. You can use ILDasm tool to convert assemblies to IL assembler so you can read them. As IL instructions are building blocks of all .NET Framework binary code these instructions are smaller and highly general – we don’t want very rich low level language because it executes slower than more general language. For every method or property call in some .NET Framework language corresponds set of IL instructions. There is no 1:1 relationship between line in high level language and line in IL assembler. There are more IL instructions than lines in C# code by example. How much instructions there are? I have no common answer because it really depends on your code. Here you can see some metrics from my current community project that is developed on SharePoint Server 2007. As average I have about 7 IL instructions per line of code. This is not metric you should use, it is just illustrative example so you can see the differences between numbers of lines and IL instructions. Why should I measure the number of IL instructions? Just take a look at chart above. Compiler does something that you cannot see – it compiles your code to IL. This is not intuitive process because you usually cannot say what is exactly the end result. You know it at greater plain but you don’t know it exactly. Therefore we can expect some surprises and that’s why we should measure the number of IL instructions. By example, you may find better solution for some method in your source code. It looks nice, it works nice and everything seems to be okay. But on server under load your fix may be way slower than previous code. Although you minimized the number of lines of code it ended up with increasing the number of IL instructions. How to measure the number of IL instructions? My choice is NDepend because Visual Studio is not able to measure this metric. Steps to make are easy. Open your NDepend project or create new and add all your application assemblies to project (you can also add Visual Studio solution to project). Run project analysis and wait until it is done. You can see over-all stats form global summary window. This is the same window I used to read the LoC and the number of IL instructions metrics for my chart. Meanwhile I made some changes to my code (enabled advanced caching for events and event registrations module) and then I ran code analysis again to get results for this section of this posting. NDepend is also able to tell you exactly what parts of code have problematically much IL instructions. The code quality section of CQL Query Explorer shows you how much problems there are with members in analyzed code. If you click on the line Methods too big (NbILInstructions) you can see all the problematic members of classes in CQL Explorer shown in image on right. In my case if have 10 methods that are too big and two of them have horrible number of IL instructions – just take a look at first two methods in this TOP10. Also note the query box. NDepend has easy and SQL-like query language to query code analysis results. You can modify these queries if you like and also you can define your own ones if default set is not enough for you. What is good result? As you can see from query window then the number of IL instructions per member should have maximally 200 IL instructions. Of course, like always, the less instructions you have, the better performing code you have. I don’t mean here little differences but big ones. By example, take a look at my first method in warnings list. The number of IL instructions it has is huge. And believe me – this method looks awful. Conclusion The number of IL instructions is useful metric when optimizing your code. For analyzing code at general level to find out too long methods you can use the number of LoC metric because it is more intuitive for you and you can therefore handle the situation more easily. Also you can use NDepend as code metrics tool because it has a lot of metrics to offer.

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• Find only physical network adapters with WMI Win32_NetworkAdapter class

  - by Mladen Prajdic

  WMI is Windows Management Instrumentation infrastructure for managing data and machines. We can access it by using WQL (WMI querying language or SQL for WMI). One thing to remember from the WQL link is that it doesn't support ORDER BY. This means that when you do SELECT * FROM wmiObject, the returned order of the objects is not guaranteed. It can return adapters in different order based on logged-in user, permissions of that user, etc… This is not documented anywhere that I've looked and is derived just from my observations. To get network adapters we have to query the Win32_NetworkAdapter class. This returns us all network adapters that windows detect, real and virtual ones, however it only supplies IPv4 data. I've tried various methods of combining properties that are common on all systems since Windows XP. The first thing to do to remove all virtual adapters (like tunneling, WAN miniports, etc…) created by Microsoft. We do this by adding WHERE Manufacturer!='Microsoft' to our WMI query. This greatly narrows the number of adapters we have to work with. Just on my machine it went from 20 adapters to 5. What was left were one real physical Realtek LAN adapter, 2 virtual adapters installed by VMware and 2 virtual adapters installed by VirtualBox. If you read the Win32_NetworkAdapter help page you'd notice that there's an AdapterType that enumerates various adapter types like LAN or Wireless and AdapterTypeID that gives you the same information as AdapterType only in integer form. The dirty little secret is that these 2 properties don't work. They are both hardcoded, AdapterTypeID to "0" and AdapterType to "Ethernet 802.3". The only exceptions I've seen so far are adapters that have no values at all for the two properties, "RAS Async Adapter" that has values of AdapterType = "Wide Area Network" and AdapterTypeID = "3" and various tunneling adapters that have values of AdapterType = "Tunnel" and AdapterTypeID = "15". In the help docs there isn't even a value for 15. So this property was of no help. Next property to give hope is NetConnectionId. This is the name of the network connection as it appears in the Control Panel -> Network Connections. Problem is this value is also localized into various languages and can have different names for different connection. So both of these properties don't help and we haven't even started talking about eliminating virtual adapters. Same as the previous one this property was also of no help. Next two properties I checked were ConfigManagerErrorCode and NetConnectionStatus in hopes of finding disabled and disconnected adapters. If an adapter is enabled but disconnected the ConfigManagerErrorCode = 0 with different NetConnectionStatus. If the adapter is disabled it reports ConfigManagerErrorCode = 22. This looked like a win by using (ConfigManagerErrorCode=0 or ConfigManagerErrorCode=22) in our condition. This way we get enabled (connected and disconnected adapters). Problem with all of the above properties is that none of them filter out the virtual adapters installed by virtualization software like VMware and VirtualBox. The last property to give hope is PNPDeviceID. There's an interesting observation about physical and virtual adapters with this property. Every virtual adapter PNPDeviceID starts with "ROOT\". Even VMware and VirtualBox ones. There were some really, really old physical adapters that had PNPDeviceID starting with "ROOT\" but those were in pre win XP era AFAIK. Since my minimum system to check was Windows XP SP2 I didn't have to worry about those. The only virtual adapter I've seen to not have PNPDeviceID start with "ROOT\" is the RAS Async Adapter for Wide Area Network. But because it is made by Microsoft we've eliminated it with the first condition for the manufacturer. Using the PNPDeviceID has so far proven to be really effective and I've tested it on over 20 different computers of various configurations from Windows XP laptops with wireless and bluetooth cards to virtualized Windows 2008 R2 servers. So far it always worked as expected. I will appreciate you letting me know if you find a configuration where it doesn't work. Let's see some C# code how to do this: ManagementObjectSearcher mos = null;// WHERE Manufacturer!='Microsoft' removes all of the // Microsoft provided virtual adapters like tunneling, miniports, and Wide Area Network adapters.mos = new ManagementObjectSearcher(@"SELECT * FROM Win32_NetworkAdapter WHERE Manufacturer != 'Microsoft'");// Trying the ConfigManagerErrorCode and NetConnectionStatus variations // proved to still not be enough and it returns adapters installed by // the virtualization software like VMWare and VirtualBox// ConfigManagerErrorCode = 0 -> Device is working properly. This covers enabled and/or disconnected devices// ConfigManagerErrorCode = 22 AND NetConnectionStatus = 0 -> Device is disabled and Disconnected. // Some virtual devices report ConfigManagerErrorCode = 22 (disabled) and some other NetConnectionStatus than 0mos = new ManagementObjectSearcher(@"SELECT * FROM Win32_NetworkAdapter WHERE Manufacturer != 'Microsoft' AND (ConfigManagerErrorCode = 0 OR (ConfigManagerErrorCode = 22 AND NetConnectionStatus = 0))");// Final solution with filtering on the Manufacturer and PNPDeviceID not starting with "ROOT\"// Physical devices have PNPDeviceID starting with "PCI\" or something else besides "ROOT\"mos = new ManagementObjectSearcher(@"SELECT * FROM Win32_NetworkAdapter WHERE Manufacturer != 'Microsoft' AND NOT PNPDeviceID LIKE 'ROOT\\%'");// Get the physical adapters and sort them by their index. // This is needed because they're not sorted by defaultIList<ManagementObject> managementObjectList = mos.Get() .Cast<ManagementObject>() .OrderBy(p => Convert.ToUInt32(p.Properties["Index"].Value)) .ToList();// Let's just show all the properties for all physical adapters.foreach (ManagementObject mo in managementObjectList){ foreach (PropertyData pd in mo.Properties) Console.WriteLine(pd.Name + ": " + (pd.Value ?? "N/A"));}   That's it. Hope this helps you in some way.

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• SQL SERVER – Planned and Unplanned Availablity Group Failovers – Notes from the Field #031

  - by Pinal Dave

  [Note from Pinal]: This is a new episode of Notes from the Fields series. AlwaysOn is a very complex subject and not everyone knows many things about this. The matter of the fact is there is very little information available on this subject online and not everyone knows everything about this. This is why when a very common question related to AlwaysOn comes, people get confused. In this episode of the Notes from the Field series database expert John Sterrett (Group Principal at Linchpin People) explains a very common issue DBAs and Developer faces in their career and is related to Planned and Unplanned Availablity Group Failovers. Linchpin People are database coaches and wellness experts for a data driven world. Read the experience of John in his own words. Whenever a disaster occurs it will be a stressful scenario regardless of how small or big the disaster is. This gets multiplied when it is your first time working with newer technology or the first time you are going through a disaster without a proper run book. Today, were going to help you establish a run book for creating a planned failover with availability groups. To make today’s session simple were going to have two instances of SQL Server 2012 included in an availability group and walk through the steps of doing an unplanned failover.  We will focus on using the user interface and T-SQL to complete the failovers. We are going to use a two replica Availability Group where each replica is in another location. Therefore, we will be covering Asynchronous (non automatic failover) the following is a breakdown of our availability group utilized today. Seeing the following screen might be scary the first time you come across an unplanned failover.  It looks like our test database used in this Availability Group is not functional and it currently isn’t. The database status is not synchronizing which makes sense because the primary replica went down so it couldn’t synchronize. With that said, we can still failover and make it functional while we troubleshoot why we lost our primary replica. To start we are going to right click on the availability group that needs to be restarted and select failover. This will bring up the following wizard, which will walk you through several steps needed to complete the failover using the graphical user interface provided with SQL Server Management Studio (SSMS). You are going to see warning messages simply because we are in Asynchronous commit mode and can not guarantee ‘no data loss’ when we do failover. Just incase you missed it; you get another screen warning you about potential data loss because we are in Asynchronous mode. Next we get to connect to the specific replica we want to become the primary replica after the failover occurs. In our case, we only have two replicas so this is trivial. In order to failover, it’s required to connect to the replica that will become primary.  The following screen shows that the connection has been made successfully. Next, you will see the final summary screen. Once again, this reminds you that the failover action will cause data loss as were using Asynchronous commit mode due to the distance between instances used for disaster recovery. Finally, once the failover is completed you will see the following screen. If you followed along this long you might be wondering what T-SQL scripts are generated for clicking through all the sections of the wizard. If you have used Database Mirroring in the past you might be surprised.  It’s not too different, which makes sense because the data is being replicated via SQL Server endpoints just like the good old database mirroring. Now were going to take a look at how to do a failover with just T-SQL. First, were going to need to open a new query window and run our query in SQLCMD mode. Just incase you haven’t used SQLCMD mode before we will show you how to enable it below. Now you can run the following statement. Notice, we connect to the replica we want to become primary after failover and specify to force failover to allow data loss. We can use the following script to failback over when our primary instance comes back online. -- YOU MUST EXECUTE THE FOLLOWING SCRIPT IN SQLCMD MODE. :Connect SQL2012PROD1 ALTER AVAILABILITY GROUP [AGSQL2] FORCE_FAILOVER_ALLOW_DATA_LOSS; GO Are your servers running at optimal speed or are you facing any SQL Server Performance Problems? If you want to get started with the help of experts read more over here: Fix Your SQL Server. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Notes from the Field, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Passing the CAML thru the EY of the NEEDL

  - by PointsToShare

  © 2011 By: Dov Trietsch. All rights reserved Passing the CAML thru the EY of the NEEDL Definitions: CAML (Collaborative Application Markup Language) is an XML based markup language used in Microsoft SharePoint technologies  Anonymous: A camel is a horse designed by committee  Dov Trietsch: A CAML is a HORS designed by Microsoft  I was advised against putting any Camel and Sphinx rhymes in here. Look it up in Google!  _____ Now that we have dispensed with the dromedary jokes (BTW, I have many more, but they are not fit to print!), here is an interesting problem and its solution.  We have built a list where the title must be kept unique so I needed to verify the existence (or absence) of a list item with a particular title. Two methods came to mind:  1: Span the list until the title is found (result = found) or until the list ends (result = not found). This is an algorithm of complexity O(N) and for long lists it is a performance sucker. 2: Use a CAML query instead. Here, for short list we’ll encounter some overhead, but because the query results in an SQL query on the content database, it is of complexity O(LogN), which is significantly better and scales perfectly. Obviously I decided to go with the latter and this is where the CAML s--t hit the fan.   A CAML query returns a SPListItemCollection and I simply checked its Count. If it was 0, the item did not already exist and it was safe to add a new item with the given title. Otherwise I cancelled the operation and warned the user. The trouble was that I always got a positive. Most of the time a false positive. The count was greater than 0 regardles of the title I checked (except when the list was empty, which happens only once). This was very disturbing indeed. To solve my immediate problem which was speedy delivery, I reverted to the “Span the list” approach, but the problem bugged me, so I wrote a little console app by which I tested and tweaked and tested, time and again, until I found the solution. Yes, one can pass the proverbial CAML thru the ey of the needle (e’s missing on purpose).  So here are my conclusions:  CAML that does not work:  Note: QT is my quote:  char QT = Convert.ToChar((int)34); string titleQuery = "<Query>><Where><Eq>"; titleQuery += "<FieldRef Name=" + QT + "Title" + QT + "/>"; titleQuery += "<Value Type=" + QT + "Text" + QT + ">" + uniqueID + "</Value></Eq></Where></Query>"; titleQuery += "<ViewFields><FieldRef Name=" + QT + "Title" + QT + "/></ViewFields>";  Why? Even though U2U generates it, the <Query> and </Query> tags do not belong in the query that you pass. Start your query with the <Where> clause.  Also the <ViewFiels> clause does not belong. I used this clause to limit the returned collection to a single column, and I still wish to do it. I’ll show how this is done a bit later.   When you use the <Query> </Query> tags in you query, it’s as if you did not specify the query at all. What you get is the all inclusive default query for the list. It returns evey column and every item. It is expensive for both server and network because it does all the extra processing and eats plenty of bandwidth.   Now, here is the CAML that works  string titleQuery = "<Where><Eq>"; titleQuery += "<FieldRef Name=" + QT + "Title" + QT + "/>"; titleQuery += "<Value Type=" + QT + "Text" + QT + ">" + uniqueID + "</Value></Eq></Where>";  You’ll also notice that inside the unusable <ViewFields> clause above, we have a <FieldRef> clause. This is what we pass to the SPQuery object. Here is how:  SPQuery query = new SPQuery(); query.Query = titleQuery; query.ViewFields = "<FieldRef Name=" + QT + "Title" + QT + "/>"; query.RowLimit = 1; SPListItemCollection col = masterList.GetItems(query);  Two thing to note: we enter the view fields into the SPQuery object and we also limited the number of rows that the query returns. The latter is not always done, but in an existence test, there is no point in returning hundreds of rows. The query will now return one item or none, which is all we need in order to verify the existence (or non-existence) of items. Limiting the number of columns and the number of rows is a great performance enhancer. That’s all folks!!

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• Do You Develop Your PL/SQL Directly in the Database?

  - by thatjeffsmith

  I know this sounds like a REALLY weird question for many of you. Let me make one thing clear right away though, I am NOT talking about creating and replacing PLSQL objects directly into a production environment. Do we really need to talk about developers in production again? No, what I am talking about is a developer doing their work from start to finish in a development database. These are generally available to a development team for building the next and greatest version of your databases and database applications. And of course you are using a third party source control system, right? Last week I was in Tampa, FL presenting at the monthly Suncoast Oracle User’s Group meeting. Had a wonderful time, great questions and back-and-forth. My favorite heckler was there, @oraclenered, AKA Chet Justice.  I was in the middle of talking about how it’s better to do your PLSQL work in the Procedure Editor when Chet pipes up - Don’t do it that way, that’s wrong Just press play to edit the PLSQL directly in the database Or something along those lines. I didn’t get what the heck he was talking about. I had been showing how the Procedure Editor gives you much better feedback and support when working with PLSQL. After a few back-and-forths I got to what Chet’s main objection was, and again I’m going to paraphrase: You should develop offline in your SQL worksheet. Don’t do anything in the database until it’s done. I didn’t understand. Were developers expected to be able to internalize and mentally model the PL/SQL engine, see where their errors were, etc in these offline scripts? No, please give Chet more credit than that. What is the ideal Oracle Development Environment? If I were back in the ‘real world’ of database development, I would do all of my development outside of the ‘dev’ instance. My development process looks a little something like this: Do I have a program that already does something like this – copy and paste Has some smart person already written something like this – copy and paste Start typing in the white-screen-of-panic and bungle along until I get something that half-works Tweek, debug, test until I have fooled my subconscious into thinking that it’s ‘good’ As you might understand, I don’t want my co-workers to see the evolution of my code. It would seriously freak them out and I probably wouldn’t have a job anymore (don’t remind me that I already worked myself out of development.) So here’s what I like to do: Run a Local Instance of Oracle on my Machine and Develop My Code Privately I take a copy of development – that’s what source control is for afterall – and run it where no one else can see it. I now get to be my own DBA. If I need a trace – no problem. If I want to run an ASH report, no worries. If I need to create a directory or run some DataPump jobs, that’s all on me. Now when I get my code ‘up to snuff,’ then I will check it into source control and compile it into the official development instance. So my teammates suddenly go from seeing no program, to a mostly complete program. Is this right? If not, it doesn’t seem wrong to me. And after talking to Chet in the car on the way to the local cigar bar, it seems that he’s of the same opinion. So what’s so wrong with coding directly into a development instance? I think ‘wrong’ is a bit strong here. But there are a few pitfalls that you might want to look out for. A few come to mind – and I’m sure Chet could add many more as my memory fails me at the moment. But here goes: Development instance isn’t properly backed up – would hate to lose that work Development is wiped once a week and copied over from Prod – don’t laugh Someone clobbers your code You accidentally on purpose clobber someone else’s code The more developers you have in a single fish pond, the greater chance something ‘bad’ will happen This Isn’t One of Those Posts Where I Tell You What You Should Be Doing I realize many shops won’t be open to allowing developers to stage their own local copies of Oracle. But I would at least be aware that many of your developers are probably doing this anyway – with or without your tacit approval. SQL Developer can do local file tracking, but you should be using Source Control too! I will say that I think it’s imperative that you control your source code outside the database, even if your development team is comprised of a single developer. Store your source code in a file, and control that file in something like Subversion. You would be shocked at the number of teams that do not use a source control system. I know I continue to be shocked no matter how many times I meet another team running by the seat-of-their-pants. I’d love to hear how your development process works. And of course I want to know how SQL Developer and the rest of our tools can better support your processes. And one last thing, if you want a fun and interactive presentation experience, be sure to have Chet in the room

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• Exitus Acta Probat: The Post-Processing Module

  - by Phil Factor

  Sometimes, one has to make certain ethical compromises to ensure the success of a corporate IT project. Exitus Acta Probat (literally 'the result validates the deeds' meaning that the ends justify the means)It was a while back, whilst working as a Technical Architect for a well-known international company, that I was given the task of designing the architecture of a rather specialized accounting system. We'd tried an off-the-shelf (OTS) Windows-based solution which crashed with dispiriting regularity, and didn't quite do what the business required. After a great deal of research and planning, we commissioned a Unux-based system that used X-terminals for the desktops of  the participating staff. X terminals are now obsolete, but were then hot stuff; stripped-down Unix workstations that provided client GUIs for networked applications long before the days of AJAX, Flash, Air and DHTML. I've never known a project go so smoothly: I'd been initially rather nervous about going the Unix route, believing then that  Unix programmers were excitable creatures who were prone to  indulge in role-play enactments of elves and wizards at the weekend, but the programmers I met from the company that did the work seemed to be rather donnish, earnest, people who quickly grasped our requirements and were faultlessly professional in their work.After thinking lofty thoughts for a while, there was considerable pummeling of keyboards by our suppliers, and a beautiful robust application was delivered to us ahead of dates.Soon, the department who had commissioned the work received shiny new X Terminals to replace their rather depressing lavatory-beige PCs. I modestly hung around as the application was commissioned and deployed to the department in order to receive the plaudits. They didn't come. Something was very wrong with the project. I couldn't put my finger on the problem, and the users weren't doing any more than desperately and futilely searching the application to find a fault with it.Many times in my life, I've come up against a predicament like this: The roll-out of an application goes wrong and you are hearing nothing that helps you to discern the cause but nit-*** noise. There is a limit to the emotional heat you can pack into a complaint about text being in the wrong font, or an input form being slightly cramped, but they tried their best. The answer is, of course, one that every IT executive should have tattooed prominently where they can read it in emergencies: In Vino Veritas (literally, 'in wine the truth', alcohol loosens the tongue. A roman proverb) It was time to slap the wallet and get the department down the pub with the tab in my name. It was an eye-watering investment, but hedged with an over-confident IT director who relished my discomfort. To cut a long story short, The real reason gushed out with the third round. We had deprived them of their PCs, which had been good for very little from the pure business perspective, but had provided them with many hours of happiness playing computer-based minesweeper and solitaire. There is no more agreeable way of passing away the interminable hours of wage-slavery than minesweeper or solitaire, and the employees had applauded the munificence of their employer who had provided them with the means to play it. I had, unthinkingly, deprived them of it.I held an emergency meeting with our suppliers the following day. I came over big with the notion that it was in their interests to provide a solution. They played it cool, probably knowing that it was my head on the block, not theirs. In the end, they came up with a compromise. they would temporarily descend from their lofty, cerebral stamping grounds  in order to write a server-based Minesweeper and Solitaire game for X Terminals, and install it in a concealed place within the system. We'd have to pay for it, though. I groaned. How could we do that? "Could we call it a 'post-processing module?" suggested their account executive.And so it came to pass. The application was a resounding success. Every now and then, the staff were able to indulge in some 'post-processing', with what turned out to be a very fine implementation of both minesweeper and solitaire. There were several refinements: A single click in a 'boss' button turned the games into what looked just like a financial spreadsheet.  They even threw in a multi-user version of Battleships. The extra payment for the post-processing module went through the change-control process without anyone untoward noticing, and peace once more descended. Only one thing niggles. Those games were good. Do they still survive, somewhere in a Linux library? If so, I'd like to claim a small part in their production.

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• CLR via C# 3rd Edition is out

  - by Abhijeet Patel

  Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

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• Getting Started with Prism (aka Composite Application Guidance for WPF and Silverlight)

  - by dotneteer

  Overview Prism is a framework from the Microsoft Patterns and Practice team that allow you to create WPF and Silverlight in a modular way. It is especially valuable for larger projects in which a large number of developers can develop in parallel. Prism achieves its goal by supplying several services: · Dependency Injection (DI) and Inversion of control (IoC): By using DI, Prism takes away the responsibility of instantiating and managing the life time of dependency objects from individual components to a container. Prism relies on containers to discover, manage and compose large number of objects. By varying the configuration, the container can also inject mock objects for unit testing. Out of the box, Prism supports Unity and MEF as container although it is possible to use other containers by subclassing the Bootstrapper class. · Modularity and Region: Prism supplies the framework to split application into modules from the application shell. Each module is a library project that contains both UI and code and is responsible to initialize itself when loaded by the shell. Each window can be further divided into regions. A region is a user control with associated model. · Model, view and view-model (MVVM) pattern: Prism promotes the user MVVM. The use of DI container makes it much easier to inject model into view. WPF already has excellent data binding and commanding mechanism. To be productive with Prism, it is important to understand WPF data binding and commanding well. · Event-aggregation: Prism promotes loosely coupled components. Prism discourages for components from different modules to communicate each other, thus leading to dependency. Instead, Prism supplies an event-aggregation mechanism that allows components to publish and subscribe events without knowing each other. Architecture In the following, I will go into a little more detail on the services provided by Prism. Bootstrapper In a typical WPF application, application start-up is controls by App.xaml and its code behind. The main window of the application is typically specified in the App.xaml file. In a Prism application, we start a bootstrapper in the App class and delegate the duty of main window to the bootstrapper. The bootstrapper will start a dependency-injection container so all future object instantiations are managed by the container. Out of box, Prism provides the UnityBootstrapper and MefUnityBootstrapper abstract classes. All application needs to either provide a concrete implementation of one of these bootstrappers, or alternatively, subclass the Bootstrapper class with another DI container. A concrete bootstrapper class must implement the CreateShell method. Its responsibility is to resolve and create the Shell object through the DI container to serve as the main window for the application. The other important method to override is ConfigureModuleCatalog. The bootstrapper can register modules for the application. In a more advance scenario, an application does not have to know all its modules at compile time. Modules can be discovered at run time. Readers to refer to one of the Open Modularity Quick Starts for more information. Modules Once modules are registered with or discovered by Prism, they are instantiated by the DI container and their Initialize method is called. The DI container can inject into a module a region registry that implements IRegionViewRegistry interface. The module, in its Initialize method, can then call RegisterViewWithRegion method of the registry to register its regions. Regions Regions, once registered, are managed by the RegionManager. The shell can then load regions either through the RegionManager.RegionName attached property or dynamically through code. When a view is created by the region manager, the DI container can inject view model and other services into the view. The view then has a reference to the view model through which it can interact with backend services. Service locator Although it is possible to inject services into dependent classes through a DI container, an alternative way is to use the ServiceLocator to retrieve a service on demard. Prism supplies a service locator implementation and it is possible to get an instance of the service by calling: ServiceLocator.Current.GetInstance<IServiceType>() Event aggregator Prism supplies an IEventAggregator interface and implementation that can be injected into any class that needs to communicate with each other in a loosely-coupled fashion. The event aggregator uses a publisher/subscriber model. A class can publishes an event by calling eventAggregator.GetEvent<EventType>().Publish(parameter) to raise an event. Other classes can subscribe the event by calling eventAggregator.GetEvent<EventType>().Subscribe(EventHandler, other options). Getting started The easiest way to get started with Prism is to go through the Prism Hands-On labs and look at the Hello World QuickStart. The Hello World QuickStart shows how bootstrapper, modules and region works. Next, I would recommend you to look at the Stock Trader Reference Implementation. It is a more in depth example that resemble we want to set up an application. Several other QuickStarts cover individual Prism services. Some scenarios, such as dynamic module discovery, are more advanced. Apart from the official prism document, you can get an overview by reading Glen Block’s MSDN Magazine article. I have found the best free training material is from the Boise Code Camp. To be effective with Prism, it is important to understands key concepts of WPF well first, such as the DependencyProperty system, data binding, resource, theme and ICommand. It is also important to know your DI container of choice well. I will try to explorer these subjects in depth in the future. Testimony Recently, I worked on a desktop WPF application using Prism. I had a wonderful experience with Prism. The Prism is flexible enough even in the presence of third party controls such as Telerik WPF controls. We have never encountered any significant obstacle.

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