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• How to add class to openframeworks project in VS2012

  - by Mr Bell

  I am normally a C# guy but trying to get into c++. I made myself a new openframeworks project by copying and pasting one of the example projects and then renaming everything to my project name. (If there is an easier way, I would love to hear it) This project has the .cpp and .h files in a sub folder called "src" which are in turn organized into virtual folders (filters???) in visual studio. How can I add a class to this project from within visual studio? If I right click on the src filter in the solution explorer and hit add class. It creates the class files at the root of the project not in the src folder. I mean it does this both in the solution explorer and where it physically places the files. This is a problem because I can't include my class files in the rest of my app, presumably because they aren't in the same folder What is the proper way to add a class file?

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• seeing C# windows forms project code from F#

  - by Pessimist

  I have a C# Windows Forms project open with some C# code in it. Question: How can I have an F# file that I can write F# code in but still referencing all the C# code I have on Form1.cs (including the GUI). I can successfully do this: - Create a C# Windows Forms project - Create a F# Library project - Reference the F# Library DLL from my C# project - That way I can call F# functions from C# But I still can't see my buttons and textboxes from F# I understand that that is because it's a library and it can't reference System.Windows.Forms So how do I fix this? I don't want it to be a library or this or that, I just want it to be a file that will allow me to write F# code while being able to reference my C# Form and code. I guess you can say I want an F# file that is also a "partial class Form1" so that I can continue writing code for the same Project, but using F# instead. How do I do that?

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• Wrong assembly-references for Silverlight Sketchflow project in Blend 3

  - by persistent

  Hello, In my installation of Blend 3, the SketchStyles are missing when a new project is created. I found out that this is because the following automatic references in the project are wrong: Microsoft.Expression.Interactions Microsoft.Expression.Prototyping.Interactivity Microsoft.Expression.Prototyping.RunTime Microsoft.Expression.Prototyping.SketchControls In the project references these all point to my project path (where they don't live). If I remove them manually, and instead set the references to ie this: "c:\Program Files (x86)\Microsoft SDKs\Expression\Blend 3\Interactivity\Libraries\Silverlight\Microsoft.Expression.Interactions.dll" everything works. Any ideas on why, and how to fix this? Could it be the project template somehow? TIA

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• Data Integration/EAI Project Lessons Learned

  - by Greg Harman

  Have you worked on a significant data or application integration project? I'm interested in hearing what worked for you and what didn't and how that affected the project both during and after implementation (i.e. during ongoing operation, maintenance and expansion). In addition to these lessons learned, please describe the project by including a quick overview of: The data sources and targets. Specifics are not necessary, but I'd like to know general technology categories e.g. RDBMS table, application accessed via a proprietary socket protocol, web service, reporting tool. The overall architecture of the project as related to data flows. Different human roles in the project (was this all done by one engineer? Did it include analysts with a particular expertise?) Any third-party products utilized, commercial or open source.

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• Integrating a C project in the iPhone SDK

  - by iPhoneARguy

  Hello, This is my first time doing this sort of project so apologies if the question is silly. I've got a question about using a C project with a project in the iPhone SDK. I've dragged and dropped the C project into the iPhone project in Xcode (so it appears in the screenshot below). sjeng.h is a file inside GameEngine.xcodeproj, but when I try to include the header file, I not only receive an error, but the file it is looking for seems to be capitalized whereas the import statement is not. (I would post a screenshot but this is my first time doing something on stack overflow and I need more reputation points. The URL of the screenshot is here: http://imgur.com/AdrGL.png) Does anyone know what the problem might be? Thanks!

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• How to handle authenticated user access to resources in document oriented system?

  - by Jeremy Raymond

  I'm developing a document oriented application and need to manage user access to the documents. I have a module that handles user authentication, and another module that handles document CRUD operations on the data store. Once a user is authenticated I need to enforce what operations the user can and cannot perform to documents based upon the user's permissions. The best option I could think of to integrate these two pieces together would be to create another module that duplicates the data API but that also takes the authenticated user as a parameter. The module would delegate the authorization check to the auth module and delegate the document operation to the data access module. Something like: -module(auth_data_access). % User is authenticated (logged into the system) % save_doc validates if user is allowed to save the given document and if so % saves it returning ok, else returns {error, permission_denied} save_doc(Doc, User) -> case auth:save_allowed(Doc, User) of ok -> data_access:save_doc(Doc); denied -> {error, permission_denied} end end. Is there a better way I can handle this?

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• Visual Studio Custom Project Template

  - by rauts

  Hi All, I have created a Custom C# Project Template for Visual Studio 2008. It works perfect. Only issue is that i have to place the zip file for the project template under the "C:\Documents and Settings\\My Documents\Visual Studio 2008\Templates\ItemTemplates\Visual C#" Now as this folder is specific to each user on the machine, I will have to make sure that all the users on the machine has the project template installed seperately. Is there any way I can just install it once and all the users can get this project template. In short can I change the Custom Project template Install directory?

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• What ASP.NET MVC project files should I not add to Subversion

  - by Dan

  this is likely a naive question, but I want to do this right the first time. I have a MVC solution which has the following: Data project - C# Services project - C# MVC Web Project - ASP.NET MVC Test Project Currently, I am using the MVC2 source as a means to debug my own code. I do not plan on checking that in, but I realize once I go back to the MVC2 DLL, my solution will change. I'm pretty sure I just shouldn't check in stuff that changes with each build: the bin folder on the Web project, for example. Is there a list of what not to commit to source control? :)

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• c# use custom control directly in c# project

  - by PEEK

  hi ...hope someone can help me now: i want to use the listview flicker"less" control found here :http://geekswithblogs.net/CPound/archive/2006/02/27/70834.aspx directly in my c# Project.. i dont want to make a custom user control project, build it to dll and then import it in my project ..i just want this all in my c# Programm iam making.. i think i have to add in my project a class, and add the code, but how can i use the control now directly in my project? hope my problem is clear .. thanks for help

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• Django sys.path.append for project *and* app needed under WSGI

  - by GerardJP

  Hi all, Could somebody give me a pointer on why I need to add my project root path to the python path as well as the application itself in my WSGI file? Project base is called 'djapp', the application is called 'myapp'. sys.path.append(os.path.dirname(os.path.abspath(__file__)) + '/..') sys.path.append(os.path.dirname(os.path.abspath(__file__)) + '/../djapp') os.environ['DJANGO_SETTINGS_MODULE'] = 'djapp.settings' If I omit the line with "/../djapp/" the log tells my that 'myapp' can not be imported, even though 'djapp.settings' is. (validating 'djapp' was imported) It al runs properly with the ./manage.py command. there's a __init__ in the project folder. For testings sake, I see the same issue using addsitedir: site.addsitedir('/home/user/web/project/') site.addsitedir('/home/user/web/project/djapp') Thanx a lot. Gerard.

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• Is it possible to use dex2jar converted jar file into your project

  - by swapnil adsure

  i want to use ffmpeg decoder for my android project but i am having lots of error and config problem to compile it. but today i read about apk recompiling by dex2jar. so My question is " it is possible to use that dex2jar.jar file into your project ?. Like is it possible for me to use ffmpeg decoder into my project by importing that jar file into my project?. and same case with vitamio plugin . so if it is possible than i just need to add that plugin jar into my project and link with code and user dont need to download extra plugin. waiting for reply thank you

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• How to add "make install" target to simple Eclipse C project

  - by Jim Flood

  I have a simple Eclipse C project. Is there a way to add a "make install" target to the generated makefile? I can't seem to find the right search keywords to find any useful information in the doc or by googling (i.e. there is too much noise and no signal.) I tried creating a simple project using the autotools plug-in but without being able to find any useful doc or tutorial that starts from scratch with a single C source file, I couldn't even get the project to build. Edit: I'll take an answer based on using the autotools plug-in if I can get my project to build. I don't see how to add an include dir (-I) a link dir (-L) or additional link libs to a new Hello World autotools C project. Is there any simple autotools plug-in tutorial that covers this?

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• Adding files to the DPR file vs project paths in Delphi 2010

  - by Robert McCabe

  We are just migrating from D7 to D2010 and are having a debate about cleaning up the project paths. We have a number of directories with a large number of Pas files that are included on some project paths, but only a few of the files are actually used by any single project. One option is to eliminate the project paths completely and only have all used files in the dpr. The second option is to keep only the needed files in the dpr and have project paths to the directories for the rest of the files. Is there any argument for one option over the other?

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• Problems adding static library QT project

  - by Smek

  I have problems adding a static library to my Qt project. I have two project one is my static library and the other one is a Qt GUI project. As I add all classes to my GUI project as c++ or header files everything works just fine but I want this to be in a separate library. When I select the option to add a library I check External library then I select the .a file I have build and the folder where my header files can be found because I am working on a Mac I select Mac as the target platform. Then I click continue and then done. macx: LIBS += -L$$PWD/../../MyLib/build-MyLib-Desktop_Qt_5_2_1_clang_64bit-Debug/ -lMyLib INCLUDEPATH += $$PWD/../../MyLib/build-MyLib-Desktop_Qt_5_2_1_clang_64bit-Debug/include DEPENDPATH += $$PWD/../../MyLib/build-MyLib-Desktop_Qt_5_2_1_clang_64bit-Debug/include macx: PRE_TARGETDEPS += $$PWD/../../MyLib/build-MyLib-Desktop_Qt_5_2_1_clang_64bit-Debug/libMyLib.a When I build my GUI project I get the following error: The process "/usr/bin/make" exited with code 2. Can anyone tell me what the problem can be and how to resolve the problem? Thanks

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• Question about using an access database as a resource file in Visual Studio.

  - by user354303

  Hi I am trying to embed a Microsoft Access database file into my Class assembly DLL. I want my code to reference the resource file and use it with a ADODB.Connection object. Any body know a simpler way, or an easier way? Or what is wrong with my code, when i added the resource file it added me dataset definitions, but i have no idea what to do with those. The connection string I am trying below is from an automatically generated app.config. I did add the item as a resource... using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; using ConsoleApplication1.Resources;//SPPrinterLicenses using System.Data.OleDb; using ADODB; using System.Configuration; namespace ConsoleApplication1 { class SharePointPrinterManager { public static bool IsValidLicense(string HardwareID) { OleDbDataAdapter da = new OleDbDataAdapter(); DataSet ds = new DataSet(); ADODB.Connection adoCn = new Connection(); ADODB.Recordset adoRs = new Recordset(); //**open command below fails** adoCn.Open( @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Resources\SPPrinterLicenses.accdb;Persist Security Info=True", "", "", 1); adoRs.Open("Select * from AllWorkstationLicenses", adoCn, ADODB.CursorTypeEnum.adOpenForwardOnly, ADODB.LockTypeEnum.adLockReadOnly, 1); da.Fill(ds, adoRs, "AllworkstationLicenses"); adoCn.Close(); DataTable dt = new DataTable(); //ds.Tables. return true; } } }

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• Combining packages from different projects into a single project in eclipse

  - by primal

  Hi, As part of the Android application I am developing in eclipse, I need to combine two packages from different projects into a single project. I tried copying the files in the package of the second project under the src folder of the first folder and copied other files required for second package into the res folder of the first project. But the auto-generated Java files i.e R.java doesn't get updated on copying. I tried right clicking on the project and clicking on Android Tools - Fix Project Properties. But nothing changed. Any pointers on what I am doing wrong much be appreciated.

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• Publishing my project in Visual Basic

  - by Nora

  Hello, I developed a project using VB.Net and I used the following way to publish it: 1- Build - Build "my project" 2- Build - Publish "my project" then I follow the wizard and got the setup file at the end. But when I tried to install it I got an error telling me that my media files couldn't be found. ** I placed the media files in "Debug" folder inside "bin" folder. ** I'm using Microsoft Visual Basic 2008 Express Edition to develop this project. Is there any way to publish this project ?

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• Using Microsoft's Chart Controls In An ASP.NET Application: Serializing Chart Data

  In most usage scenarios, the data displayed in a Microsoft Chart control comes from some dynamic source, such as from a database query. The appearance of the chart can be modified dynamically, as well; past installments in this article series showed how to programmatically customize the axes, labels, and other appearance-related settings. However, it is possible to statically define the chart's data and appearance strictly through the control's declarative markup. One of the demos examined in the Getting Started article rendered a column chart with seven columns whose labels and values were defined statically in the <asp:Series> tag's <Points> collection. Given this functionality, it should come as no surprise that the Microsoft Chart Controls also support serialization. Serialization is the process of persisting the state of a control or an object to some other medium, such as to disk. Deserialization is the inverse process, and involves taking the persisted data and recreating the control or object. With just a few lines of code you can persist the appearance settings, the data, or both to a file on disk or to any stream. Likewise, it takes just a few lines of codes to reconstitute a chart from the persisted information. This article shows how to use the Microsoft Chart Control's serialization functionality by examining a demo application that allows users to create custom charts, specifying the data to plot and some appearance-related settings. The user can then save a "snapshot" of this chart, which persists its appearance and data to a record in a database. From another page, users can view these saved chart snapshots. Read on to learn more! Read More >

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• Want a headless build server for SSDT without installing Visual Studio? You’re out of luck!

  - by jamiet

  An issue that regularly seems to rear its head on my travels is that of headless build servers for SSDT. What does that mean exactly? Let me give you my interpretation of it. A SQL Server Data Tools (SSDT) project incorporates a build process that will basically parse all of the files within the project and spit out a .dacpac file. Where an organisation employs a Continuous Integration process they will likely want to automate the building of that dacpac whenever someone commits a change to the source control repository. In order to do that the organisation will use a build server (e.g. TFS, TeamCity, Jenkins) and hence that build server requires all the pre-requisite software that understands how to build an SSDT project. The simplest way to install all of those pre-requisites is to install SSDT itself however a lot of folks don’t like that approach because it installs a lot unnecessary components on there, not least Visual Studio itself. Those folks (of which i am one) are of the opinion that it should be unnecessary to install a heavyweight GUI in order to simply get a few software components required to do something that inherently doesn’t even need a GUI. The phrase “headless build server” is often used to describe a build server that doesn’t contain any heavyweight GUI tools such as Visual Studio and is a desirable state for a build server. In his blog post Headless MSBuild Support for SSDT (*.sqlproj) Projects Gert Drapers outlines the steps necessary to obtain a headless build server for SSDT: This article describes how to install the required components to build and publish SQL Server Data Tools projects (*.sqlproj) using MSBuild without installing the full SQL Server Data Tool hosted inside the Visual Studio IDE. http://sqlproj.com/index.php/2012/03/headless-msbuild-support-for-ssdt-sqlproj-projects/ Frankly however going through these steps is a royal PITA and folks like myself have longed for Microsoft to support headless build support for SSDT by providing a distributable installer that installs only the pre-requisites for building SSDT projects. Yesterday in MSDN forum thread Building a VS2013 headless build server - it's sooo hard Mike Hingley complained about this very thing and it prompted a response from Kevin Cunnane from the SSDT product team: The official recommendation from the TFS / Visual Studio team is to install the version of Visual Studio you use on the build machine. I, like many others, would rather not have to install full blown Visual Studio and so I asked: Is there any chance you'll ever support any of these scenarios: Installation of all build/deploy pre-requisites without installing the VS shell? TFS shipping with all of the pre-requisites for doing SSDT project build/deploys 3rd party build servers (e.g. TeamCity) shipping with all of the requisites for doing SSDT project build/deploys I have to say that the lack of a single installer containing all the pre-requisites for SSDT build/deploy puzzles me. Surely the DacFX installer would be a perfect vehicle for that? Kevin replied again: The answer is no for all 3 scenarios. We looked into this issue, discussed it with the Visual Studio / TFS team, and in the end agreed to go with their latest guidance which is to install Visual Studio (e.g. VS2013 Express for Web) on the build machine. This is how Visual Studio Online is doing it and it's the approach recommended for customers setting up their own TFS build servers. I would hope this is compatible with 3rd party build servers but have not verified whether this works with TeamCity etc. Note that DacFx MSI isn't a suitable release vehicle for this as we don't want to include Visual Studio/MSBuild dependencies in that package. It's meant to just include the core DacFx DLLs used by SSMS, SqlPackage.exe on the command line, etc. What this means is we won't be providing a separate MSI installer or nuget package with just the necessary build DLLs you need to run your build and tests. If someone wanted to create a script that generated a nuget package based on our DLLs and targets files, then release that somewhere on the web for easier integration with 3rd party build servers we've no problem with that. Again, here’s the link to the thread and its worth reading in its entirety if this is something that interests you. So there you have it. Microsoft will not be be providing support for headless build servers for SSDT but if someone in the community wants to go ahead and roll their own, go right ahead. @Jamiet

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• Oracle Database Security Protecting the Oracle IRM Schema

  - by Simon Thorpe

  Acquiring the Information Rights Management technology in 2006 was part of Oracle's strategic security vision and IRM compliments nicely the overall Oracle security set of solutions. A year ago I spoke about how Oracle has solutions that can help companies protect information throughout its entire life cycle. With our acquisition of Sun this set of solutions has solidified and has even extended down to the operating system and hardware level. Oracle can now offer customers technology that protects their data from the disk, through the database to documents on the desktop! With the recent release of Oracle IRM 11g I was tasked to configure demonstration and evaluation environments and I thought it would make a nice story to leverage some of the security features in the latest release of the Oracle Database. After building these environments I thought I would put together a simple video demonstrating how both Database Advanced Security and Information Rights Management combined can provide a very secure platform for protecting your information. Have a look at the following which highlights these database security options.Transparent Data Encryption protecting the communication from the Oracle IRM server to the Database server. Encryption techniques provide confidentiality and integrity of the data passing to and from the IRM service on the back end. Transparent Data Encryption protecting the Oracle IRM database schema. Encryption is used to provide confidentiality of the IRM data whilst it resides at rest in the database table space. Database Vault is used to ensure only the Oracle IRM service has access to query and update the information that resides in the database. This is an excellent method of ensuring that database administrators cannot look at or make changes to the Oracle IRM database whilst retaining their ability to administrate the database. The last thing you want after deploying an IRM solution is for a curious or unhappy DBA to run a query that grants them rights to your company financial data or documents pertaining to a merger or acquisition.

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• Join our webcast: Discover What’s New in Oracle Data Integrator and Oracle GoldenGate

  - by Irem Radzik

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman";} Data integration team has organized a series of webcasts for this summer. We are kicking it off this Thursday June 30th at 10am PT with a product update webcast: Discover What’s New in Oracle Data Integrator and Oracle GoldenGate. In this webcast you will hear from product management about the new patch updates to both GoldenGate 11g R1 and ODI 11gR1. Jeff Pollock, Sr. Director of Product Management for ODI will talk about the new features in Oracle Data Integrator 11.1.1.5, including the data lineage integration with OBI EE, enhanced web services to support flexible architectures as well as capabilities for efficient object execution such as Load Plans. Jeff will discuss support for complex files and performance enhancements. Chris McAllister, Sr. Director of Product Management for Oracle GoldenGate will cover the new features of Oracle GoldenGate 11.1.1.1 such as increased data security by supporting Oracle Database Advanced Security option, deeper integration with Oracle Database, and the expanded list of heterogeneous databases GoldenGate supports . Chris will also talk about the new Oracle GoldenGate 11gR1 release for HP NonStop platform and will provide information on our strategic direction for product development. Join us this Thursday at 10am PT/ 1pm ET to hear directly from Data Integration Product Management . You can register here for the June 30th webcast as well as for the upcoming ones in our summer webcast series.

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• SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

  - by pinaldave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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• Announcing Sesame Data Browser

  - by Fabrice Marguerie

  At the occasion of MIX10, which is currently taking place in Las Vegas, I'd like to announce Sesame Data Browser.Sesame will be a suite of tools for dealing with data, and Sesame Data Browser will be the first tool from that suite.Today, during the second MIX10 keynote, Microsoft demonstrated how they are pushing hard to get OData adopted. If you don't know about OData, you can visit the just revamped dedicated website: http://odata.org. There you'll find about the OData protocol, which allows you to publish and consume data on the web, the OData SDK (with client libraries for .NET, Java, Javascript, PHP, iPhone, and more), a list of OData producers, and a list of OData consumers.This is where Sesame Data Browser comes into play. It's one of the tools you can use today to consume OData.I'll let you have a look, but be aware that this is just a preview and many additional features are coming soon.Sesame Data Browser is part of a bigger picture than just OData that will take shape over the coming months. Sesame is a project I've been working on for many months now, so what you see now is just a start :-)I hope you'll enjoy what you see. Let me know what you think.

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• Methodology behind fetching large XML data sets in pieces

  - by Jerry Dodge

  I am working on an HTTP Server in Delphi which simply sends back a custom XML dataset. I am not following any type of standard formatting, such as SOAP. I have the system working seamlessly, except one small flaw: When I have a very large dataset to send back to the client, it might take up to 2 minutes for all the data to be transferred. The HTTP Server I'm building is essentially an XML Data based API around a database, implementing the common business rule - therefore, the requests are specific to the data behind the system. When, for example, I fetch a large set of product data, I would like to break this down and send it back piece by piece. However, a single HTTP request calls for a single response. I can't necessarily keep feeding the client with multiple different XML packets unless the client explicitly requests it. I don't have any session management, but rather an API Key. I know if I had sessions, I could keep-alive a dataset temporarily for a client, and they could request bits and pieces of it. However, without session management, I would have to execute the SQL query multiple times (for each chunk of data), and in the mean-time, if that data changes, the "pages" might get messed up, therefore causing items to show on the wrong pages, after navigating to a different page. So how is this commonly handled? What's the methodology behind breaking down a large XML dataset into chunks to save the load?

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• Using Microsoft's Chart Controls In An ASP.NET Application: Serializing Chart Data

  In most usage scenarios, the data displayed in a Microsoft Chart control comes from some dynamic source, such as from a database query. The appearance of the chart can be modified dynamically, as well; past installments in this article series showed how to programmatically customize the axes, labels, and other appearance-related settings. However, it is possible to statically define the chart's data and appearance strictly through the control's declarative markup. One of the demos examined in the Getting Started article rendered a column chart with seven columns whose labels and values were defined statically in the <asp:Series> tag's <Points> collection. Given this functionality, it should come as no surprise that the Microsoft Chart Controls also support serialization. Serialization is the process of persisting the state of a control or an object to some other medium, such as to disk. Deserialization is the inverse process, and involves taking the persisted data and recreating the control or object. With just a few lines of code you can persist the appearance settings, the data, or both to a file on disk or to any stream. Likewise, it takes just a few lines of codes to reconstitute a chart from the persisted information. This article shows how to use the Microsoft Chart Control's serialization functionality by examining a demo application that allows users to create custom charts, specifying the data to plot and some appearance-related settings. The user can then save a "snapshot" of this chart, which persists its appearance and data to a record in a database. From another page, users can view these saved chart snapshots. Read on to learn more! Read More >

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