Search Results

Search found 28459 results on 1139 pages for 'task base programming'.

Page 1/1139 | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

  • Task scheduler "hidden" only hides task, not process

    - by Brandi
    I am trying to make an application that acts like a desktop application for all the computers in our network. I have already got a windows forms app that works like I want it to, and I'm using the task scheduler to start it on login. We would really like it if the process as well as the task is hidden from the task manager in order to avoid accidental deletion. Selecting "Hidden" in the task scheduler hides the task (good!) but the process is still visible (not good enough). I tried using the option to run as "SYSTEM" or "LOCAL SERVICE" so that the user would get "access denied" when trying to delete or just wouldn't even view it by default. However, running as a service makes the process invisible on Vista and 7, and the point of my app is to display information interactively. (User can click, sort, etc). Is there any other alternatives to either run the process as someone/something besides the logged in user and still have the logged on user be able to see and interact with it? (Therefore it would list as someone else's app?) From what I've read on the internet, the only ways to actually hide something from the task manager seem hacky and/or difficult and rather involved. I don't really want to write a bunch of C or whatever only to maybe not have it work on Vista/7 anyway. Besides which, for a legitimate app with a legitimate use, I shouldn't have to go to those extremes... I see "Access Denied" all the time for system processes... why is it so hard for me to do the same? So does anyone have any simple solutions? Is it easier than I think to just list something in the task manager as another user? Thanks in advance for any replies.

    Read the article

  • The Best Free Alternatives to the Windows Task Manager

    - by Lori Kaufman
    The Windows Task Manager is a built-in tool that allows you to check which services are running in the background, how much resources are being used by which software programs, and the all-to-common task of killing programs that are not responding. Even though the Windows Task Manager has several useful tools, there are many free alternatives available that provide additional or expanded features, allowing you to more closely monitor and tweak your system. How To Play DVDs on Windows 8 6 Start Menu Replacements for Windows 8 What Is the Purpose of the “Do Not Cover This Hole” Hole on Hard Drives?

    Read the article

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

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

    Read the article

  • Windows Server 2008 Task Scheduler Tasks Not Executing

    - by omatase
    I've been having an intermittent problem for some time now with the Windows Task Scheduler that I can't work out. I use the task scheduler to run a C# app I've written that has various plugins used to ensure production systems are working. This task scheduler itself is actually a production system so I have one simple task that executes every 8 minutes to notify an external monitoring system that the task scheduler is still up. If this external service fails to receive an "all-clear" at least once every 15 minutes (or so I don't remember the exact number right now) it will message us that the monitoring system is down. In the past we've had intermittent "down" messages from time to time and each time I've investigated the cause I was unable to find any problems. So this time I wanted to ask the StackOverflow community since it doesn't look like I'll have luck on my own. This morning at 2:32 AM the task fired (exactly 8 minutes after the previous firing) however the task didn't fire again until 3:28. There are no errors that I can see in the Event Viewer at this time. When I look at the Task Scheduler log there are no errors there either. Here is what the log looks like though: Information 6/11/2011 3:28:56 AM 102 Task completed (2) d6cf2412-269e-48bf-9f40-4a863347baad Information 6/11/2011 3:28:56 AM 201 Action completed (2) d6cf2412-269e-48bf-9f40-4a863347baad Information 6/11/2011 3:28:55 AM 129 Created Task Process Info Information 6/11/2011 3:28:55 AM 200 Action started (1) d6cf2412-269e-48bf-9f40-4a863347baad Information 6/11/2011 3:28:55 AM 100 Task Started (1) d6cf2412-269e-48bf-9f40-4a863347baad Information 6/11/2011 3:28:55 AM 319 Task Engine received message to start task (1) Information 6/11/2011 3:28:55 AM 107 Task triggered on scheduler Info d6cf2412-269e-48bf-9f40-4a863347baad Information 6/11/2011 3:28:15 AM 102 Task completed (2) b91fe5ce-39ef-42fb-adbe-bd8be012c00a Information 6/11/2011 3:28:15 AM 201 Action completed (2) b91fe5ce-39ef-42fb-adbe-bd8be012c00a Information 6/11/2011 3:28:15 AM 102 Task completed (2) 556c07dc-2724-4a21-a97e-dc4abd56f94d Information 6/11/2011 3:28:15 AM 201 Action completed (2) 556c07dc-2724-4a21-a97e-dc4abd56f94d Information 6/11/2011 3:28:15 AM 102 Task completed (2) 79328289-f742-49dd-aa0d-c3d05db50895 Information 6/11/2011 3:28:15 AM 201 Action completed (2) 79328289-f742-49dd-aa0d-c3d05db50895 Information 6/11/2011 3:28:15 AM 102 Task completed (2) 19743755-47b6-4b98-9bec-052193be9496 Information 6/11/2011 3:28:15 AM 201 Action completed (2) 19743755-47b6-4b98-9bec-052193be9496 Information 6/11/2011 3:28:15 AM 102 Task completed (2) c165754f-e3e6-4176-a327-11f9c06c39a5 Information 6/11/2011 3:28:15 AM 201 Action completed (2) c165754f-e3e6-4176-a327-11f9c06c39a5 Information 6/11/2011 3:28:15 AM 102 Task completed (2) 0e62ad3e-1f6e-40c0-9155-19f0108dee22 Information 6/11/2011 3:28:15 AM 201 Action completed (2) 0e62ad3e-1f6e-40c0-9155-19f0108dee22 Information 6/11/2011 3:28:10 AM 129 Created Task Process Info Information 6/11/2011 3:28:10 AM 200 Action started (1) 0e62ad3e-1f6e-40c0-9155-19f0108dee22 Information 6/11/2011 3:28:10 AM 129 Created Task Process Info Information 6/11/2011 3:28:10 AM 200 Action started (1) c165754f-e3e6-4176-a327-11f9c06c39a5 Information 6/11/2011 3:28:10 AM 129 Created Task Process Info Information 6/11/2011 3:28:10 AM 200 Action started (1) 19743755-47b6-4b98-9bec-052193be9496 Information 6/11/2011 3:28:10 AM 129 Created Task Process Info Information 6/11/2011 3:28:10 AM 200 Action started (1) 79328289-f742-49dd-aa0d-c3d05db50895 Information 6/11/2011 3:28:10 AM 129 Created Task Process Info Information 6/11/2011 3:28:10 AM 200 Action started (1) 556c07dc-2724-4a21-a97e-dc4abd56f94d Information 6/11/2011 3:28:10 AM 129 Created Task Process Info Information 6/11/2011 3:28:10 AM 200 Action started (1) b91fe5ce-39ef-42fb-adbe-bd8be012c00a Information 6/11/2011 3:28:10 AM 100 Task Started (1) 0e62ad3e-1f6e-40c0-9155-19f0108dee22 Information 6/11/2011 3:28:10 AM 319 Task Engine received message to start task (1) Information 6/11/2011 3:28:10 AM 100 Task Started (1) c165754f-e3e6-4176-a327-11f9c06c39a5 Information 6/11/2011 3:28:10 AM 319 Task Engine received message to start task (1) Information 6/11/2011 3:28:10 AM 100 Task Started (1) 19743755-47b6-4b98-9bec-052193be9496 Information 6/11/2011 3:28:10 AM 319 Task Engine received message to start task (1) Information 6/11/2011 3:28:10 AM 100 Task Started (1) 79328289-f742-49dd-aa0d-c3d05db50895 Information 6/11/2011 3:28:10 AM 319 Task Engine received message to start task (1) Information 6/11/2011 3:28:10 AM 100 Task Started (1) 556c07dc-2724-4a21-a97e-dc4abd56f94d Information 6/11/2011 3:28:10 AM 319 Task Engine received message to start task (1) Information 6/11/2011 3:28:10 AM 100 Task Started (1) b91fe5ce-39ef-42fb-adbe-bd8be012c00a Information 6/11/2011 3:28:10 AM 319 Task Engine received message to start task (1) Information 6/11/2011 3:28:10 AM 107 Task triggered on scheduler Info 0e62ad3e-1f6e-40c0-9155-19f0108dee22 Information 6/11/2011 3:28:10 AM 107 Task triggered on scheduler Info c165754f-e3e6-4176-a327-11f9c06c39a5 Information 6/11/2011 3:28:10 AM 107 Task triggered on scheduler Info 19743755-47b6-4b98-9bec-052193be9496 Information 6/11/2011 3:28:10 AM 107 Task triggered on scheduler Info 79328289-f742-49dd-aa0d-c3d05db50895 Information 6/11/2011 3:28:10 AM 107 Task triggered on scheduler Info 556c07dc-2724-4a21-a97e-dc4abd56f94d Information 6/11/2011 3:28:10 AM 107 Task triggered on scheduler Info b91fe5ce-39ef-42fb-adbe-bd8be012c00a Information 6/11/2011 2:32:56 AM 102 Task completed (2) 16e4f2c3-a340-410a-9c14-4bfe0861fdd5 Information 6/11/2011 2:32:56 AM 201 Action completed (2) 16e4f2c3-a340-410a-9c14-4bfe0861fdd5 Information 6/11/2011 2:32:55 AM 129 Created Task Process Info Information 6/11/2011 2:32:55 AM 200 Action started (1) 16e4f2c3-a340-410a-9c14-4bfe0861fdd5 Information 6/11/2011 2:32:55 AM 100 Task Started (1) 16e4f2c3-a340-410a-9c14-4bfe0861fdd5 Information 6/11/2011 2:32:55 AM 319 Task Engine received message to start task (1) Information 6/11/2011 2:32:55 AM 107 Task triggered on scheduler Info 16e4f2c3-a340-410a-9c14-4bfe0861fdd5 Seems kind of strange. I also have two other C# apps that run and check something each hour on the hour using task scheduler. If I look at the history for those I can see that they didn't execute at 3 AM either! They all waited until 3:28 to start as well. If I look at "tasks completed" in the Event Viewer it shows that only one task was able to run between the 2:32 AM to 3:28 AM time period. The task was "\Microsoft\Windows\RAC\RACAgent" And here's what it looked like: Information 6/11/2011 3:18:09 AM 102 Task completed (2) 00c53a85-ba20-4666-80db-fbbe2492c0ad Information 6/11/2011 3:18:09 AM 201 Action completed (2) 00c53a85-ba20-4666-80db-fbbe2492c0ad Information 6/11/2011 3:18:08 AM 129 Created Task Process Info Information 6/11/2011 3:18:08 AM 200 Action started (1) 00c53a85-ba20-4666-80db-fbbe2492c0ad Information 6/11/2011 3:18:08 AM 100 Task Started (1) 00c53a85-ba20-4666-80db-fbbe2492c0ad Information 6/11/2011 3:18:08 AM 319 Task Engine received message to start task (1) I appreciate any ideas anyone may have.

    Read the article

  • Letters in base-conversion

    - by tech_geek23
    I have this code written so far and is correct, aside from not using A-F when the value is over 10: public class TenToAny { private int base10; private int newBase; public TenToAny() { } public TenToAny(int ten, int base) { base10 = ten; newBase = base; } public void setNums(int ten, int base) { base10 = ten; newBase = base; } public String getNewNum() { String newNum=""; int orig = base10; //int first = newBase - 1; while(orig > 0) { newNum = orig%newBase + newNum; orig = orig/newBase; } return newNum; } public String toString() { String complete = base10 + " base 10 is " + getNewNum() + " in base " + newBase; return complete; } } Obviously I don't have anything relating to values over 10 converting to A-F as I've never dealt with these before. Any help is appreciated. Here's my runner class: public class Lab09i { public static void main( String args[] ) { TenToAny test = new TenToAny(234, 9); out.println(test); test.setNums(100, 2); out.println(test); test.setNums(10, 2); out.println(test); test.setNums(15, 2); out.println(test); test.setNums(256, 2); out.println(test); test.setNums(100, 8); out.println(test); test.setNums(250, 16); out.println(test); test.setNums(56, 11); out.println(test); test.setNums(89, 5); out.println(test); test.setNums(23, 3); out.println(test); test.setNums(50, 5); out.println(test); test.setNums(55, 6); out.println(test); test.setNums(2500, 6); out.println(test); test.setNums(2500, 13); out.println(test); } } this is what my results should be: 234 base 10 is 280 in base 9 100 base 10 is 1100100 in base 2 10 base 10 is 1010 in base 2 15 base 10 is 1111 in base 2 256 base 10 is 100000000 in base 2 100 base 10 is 144 in base 8 250 base 10 is FA in base 16 56 base 10 is 51 in base 11 89 base 10 is 324 in base 5 23 base 10 is 212 in base 3 50 base 10 is 302 in base 4 55 base 10 is 131 in base 6 2500 base 10 is 9C4 in base 16 2500 base 10 is 11A4 in base 13

    Read the article

  • What's The Difference Between Imperative, Procedural and Structured Programming?

    - by daniels
    By researching around (books, Wikipedia, similar questions on SE, etc) I came to understand that Imperative programming is one of the major programming paradigms, where you describe a series of commands (or statements) for the computer to execute (so you pretty much order it to take specific actions, hence the name "imperative"). So far so good. Procedural programming, on the other hand, is a specific type (or subset) of Imperative programming, where you use procedures (i.e., functions) to describe the commands the computer should perform. First question: Is there an Imperative programming language which is not procedural? In other words, can you have Imperative programming without procedures? Update: This first question seems to be answered. A language CAN be imperative without being procedural or structured. An example is pure Assembly language. Then you also have Structured programming, which seems to be another type (or subset) of Imperative programming, which emerged to remove the reliance on the GOTO statement. Second question: What is the difference between procedural and structured programming? Can you have one without the other, and vice-versa? Can we say procedural programming is a subset of structured programming, as in the image?

    Read the article

  • Windows Task Scheduler fails on EventData instruction

    - by Pete
    The Scheduled Task fails on the Event Data instruction in this XML: <ValueQueries> <Value name="eventChannel">Event/System/Channel</Value> <Value name="eventRecordID">Event/System/EventRecordID</Value> <Value name="eventData">Event/EventData/Data</Value> </ValueQueries> The other 2 fields can be passed as arguments and the EventData syntax matches other websites, so I don't know why it's failing. This is the Event Viewer XML: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Aptify.ExceptionManagerPublishedException" /> <EventID Qualifiers="0">0</EventID> <Level>2</Level> <Task>0</Task> <Keywords>0x80000000000000</Keywords> <TimeCreated SystemTime="2013-11-07T19:39:14.000000000Z" /> <EventRecordID>97555</EventRecordID> <Channel>Application</Channel> <Computer>[Computer Name]</Computer> <Security /> </System> <EventData> <Data>General Information ********************************************* Additional Info: ExceptionManager.MachineName: [Computer Name] ExceptionManager.TimeStamp: 11/7/2013 12:39:14 PM ExceptionManager.FullName: AptifyExceptionManagement, Version=4.0.0.0, Culture=neutral, PublicKeyToken=[key] ExceptionManager.AppDomainName: Aptify Shell.exe ExceptionManager.ThreadIdentity: ExceptionManager.WindowsIdentity: ACA_DOMAIN\pbassett 1) Exception Information ********************************************* Exception Type: Aptify.Framework.BusinessLogic.GenericEntity.AptifyGenericEntityValidationException Entity: Tasks ErrorString: Task Type "Make Contact" is not active. MachineName: [machine] CreatedDateTime: 11/7/2013 12:39:14 PM AppDomainName: Aptify Shell.exe ThreadIdentityName: WindowsIdentityName: [identity] Severity: 0 ErrorNumber: 0 Message: Task Type "Make Contact" is not active. Data: System.Collections.ListDictionaryInternal TargetSite: Boolean Save(Boolean, System.String ByRef, Sys tem.String) HelpLink: NULL Source: AptifyGenericEntity StackTrace Information ********************************************* at Aptify.Framework.BusinessLogic.GenericEntity.AptifyGenericEntity.Save(Boolean AllowGUI, String& ErrorString, String TransactionID)</Data> </EventData> </Event>

    Read the article

  • Task scheduler ran a task twice

    - by Ross Buggins
    Update: This has now happened two days in a row. Update: XML of scheduled tasks and images now included. Two servers located in London, both Windows 2012, have a scheduled task set to run at 3pm Monday to Friday. This has been set up for the last 5 months without a problem. However, on Monday the 28th of August they both ran the scheduled task at 3pm and then again at 4pm. When it was first reported, I thought it was too much of a coincidence to be the day after the clocks had gone back an hour. However, I’m failing in being able to explain why it has happened and if it is related to the clock change at all. The relevant logs from one server (the logs for the other follow this pattern as well): Event 129 15:00:20 Task Scheduler launch task "\3pm", instance "C:\Program Files (x86)\PHP\v5.4\php.exe" with process ID 2388. Event 100 15:00:20 Task Scheduler started "{75a3590f-dec1-4dee-bd27-73d63a50a9d7}" instance of the "\3pm" task for user "x\y". Event 200 15:00:20 Task Scheduler launched action "C:\Program Files (x86)\PHP\v5.4\php.exe" in instance "{75a3590f-dec1-4dee-bd27-73d63a50a9d7}" of task "\3pm". Event 201 15:00:23 Task Scheduler successfully completed task "\3pm" , instance "{75a3590f-dec1-4dee-bd27-73d63a50a9d7}" , action "C:\Program Files (x86)\PHP\v5.4\php.exe" with return code 0. Event 129 16:00:20 Task Scheduler launch task "\3pm", instance "C:\Program Files (x86)\PHP\v5.4\php.exe" with process ID 1224. Event 100 16:00:20 Task Scheduler started "{3dd46ca9-c525-4796-86b5-5e513fd45f26}" instance of the "\3pm" task for user "x\y". Event 200 16:00:20 Task Scheduler launched action "C:\Program Files (x86)\PHP\v5.4\php.exe" in instance "{3dd46ca9-c525-4796-86b5-5e513fd45f26}" of task "\3pm". Event 201 16:00:23 Task Scheduler successfully completed task "\3pm" , instance "{3dd46ca9-c525-4796-86b5-5e513fd45f26}" , action "C:\Program Files (x86)\PHP\v5.4\php.exe" with return code 0. I've seen this question Scheduled task running twice from time to time which points to a bug at http://support.microsoft.com/kb/2461249 being the cause. However, this doesn't include Server 2012 in it's list of problem operating systems. I’m struggling to explain this, can anyone else? The XML export for the scheduled task is: <?xml version="1.0" encoding="UTF-16"?> <Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task"> <RegistrationInfo> <Date>2013-04-16T14:04:17.4897806</Date> <Author>x\y</Author> </RegistrationInfo> <Triggers> <CalendarTrigger> <StartBoundary>2013-04-17T15:00:20</StartBoundary> <Enabled>true</Enabled> <ScheduleByWeek> <DaysOfWeek> <Monday /> <Tuesday /> <Wednesday /> <Thursday /> <Friday /> </DaysOfWeek> <WeeksInterval>1</WeeksInterval> </ScheduleByWeek> </CalendarTrigger> </Triggers> <Principals> <Principal id="Author"> <UserId>x\y</UserId> <LogonType>Password</LogonType> <RunLevel>LeastPrivilege</RunLevel> </Principal> </Principals> <Settings> <MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy> <DisallowStartIfOnBatteries>true</DisallowStartIfOnBatteries> <StopIfGoingOnBatteries>true</StopIfGoingOnBatteries> <AllowHardTerminate>true</AllowHardTerminate> <StartWhenAvailable>false</StartWhenAvailable> <RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable> <IdleSettings> <StopOnIdleEnd>true</StopOnIdleEnd> <RestartOnIdle>false</RestartOnIdle> </IdleSettings> <AllowStartOnDemand>true</AllowStartOnDemand> <Enabled>true</Enabled> <Hidden>false</Hidden> <RunOnlyIfIdle>false</RunOnlyIfIdle> <WakeToRun>false</WakeToRun> <ExecutionTimeLimit>P3D</ExecutionTimeLimit> <Priority>7</Priority> </Settings> <Actions Context="Author"> <Exec> <Command>"C:\Program Files (x86)\PHP\v5.4\php.exe"</Command> <Arguments>-f "c:\a.php"</Arguments> </Exec> </Actions> </Task> 29 October 17:00 - Update - Both servers have again run the scheduled task at 15:00 and 16:00. I've now updated the php file that is run by the scheduler to not actually do anything whilst I'm going through trying to solve this. I'm planning on restarting one server to see if this changes anything tomorrow. 30 October 08:25 - Update - When exporting the task XML I remembered that I hadn't included the fact that the scheduled task on second server was created by importing the XML of the task created on the first. The only difference between the two tasks is the path of the php file they are executing and the user account that they are running as.

    Read the article

  • Windows Server 2008 Task Scheduler: Task Started (Task=100) but did task did not complete (Task=102) when the result code is 2

    - by MacGyver
    Can someone give me a use case for setting up a Windows Server 2008 Task Scheduler task (we'll call this "test") that completes (action completed is task=201) with an error (result code=2)? This is event trigger code for another task (called "notification" that sends out an email based on the event history of the "test" task. I've got use cases for tasks that opens a program successfully and when a program fails to find the program. I'm just trying to think of how I can test a scenario when it finds the program, but something fails with warnings or errors. /* Failed - task started but had errors (result code of 2) */ <QueryList> <Query Id="0" Path="Microsoft-Windows-TaskScheduler/Operational"> <Select Path="Microsoft-Windows-TaskScheduler/Operational"> *[ System [ Provider[@Name='Microsoft-Windows-TaskScheduler'] and (Level=0 or Level=1 or Level=2 or Level=3 or Level=4 or Level=5) and (Task = 201) ] ] and *[ EventData [ Data [ @Name='TaskName' ]='\Tasks\test' ] ] and *[ EventData [ Data [ @Name='ResultCode' ]='2' ] ] </Select> </Query> </QueryList>

    Read the article

  • Parallelism in .NET – Part 14, The Different Forms of Task

    - by Reed
    Before discussing Task creation and actual usage in concurrent environments, I will briefly expand upon my introduction of the Task class and provide a short explanation of the distinct forms of Task.  The Task Parallel Library includes four distinct, though related, variations on the Task class. In my introduction to the Task class, I focused on the most basic version of Task.  This version of Task, the standard Task class, is most often used with an Action delegate.  This allows you to implement for each task within the task decomposition as a single delegate. Typically, when using the new threading constructs in .NET 4 and the Task Parallel Library, we use lambda expressions to define anonymous methods.  The advantage of using a lambda expression is that it allows the Action delegate to directly use variables in the calling scope.  This eliminates the need to make separate Task classes for Action<T>, Action<T1,T2>, and all of the other Action<…> delegate types.  As an example, suppose we wanted to make a Task to handle the ”Show Splash” task from our earlier decomposition.  Even if this task required parameters, such as a message to display, we could still use an Action delegate specified via a lambda: // Store this as a local variable string messageForSplashScreen = GetSplashScreenMessage(); // Create our task Task showSplashTask = new Task( () => { // We can use variables in our outer scope, // as well as methods scoped to our class! this.DisplaySplashScreen(messageForSplashScreen); }); .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; } This provides a huge amount of flexibility.  We can use this single form of task for any task which performs an operation, provided the only information we need to track is whether the task has completed successfully or not.  This leads to my first observation: Use a Task with a System.Action delegate for any task for which no result is generated. This observation leads to an obvious corollary: we also need a way to define a task which generates a result.  The Task Parallel Library provides this via the Task<TResult> class. Task<TResult> subclasses the standard Task class, providing one additional feature – the ability to return a value back to the user of the task.  This is done by switching from providing an Action delegate to providing a Func<TResult> delegate.  If we decompose our problem, and we realize we have one task where its result is required by a future operation, this can be handled via Task<TResult>.  For example, suppose we want to make a task for our “Check for Update” task, we could do: Task<bool> checkForUpdateTask = new Task<bool>( () => { return this.CheckWebsiteForUpdate(); }); Later, we would start this task, and perform some other work.  At any point in the future, we could get the value from the Task<TResult>.Result property, which will cause our thread to block until the task has finished processing: // This uses Task<bool> checkForUpdateTask generated above... // Start the task, typically on a background thread checkForUpdateTask.Start(); // Do some other work on our current thread this.DoSomeWork(); // Discover, from our background task, whether an update is available // This will block until our task completes bool updateAvailable = checkForUpdateTask.Result; This leads me to my second observation: Use a Task<TResult> with a System.Func<TResult> delegate for any task which generates a result. Task and Task<TResult> provide a much cleaner alternative to the previous Asynchronous Programming design patterns in the .NET framework.  Instead of trying to implement IAsyncResult, and providing BeginXXX() and EndXXX() methods, implementing an asynchronous programming API can be as simple as creating a method that returns a Task or Task<TResult>.  The client side of the pattern also is dramatically simplified – the client can call a method, then either choose to call task.Wait() or use task.Result when it needs to wait for the operation’s completion. While this provides a much cleaner model for future APIs, there is quite a bit of infrastructure built around the current Asynchronous Programming design patterns.  In order to provide a model to work with existing APIs, two other forms of Task exist.  There is a constructor for Task which takes an Action<Object> and a state parameter.  In addition, there is a constructor for creating a Task<TResult> which takes a Func<Object, TResult> as well as a state parameter.  When using these constructors, the state parameter is stored in the Task.AsyncState property. While these two overloads exist, and are usable directly, I strongly recommend avoiding this for new development.  The two forms of Task which take an object state parameter exist primarily for interoperability with traditional .NET Asynchronous Programming methodologies.  Using lambda expressions to capture variables from the scope of the creator is a much cleaner approach than using the untyped state parameters, since lambda expressions provide full type safety without introducing new variables.

    Read the article

  • Scheduled task does not run on WIndows 2003 server on VMWare unattened, runs fine otherwise

    - by lnm
    Scheduled task does not run on Windows 2003 server on VMWare. The same setup runs fine on standalone server. Test below explains the problem. We really need to run a more complex bat file, but this shows the issue. I have a bat file that copies a file from server A to server B. I use full path name, no drive mapping. Runs fine on server B from command prompt. I created a task that runs this bat file under a domain id with password that is part of administrator group on both servers. Task runs fine from Scheduled task screen, and as a scheduled task as long as somebody is logged into the server. If nobody is logged in, the task does not run. There is no error message in Task Scheduler log, just an entry that the task started, bit no entry for finish or an error code. To add insult to injury, if the task copies a file in the opposite direction, from server B to server A, it runs fine as a scheduled unattended task. If I copy a file from server B to server B, the task also runs fine unattended, I recreated exactly the same setup on a standalone server. No issues at all. I checked obvious things like the task has "run only as logged in" unchecked, domain id has run as a batch job privilege and logon rights, Task Scheduler service runs as a local system, automatic start. Any suggestions?

    Read the article

  • Modern programming language with intuitive concurrent programming abstractions

    - by faif
    I am interested in learning concurrent programming, focusing on the application/user level (not system programming). I am looking for a modern high level programming language that provides intuitive abstractions for writing concurrent applications. I want to focus on languages that increase productivity and hide the complexity of concurrent programming. To give some examples, I don't consider a good option writing multithreaded code in C, C++, or Java because IMHO my productivity is reduced and their programming model is not intuitive. On the other hand, languages that increase productivity and offer more intuitive abstractions such as Python and the multiprocessing module, Erlang, Clojure, Scala, etc. would be good options. What would you recommend based on your experience and why?

    Read the article

  • Advice on learning programming languages and math.

    - by Joris Ooms
    I feel like I'm getting stuck lately when it comes to learning about programming-related things; I thought I'd ask a question here and write it all down in the hope to get some pointers/advice from people. Perhaps writing it down helps me put things in perspective for myself aswell. I study Interactive Multimedia Design. This course is based on two things: graphic design on one hand, and web development on the other hand. I have quite a decent knowledge of web-related languages (the usual HTML/JS/PHP) and I'll be getting a course on ASP.NET next year. In my free time, I have learnt how to work with CodeIgniter, aswell as some diving into Ruby (and Rails) and basic iOS programming. In my first year of college I also did a class on Java (19/20 on the end result). This grade doesn't really mean anything though; I have the basics of OOP down but Java-wise, we learnt next to nothing. Considering the time I have been programming in, for example, PHP.. I can't say I'm bad at it. I'm definitely not good or great at it, but I'm decent. My teachers tell me I have the programming thing down. They just tell me I should keep on learning. So that's what I do, and I try to take in as much as possible; however, sometimes I'm unsure where to start and I have this tendency to always doubt myself. Now, for the 'question'. I want to get into iOS programming. I know iOS programming boils down to programming in Cocoa Touch and Objective-C. I also know Obj-C is a superset of C. I have done a class on C a couple of years ago, but I failed miserably. I got stuck at pointers and never really understood them.. Until like a month ago. I suddenly 'got' it. I have been working through a book on Objective-C for a week or so now, and I understand the basics (I'm at like.. chapter 6 or so). However, I keep running into similar problems as the ones I had when I did the C class: I suck at math. No, really. I come from a Latin-Modern Languages background in high school and I had nearly no math classes back then. I wanted to study Computer Science, but I failed there because of the miserable state of my mathematics knowledge. I can't explain why I'm suddenly talking about math here though, because it isn't directly related to programming.. yet it is. For example, the examples in the book I'm reading now are about programming a fraction-calculator. All good, I can do the programming when I get the formulas down.. but it takes me a full day or more to actually get to that point. I also find it hard to come up with ideas for myself. I made one small iOS app the other day and it's just a button / label kind of thing. When I press the button, it generates a random number. That's really all I could come up with. Can you 'learn' that? It probably comes down to creativity, but evidently, I'm not too great at being creative. Are there any sites or resources out there that provide something like a basic list of things you can program when you're just starting out? Maybe I'm focusing on too many things at once. I want to keep my HTML/CSS at a decent level, while learning PHP and CodeIgniter, while diving into Ruby on Rails and learning Objective-C and the iOS SDK at the same time. I just want to be good at something, I guess. The problem is that I can't seem to be happy with my PHP stuff. I want more, something 'harder'; that's why I decided to pick up the iOS thing. Like I said, I have the basics down of a lot of different languages. I can program something simple in Java, in C, in Objective-C as of this week.. but it ends there. Mostly because I can't come up with ideas for more complex applications, and also because I just doubt myself: 'Oh, that's too complex, I can never do that'. And then it ends there. To conclude my rant, let me basically rephrase my questions into a 'tl;dr' part. A. I want to get into iOS programming and I have basic knowledge of C/Objective-C. However, I struggle to come up with ideas of my own and implement them and I also suck at math which is something that isn't directly related to, yet often needed while programming. What can I do? B. I have an interest in a lot of different programming languages and I can't stop reading/learning. However, I don't feel like I'm good in anything. Should I perhaps focus on just one language for a year or longer, or keep taking it all in at the same time and hope I'll finally get them all down? C. Are there any resources out there that provide basic ideas of things I can program? I'm thinking about 'simple' command-line applications here to help me while studying C/Obj-C away from the whole iPhone SDK. Like I said, the examples in my book are mainly math-based (fraction calculator) and it's kinda hard. :( Thanks a lot for reading my post. I didn't plan it to be this long but oh well. Thanks in advance for any answers.

    Read the article

  • Introducing functional programming constructs in non-functional programming languages

    - by Giorgio
    This question has been going through my mind quite a lot lately and since I haven't found a convincing answer to it I would like to know if other users of this site have thought about it as well. In the recent years, even though OOP is still the most popular programming paradigm, functional programming is getting a lot of attention. I have only used OOP languages for my work (C++ and Java) but I am trying to learn some FP in my free time because I find it very interesting. So, I started learning Haskell three years ago and Scala last summer. I plan to learn some SML and Caml as well, and to brush up my (little) knowledge of Scheme. Well, a lot of plans (too ambitious?) but I hope I will find the time to learn at least the basics of FP during the next few years. What is important for me is how functional programming works and how / whether I can use it for some real projects. I have already developed small tools in Haskell. In spite of my strong interest for FP, I find it difficult to understand why functional programming constructs are being added to languages like C#, Java, C++, and so on. As a developer interested in FP, I find it more natural to use, say, Scala or Haskell, instead of waiting for the next FP feature to be added to my favourite non-FP language. In other words, why would I want to have only some FP in my originally non-FP language instead of looking for a language that has a better support for FP? For example, why should I be interested to have lambdas in Java if I can switch to Scala where I have much more FP concepts and access all the Java libraries anyway? Similarly: why do some FP in C# instead of using F# (to my knowledge, C# and F# can work together)? Java was designed to be OO. Fine. I can do OOP in Java (and I would like to keep using Java in that way). Scala was designed to support OOP + FP. Fine: I can use a mix of OOP and FP in Scala. Haskell was designed for FP: I can do FP in Haskell. If I need to tune the performance of a particular module, I can interface Haskell with some external routines in C. But why would I want to do OOP with just some basic FP in Java? So, my main point is: why are non-functional programming languages being extended with some functional concept? Shouldn't it be more comfortable (interesting, exciting, productive) to program in a language that has been designed from the very beginning to be functional or multi-paradigm? Don't different programming paradigms integrate better in a language that was designed for it than in a language in which one paradigm was only added later? The first explanation I could think of is that, since FP is a new concept (it isn't new at all, but it is new for many developers), it needs to be introduced gradually. However, I remember my switch from imperative to OOP: when I started to program in C++ (coming from Pascal and C) I really had to rethink the way in which I was coding, and to do it pretty fast. It was not gradual. So, this does not seem to be a good explanation to me. Or can it be that many non-FP programmers are not really interested in understanding and using functional programming, but they find it practically convenient to adopt certain FP-idioms in their non-FP language? IMPORTANT NOTE Just in case (because I have seen several language wars on this site): I mentioned the languages I know better, this question is in no way meant to start comparisons between different programming languages to decide which is better / worse. Also, I am not interested in a comparison of OOP versus FP (pros and cons). The point I am interested in is to understand why FP is being introduced one bit at a time into existing languages that were not designed for it even though there exist languages that were / are specifically designed to support FP.

    Read the article

  • Functional programming constructs in non-functional programming languages

    - by Giorgio
    This question has been going through my mind quite a lot lately and since I haven't found a convincing answer to it I would like to know if other users of this site have thought about it as well. In the recent years, even though OOP is still the most popular programming paradigm, functional programming is getting a lot of attention. I have only used OOP languages for my work (C++ and Java) but I am trying to learn some FP in my free time because I find it very interesting. So, I started learning Haskell three years ago and Scala last summer. I plan to learn some SML and Caml as well, and to brush up my (little) knowledge of Scheme. Well, a lot of plans (too ambitious?) but I hope I will find the time to learn at least the basics of FP during the next few years. What is important for me is how functional programming works and how / whether I can use it for some real projects. I have already developed small tools in Haskell. In spite of my strong interest for FP, I find it difficult to understand why functional programming constructs are being added to languages like C#, Java, C++, and so on. As a developer interested in FP, I find it more natural to use, say, Scala or Haskell, instead of waiting for the next FP feature to be added to my favourite non-FP language. In other words, why would I want to have only some FP in my originally non-FP language instead of looking for a language that has a better support for FP? For example, why should I be interested to have lambdas in Java if I can switch to Scala where I have much more FP concepts and access all the Java libraries anyway? Similarly: why do some FP in C# instead of using F# (to my knowledge, C# and F# can work together)? Java was designed to be OO. Fine. I can do OOP in Java (and I would like to keep using Java in that way). Scala was designed to support OOP + FP. Fine: I can use a mix of OOP and FP in Scala. Haskell was designed for FP: I can do FP in Haskell. If I need to tune the performance of a particular module, I can interface Haskell with some external routines in C. But why would I want to do OOP with just some basic FP in Java? So, my main point is: why are non-functional programming languages being extended with some functional concept? Shouldn't it be more comfortable (interesting, exciting, productive) to program in a language that has been designed from the very beginning to be functional or multi-paradigm? Don't different programming paradigms integrate better in a language that was designed for it than in a language in which one paradigm was only added later? The first explanation I could think of is that, since FP is a new concept (it isn't new at all, but it is new for many developers), it needs to be introduced gradually. However, I remember my switch from imperative to OOP: when I started to program in C++ (coming from Pascal and C) I really had to rethink the way in which I was coding, and to do it pretty fast. It was not gradual. So, this does not seem to be a good explanation to me. Also, I asked myself if my impression is just plainly wrong due to lack of knowledge. E.g., do C# and C++11 support FP as extensively as, say, Scala or Caml do? In this case, my question would be simply non-existent. Or can it be that many non-FP programmers are not really interested in using functional programming, but they find it practically convenient to adopt certain FP-idioms in their non-FP language? IMPORTANT NOTE Just in case (because I have seen several language wars on this site): I mentioned the languages I know better, this question is in no way meant to start comparisons between different programming languages to decide which is better / worse. Also, I am not interested in a comparison of OOP versus FP (pros and cons). The point I am interested in is to understand why FP is being introduced one bit at a time into existing languages that were not designed for it even though there exist languages that were / are specifically designed to support FP.

    Read the article

  • Modular programming is the method of programming small task or programs

    Modular programming is the method of programming small task or sub-programs that can be arranged in multiple variations to perform desired results. This methodology is great for preventing errors due to the fact that each task executes a specific process and can be debugged individually or within a larger program when combined with other tasks or sub programs. C# is a great example of how to implement modular programming because it allows for functions, methods, classes and objects to be use to create smaller sub programs. A program can be built from smaller pieces of code which saves development time and reduces the chance of errors because it is easier to test a small class or function for a simple solutions compared to testing a full program which has layers and layers of small programs working together.Yes, it is possible to write the same program using modular and non modular programming, but it is not recommend it. When you deal with non modular programs, they tend to contain a lot of spaghetti code which can be a pain to develop and not to mention debug especially if you did not write the code. In addition, in my experience they seem to have a lot more hidden bugs which waste debugging and development time. Modular programming methodology in comparision to non-mondular should be used when ever possible due to the use of small components. These small components allow business logic to be reused and is easier to maintain. From the user’s view point, they cannot really tell if the code is modular or not with today’s computers.

    Read the article

  • Parallelism in .NET – Part 13, Introducing the Task class

    - by Reed
    Once we’ve used a task-based decomposition to decompose a problem, we need a clean abstraction usable to implement the resulting decomposition.  Given that task decomposition is founded upon defining discrete tasks, .NET 4 has introduced a new API for dealing with task related issues, the aptly named Task class. The Task class is a wrapper for a delegate representing a single, discrete task within your decomposition.  We will go into various methods of construction for tasks later, but, when reduced to its fundamentals, an instance of a Task is nothing more than a wrapper around a delegate with some utility functionality added.  In order to fully understand the Task class within the new Task Parallel Library, it is important to realize that a task really is just a delegate – nothing more.  In particular, note that I never mentioned threading or parallelism in my description of a Task.  Although the Task class exists in the new System.Threading.Tasks namespace: Tasks are not directly related to threads or multithreading. Of course, Task instances will typically be used in our implementation of concurrency within an application, but the Task class itself does not provide the concurrency used.  The Task API supports using Tasks in an entirely single threaded, synchronous manner. Tasks are very much like standard delegates.  You can execute a task synchronously via Task.RunSynchronously(), or you can use Task.Start() to schedule a task to run, typically asynchronously.  This is very similar to using delegate.Invoke to execute a delegate synchronously, or using delegate.BeginInvoke to execute it asynchronously. The Task class adds some nice functionality on top of a standard delegate which improves usability in both synchronous and multithreaded environments. The first addition provided by Task is a means of handling cancellation via the new unified cancellation mechanism of .NET 4.  If the wrapped delegate within a Task raises an OperationCanceledException during it’s operation, which is typically generated via calling ThrowIfCancellationRequested on a CancellationToken, or if the CancellationToken used to construct a Task instance is flagged as canceled, the Task’s IsCanceled property will be set to true automatically.  This provides a clean way to determine whether a Task has been canceled, often without requiring specific exception handling. Tasks also provide a clean API which can be used for waiting on a task.  Although the Task class explicitly implements IAsyncResult, Tasks provide a nicer usage model than the traditional .NET Asynchronous Programming Model.  Instead of needing to track an IAsyncResult handle, you can just directly call Task.Wait() to block until a Task has completed.  Overloads exist for providing a timeout, a CancellationToken, or both to prevent waiting indefinitely.  In addition, the Task class provides static methods for waiting on multiple tasks – Task.WaitAll and Task.WaitAny, again with overloads providing time out options.  This provides a very simple, clean API for waiting on single or multiple tasks. Finally, Tasks provide a much nicer model for Exception handling.  If the delegate wrapped within a Task raises an exception, the exception will automatically get wrapped into an AggregateException and exposed via the Task.Exception property.  This exception is stored with the Task directly, and does not tear down the application.  Later, when Task.Wait() (or Task.WaitAll or Task.WaitAny) is called on this task, an AggregateException will be raised at that point if any of the tasks raised an exception.  For example, suppose we have the following code: Task taskOne = new Task( () => { throw new ApplicationException("Random Exception!"); }); Task taskTwo = new Task( () => { throw new ArgumentException("Different exception here"); }); // Start the tasks taskOne.Start(); taskTwo.Start(); try { Task.WaitAll(new[] { taskOne, taskTwo }); } catch (AggregateException e) { Console.WriteLine(e.InnerExceptions.Count); foreach (var inner in e.InnerExceptions) Console.WriteLine(inner.Message); } .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; } Here, our routine will print: 2 Different exception here Random Exception! Note that we had two separate tasks, each of which raised two distinctly different types of exceptions.  We can handle this cleanly, with very little code, in a much nicer manner than the Asynchronous Programming API.  We no longer need to handle TargetInvocationException or worry about implementing the Event-based Asynchronous Pattern properly by setting the AsyncCompletedEventArgs.Error property.  Instead, we just raise our exception as normal, and handle AggregateException in a single location in our calling code.

    Read the article

  • Difference between extensible programming and extendible programming?

    - by loudandclear
    What exactly is the different between "extensible programming" and "extendible programming?" Wikipedia states the following: The Lisp language community remained separate from the extensible language community, apparently because, as one researcher observed, any programming language in which programs and data are essentially interchangeable can be regarded as an extendible [sic] language. ... this can be seen very easily from the fact that Lisp has been used as an extendible language for years. If I'm understanding this correctly, it says "Lisp is extendible implies Lisp is not extensible". So what do these two terms mean, and how do they differ?

    Read the article

  • Task scheduler does not kill task

    - by Andomar
    We have a scheduled task that sometimes hangs. It just stops responding. On Windows 2003, we had task scheduler configured to kill the task after 3 hours. It's a 32-bit process. On Windows 2008 R2, we've set "Stop the task if it runs longer than" and "If the running task does not end when requested, force it to stop". However, when the task hangs, it is never stopped, and stays in process explorer for days. Any clue why Windows Scheduler would not kill a process? (This post has a reproducible setup for this issue.)

    Read the article

  • Why (not) logic programming?

    - by Anto
    I have not yet heard about any uses of a logical programming language (such as Prolog) in the software industry, nor do I know of usage of it in hobby programming or open source projects. It (Prolog) is used as an academic language to some extent, though (why is it used in academia?). This makes me wonder, why should you use logic programming, and why not? Why is it not getting any detectable industry usage?

    Read the article

  • How to make the transition to functional programming?

    - by tahatmat
    Lately, I have been very intrigued with F# which I have been working a bit with. Coming mostly from Java and C#, I like how concise and easily understandable it is. However, I believe that my background with these imperative languages disturb my way of thinking when programming in F#. I found a comparison of the imperative and functional approach, and I surely do recognize the "imperative way" of programming, but I also find it difficult to define problems to fit well with the functional approach. So my question is: How do I best make the transition from object-oriented programming to functional programming? Can you provide some tips or perhaps provide some literature that can help one to think "in functions" in general?

    Read the article

  • The Execute SQL Task

    In this article we are going to take you through the Execute SQL Task in SQL Server Integration Services for SQL Server 2005 (although it appies just as well to SQL Server 2008).  We will be covering all the essentials that you will need to know to effectively use this task and make it as flexible as possible. The things we will be looking at are as follows: A tour of the Task. The properties of the Task. After looking at these introductory topics we will then get into some examples. The examples will show different types of usage for the task: Returning a single value from a SQL query with two input parameters. Returning a rowset from a SQL query. Executing a stored procedure and retrieveing a rowset, a return value, an output parameter value and passing in an input parameter. Passing in the SQL Statement from a variable. Passing in the SQL Statement from a file. Tour Of The Task Before we can start to use the Execute SQL Task in our packages we are going to need to locate it in the toolbox. Let's do that now. Whilst in the Control Flow section of the package expand your toolbox and locate the Execute SQL Task. Below is how we found ours. Now drag the task onto the designer. As you can see from the following image we have a validation error appear telling us that no connection manager has been assigned to the task. This can be easily remedied by creating a connection manager. There are certain types of connection manager that are compatable with this task so we cannot just create any connection manager and these are detailed in a few graphics time. Double click on the task itself to take a look at the custom user interface provided to us for this task. The task will open on the general tab as shown below. Take a bit of time to have a look around here as throughout this article we will be revisting this page many times. Whilst on the general tab, drop down the combobox next to the ConnectionType property. In here you will see the types of connection manager which this task will accept. As with SQL Server 2000 DTS, SSIS allows you to output values from this task in a number of formats. Have a look at the combobox next to the Resultset property. The major difference here is the ability to output into XML. If you drop down the combobox next to the SQLSourceType property you will see the ways in which you can pass a SQL Statement into the task itself. We will have examples of each of these later on but certainly when we saw these for the first time we were very excited. Next to the SQLStatement property if you click in the empty box next to it you will see ellipses appear. Click on them and you will see the very basic query editor that becomes available to you. Alternatively after you have specified a connection manager for the task you can click on the Build Query button to bring up a completely different query editor. This is slightly inconsistent. Once you've finished looking around the general tab, move on to the next tab which is the parameter mapping tab. We shall, again, be visiting this tab throughout the article but to give you an initial heads up this is where you define the input, output and return values from your task. Note this is not where you specify the resultset. If however you now move on to the ResultSet tab this is where you define what variable will receive the output from your SQL Statement in whatever form that is. Property Expressions are one of the most amazing things to happen in SSIS and they will not be covered here as they deserve a whole article to themselves. Watch out for this as their usefulness will astound you. For a more detailed discussion of what should be the parameter markers in the SQL Statements on the General tab and how to map them to variables on the Parameter Mapping tab see Working with Parameters and Return Codes in the Execute SQL Task. Task Properties There are two places where you can specify the properties for your task. One is in the task UI itself and the other is in the property pane which will appear if you right click on your task and select Properties from the context menu. We will be doing plenty of property setting in the UI later so let's take a moment to have a look at the property pane. Below is a graphic showing our properties pane. Now we shall take you through all the properties and tell you exactly what they mean. A lot of these properties you will see across all tasks as well as the package because of everything's base structure The Container. BypassPrepare Should the statement be prepared before sending to the connection manager destination (True/False) Connection This is simply the name of the connection manager that the task will use. We can get this from the connection manager tray at the bottom of the package. DelayValidation Really interesting property and it tells the task to not validate until it actually executes. A usage for this may be that you are operating on table yet to be created but at runtime you know the table will be there. Description Very simply the description of your Task. Disable Should the task be enabled or not? You can also set this through a context menu by right clicking on the task itself. DisableEventHandlers As a result of events that happen in the task, should the event handlers for the container fire? ExecValueVariable The variable assigned here will get or set the execution value of the task. Expressions Expressions as we mentioned earlier are a really powerful tool in SSIS and this graphic below shows us a small peek of what you can do. We select a property on the left and assign an expression to the value of that property on the right causing the value to be dynamically changed at runtime. One of the most obvious uses of this is that the property value can be built dynamically from within the package allowing you a great deal of flexibility FailPackageOnFailure If this task fails does the package? FailParentOnFailure If this task fails does the parent container? A task can he hosted inside another container i.e. the For Each Loop Container and this would then be the parent. ForcedExecutionValue This property allows you to hard code an execution value for the task. ForcedExecutionValueType What is the datatype of the ForcedExecutionValue? ForceExecutionResult Force the task to return a certain execution result. This could then be used by the workflow constraints. Possible values are None, Success, Failure and Completion. ForceExecutionValue Should we force the execution result? IsolationLevel This is the transaction isolation level of the task. IsStoredProcedure Certain optimisations are made by the task if it knows that the query is a Stored Procedure invocation. The docs say this will always be false unless the connection is an ADO connection. LocaleID Gets or sets the LocaleID of the container. LoggingMode Should we log for this container and what settings should we use? The value choices are UseParentSetting, Enabled and Disabled. MaximumErrorCount How many times can the task fail before we call it a day? Name Very simply the name of the task. ResultSetType How do you want the results of your query returned? The choices are ResultSetType_None, ResultSetType_SingleRow, ResultSetType_Rowset and ResultSetType_XML. SqlStatementSource Your Query/SQL Statement. SqlStatementSourceType The method of specifying the query. Your choices here are DirectInput, FileConnection and Variables TimeOut How long should the task wait to receive results? TransactionOption How should the task handle being asked to join a transaction? Usage Examples As we move through the examples we will only cover in them what we think you must know and what we think you should see. This means that some of the more elementary steps like setting up variables will be covered in the early examples but skipped and simply referred to in later ones. All these examples used the AventureWorks database that comes with SQL Server 2005. Returning a Single Value, Passing in Two Input Parameters So the first thing we are going to do is add some variables to our package. The graphic below shows us those variables having been defined. Here the CountOfEmployees variable will be used as the output from the query and EndDate and StartDate will be used as input parameters. As you can see all these variables have been scoped to the package. Scoping allows us to have domains for variables. Each container has a scope and remember a package is a container as well. Variable values of the parent container can be seen in child containers but cannot be passed back up to the parent from a child. Our following graphic has had a number of changes made. The first of those changes is that we have created and assigned an OLEDB connection manager to this Task ExecuteSQL Task Connection. The next thing is we have made sure that the SQLSourceType property is set to Direct Input as we will be writing in our statement ourselves. We have also specified that only a single row will be returned from this query. The expressions we typed in was: SELECT COUNT(*) AS CountOfEmployees FROM HumanResources.Employee WHERE (HireDate BETWEEN ? AND ?) Moving on now to the Parameter Mapping tab this is where we are going to tell the task about our input paramaters. We Add them to the window specifying their direction and datatype. A quick word here about the structure of the variable name. As you can see SSIS has preceeded the variable with the word user. This is a default namespace for variables but you can create your own. When defining your variables if you look at the variables window title bar you will see some icons. If you hover over the last one on the right you will see it says "Choose Variable Columns". If you click the button you will see a list of checkbox options and one of them is namespace. after checking this you will see now where you can define your own namespace. The next tab, result set, is where we need to get back the value(s) returned from our statement and assign to a variable which in our case is CountOfEmployees so we can use it later perhaps. Because we are only returning a single value then if you remember from earlier we are allowed to assign a name to the resultset but it must be the name of the column (or alias) from the query. A really cool feature of Business Intelligence Studio being hosted by Visual Studio is that we get breakpoint support for free. In our package we set a Breakpoint so we can break the package and have a look in a watch window at the variable values as they appear to our task and what the variable value of our resultset is after the task has done the assignment. Here's that window now. As you can see the count of employess that matched the data range was 2. Returning a Rowset In this example we are going to return a resultset back to a variable after the task has executed not just a single row single value. There are no input parameters required so the variables window is nice and straight forward. One variable of type object. Here is the statement that will form the soure for our Resultset. select p.ProductNumber, p.name, pc.Name as ProductCategoryNameFROM Production.ProductCategory pcJOIN Production.ProductSubCategory pscON pc.ProductCategoryID = psc.ProductCategoryIDJOIN Production.Product pON psc.ProductSubCategoryID = p.ProductSubCategoryID We need to make sure that we have selected Full result set as the ResultSet as shown below on the task's General tab. Because there are no input parameters we can skip the parameter mapping tab and move straight to the Result Set tab. Here we need to Add our variable defined earlier and map it to the result name of 0 (remember we covered this earlier) Once we run the task we can again set a breakpoint and have a look at the values coming back from the task. In the following graphic you can see the result set returned to us as a COM object. We can do some pretty interesting things with this COM object and in later articles that is exactly what we shall be doing. Return Values, Input/Output Parameters and Returning a Rowset from a Stored Procedure This example is pretty much going to give us a taste of everything. We have already covered in the previous example how to specify the ResultSet to be a Full result set so we will not cover it again here. For this example we are going to need 4 variables. One for the return value, one for the input parameter, one for the output parameter and one for the result set. Here is the statement we want to execute. Note how much cleaner it is than if you wanted to do it using the current version of DTS. In the Parameter Mapping tab we are going to Add our variables and specify their direction and datatypes. In the Result Set tab we can now map our final variable to the rowset returned from the stored procedure. It really is as simple as that and we were amazed at how much easier it is than in DTS 2000. Passing in the SQL Statement from a Variable SSIS as we have mentioned is hugely more flexible than its predecessor and one of the things you will notice when moving around the tasks and the adapters is that a lot of them accept a variable as an input for something they need. The ExecuteSQL task is no different. It will allow us to pass in a string variable as the SQL Statement. This variable value could have been set earlier on from inside the package or it could have been populated from outside using a configuration. The ResultSet property is set to single row and we'll show you why in a second when we look at the variables. Note also the SQLSourceType property. Here's the General Tab again. Looking at the variable we have in this package you can see we have only two. One for the return value from the statement and one which is obviously for the statement itself. Again we need to map the Result name to our variable and this can be a named Result Name (The column name or alias returned by the query) and not 0. The expected result into our variable should be the amount of rows in the Person.Contact table and if we look in the watch window we see that it is.   Passing in the SQL Statement from a File The final example we are going to show is a really interesting one. We are going to pass in the SQL statement to the task by using a file connection manager. The file itself contains the statement to run. The first thing we are going to need to do is create our file connection mananger to point to our file. Click in the connections tray at the bottom of the designer, right click and choose "New File Connection" As you can see in the graphic below we have chosen to use an existing file and have passed in the name as well. Have a look around at the other "Usage Type" values available whilst you are here. Having set that up we can now see in the connection manager tray our file connection manager sitting alongside our OLE-DB connection we have been using for the rest of these examples. Now we can go back to the familiar General Tab to set up how the task will accept our file connection as the source. All the other properties in this task are set up exactly as we have been doing for other examples depending on the options chosen so we will not cover them again here.   We hope you will agree that the Execute SQL Task has changed considerably in this release from its DTS predecessor. It has a lot of options available but once you have configured it a few times you get to learn what needs to go where. We hope you have found this article useful.

    Read the article

  • Programming Pearls (2nd Edition) vs More Programming Pearls: Confessions of a Coder [closed]

    - by Geek
    I have been reading very good reviews of the books by Jon Bentley : Programming Pearls (2nd Edition) More Programming Pearls: Confessions of a Coder. I know that these books have been out there for a long time and I feel bad that I haven't read either one . But it is always better late than never . I understand that the second one was written after the first one . So are these two books complementary to each other ? Do the second one assume that the reader has read the first one ? For some one who haven't read either which one would you propose to read up first ?

    Read the article

  • Should "closed as duplicate" software programming be extreme or functional? [migrated]

    - by Web Developer
    I'm a web developer loving this site for it's potential, and it's Coffee look . I was reading a great question, that is this: click here and noticed 8 moderators tagged it as DUPLICATED! The question was closed! Obviously it isn't and I'm going to explain why if needed but it can be seen: the question is unique, is the case/story of a young who have SPECIFIC experience with C++ , VB and Assembler and asking, knowing this specifications an answer (It is not a general question like "hey I'm young can I do the programmer??") Let me know your opinion! do you think this question should or should not be closed? And let's think about also the people not only the "data" and "cases covered" ... do you think this is important too? or is better to keep a place where people doesn't count?

    Read the article

  • Windows Task Scheduler does not start task at next run time

    - by Dan C
    I have a Windows Server 2008 SP 2 Task Scheduler task that should run every 10 minutes. The trigger says "At 6:50 PM every day - After triggered, repeat every 10 minutes for a duration of 1 day." Looking at the Next Run Time, it says 6/18/2012 8:00 PM. However, when I let that time pass, the Next Run Time just changes to 8:10 PM but the task has not started and the Last Run Time is unchanged from yesterday. How can I get this task to run every 10 minutes when enabled no matter what. Similarly, I have other tasks that need to run on slightly different schedules: Every 30 minutes (5:30, 6:00, 6:30, etc) Every 30 minutes (5:35, 6:05, 6:35, etc) How can I define these intervals? And why does the task not start at the indicated Next Run Time?

    Read the article

1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >