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  • SQL SERVER – Get Schema Name from Object ID using OBJECT_SCHEMA_NAME

    - by pinaldave
    Sometime a simple solution have even simpler solutions but we often do not practice it as we do not see value in it or find it useful. Well, today’s blog post is also about something which I have seen not practiced much in codes. We are so much comfortable with alternative usage that we do not feel like switching how we query the data. I was going over forums and I noticed that at one place user has used following code to get Schema Name from ObjectID. USE AdventureWorks2012 GO SELECT s.name AS SchemaName, t.name AS TableName, s.schema_id, t.OBJECT_ID FROM sys.Tables t INNER JOIN sys.schemas s ON s.schema_id = t.schema_id WHERE t.name = OBJECT_NAME(46623209) GO Before I continue let me say I do not see anything wrong with this script. It is just fine and one of the way to get SchemaName from Object ID. However, I have been using function OBJECT_SCHEMA_NAME to get the schema name. If I have to write the same code from the beginning I would have written the same code as following. SELECT OBJECT_SCHEMA_NAME(46623209) AS SchemaName, t.name AS TableName, t.schema_id, t.OBJECT_ID FROM sys.tables t WHERE t.name = OBJECT_NAME(46623209) GO Now, both of the above code give you exact same result. If you remove the WHERE condition it will give you information of all the tables of the database. Now the question is which one is better – honestly – it is not about one is better than other. Use the one which you prefer to use. I prefer to use second one as it requires less typing. Let me ask you the same question to you – which method to get schema name do yo use? and Why? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology

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  • Does it make sense to write a build scripts in C++?

    - by Klaim
    I'm using CMake to generate my projects IDE/makefiles, but I still need to call custom "scripts" to manipulate my compiled files or even generate code. In previous projects I've been using Python and it was OK, but now I'm having serious trouble managing a lot of dependencies in two very big projects I'm working on so I want to minimize the dependencies everywhere. Someone suggested to me to use C++ to write my build scripts instead of adding a language dependency just for that. The projects themeselves already use C++ so there are several advantages that I can see: to build the whole project, only a C++ compiler and CMake would be necessary, nothing else (all the other dependencies are C or C++); C++ type safety (when using modern C++) makes everything easier to get "correct"; it's also the language I know the better so I'm more at ease with it even if I'm able to write some good Python code; potential gain in execution speed (but i don't think it will really be perceptible); However, I think there might be some drawbacks and I'm not sure of the real impact as I didn't try yet: might be longer to write the code (that said I'm not sure because I'm efficient enough in C++ to write something that work quickly, so maybe for this system it wouldn't be so long to write) (compilation time shouldn't be a problem for this case); I must assume that all the text files I'll read as input are in UTF-8, I'm not sure it can be easilly checked at runtime in C++ and the language will not check it for you; libraries in C++ are harder to manage than in scripting languages; I lack experience and forsight so maybe I'm missing advantages and drawbacks. So the question is: does it make sense to use C++ for this? do you have experiences to report and do you see advantages and disadvantages that might be important?

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  • How do I create my own programming language and a compiler for it

    - by Dave
    I am thorough with programming and have come across languages including BASIC, FORTRAN, COBOL, LISP, LOGO, Java, C++, C, MATLAB, Mathematica, Python, Ruby, Perl, JavaScript, Assembly and so on. I can't understand how people create programming languages and devise compilers for it. I also couldn't understand how people create OS like Windows, Mac, UNIX, DOS and so on. The other thing that is mysterious to me is how people create libraries like OpenGL, OpenCL, OpenCV, Cocoa, MFC and so on. The last thing I am unable to figure out is how scientists devise an assembly language and an assembler for a microprocessor. I would really like to learn all of these stuff and I am 15 years old. I always wanted to be a computer scientist someone like Babbage, Turing, Shannon, or Dennis Ritchie. I have already read Aho's Compiler Design and Tanenbaum's OS concepts book and they all only discuss concepts and code in a high level. They don't go into the details and nuances and how to devise a compiler or operating system. I want a concrete understanding so that I can create one myself and not just an understanding of what a thread, semaphore, process, or parsing is. I asked my brother about all this. He is a SB student in EECS at MIT and hasn't got a clue of how to actually create all these stuff in the real world. All he knows is just an understanding of Compiler Design and OS concepts like the ones that you guys have mentioned (i.e. like Thread, Synchronization, Concurrency, memory management, Lexical Analysis, Intermediate code generation and so on)

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  • virtual install from ISO not getting virtual kernel

    - by Pete
    I have a KVM host (12.04.5) that I have been installing guests on in variety of ways. I just noticed recently one of my guests was running a generic kernel when I'm fairly certain I specified minimum virtual machine during install from a 12.04.2 server iso. From what I understand it should be running a stripped down kernel "optimized" for VMs. I set up another server to test, this time using a 14.04.1, and sure enough I ended up with uname -r returning 3.13.0-32-generic. It seems that if I use an .iso to install, I end up with generic regardless. However building with the vmbuilder ... --flavour virtual --suite precise ... (I don't have trusty available yet) script gives me an ubuntu 12.04.5 LTS system running kernel 3.2.0-67-virtual. The server FAQ mentions I should be getting the virtual kernel. What are practical advantages of using linux-image-virtual kernel? gives me the impression that it doesn't really matter functionally (in my case I only have a couple VMs running). I first thought was maybe I was somehow not applying the correct options because the installer F4 menu doesn't really give great feedback if the mode has been selected or not. Looking in the log /var/log/installers/syslog I see Command line: file=/cdrom/preceed/ubuntu-server-minimalvm.seed ... I know that I can install the virtual kernel package down the road, but why am I not, or should I be getting the virtual flavor of kernel from an ISO install when doing an minimum VM install?

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  • How do I create my own programming language and a compiler for it

    - by Dave
    I am thorough with programming and have come across languages including BASIC, FORTRAN, COBOL, LISP, LOGO, Java, C++, C, MATLAB, Mathematica, Python, Ruby, Perl, Javascript, Assembly and so on. I can't understand how people create programming languages and devise compilers for it. I also couldn't understand how people create OS like Windows, Mac, UNIX, DOS and so on. The other thing that is mysterious to me is how people create libraries like OpenGL, OpenCL, OpenCV, Cocoa, MFC and so on. The last thing I am unable to figure out is how scientists devise an assembly language and an assembler for a microprocessor. I would really like to learn all of these stuff and I am 15 years old. I always wanted to be a computer scientist some one like Babbage, Turing, Shannon, or Dennis Ritchie. I have already read Aho's Compiler Design and Tanenbaum's OS concepts book and they all only discuss concepts and code in a high level. They don't go into the details and nuances and how to devise a compiler or operating system. I want a concrete understanding so that I can create one myself and not just an understanding of what a thread, semaphore, process, or parsing is. I asked my brother about all this. He is a SB student in EECS at MIT and hasn't got a clue of how to actually create all these stuff in the real world. All he knows is just an understanding of Compiler Design and OS concepts like the ones that you guys have mentioned (ie like Thread, Synchronisation, Concurrency, memory management, Lexical Analysis, Intermediate code generation and so on)

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  • Very large log files, what should I do?

    - by Masroor
    (This question deals with a similar issue, but it talks about a rotated log file.) Today I got a system message regarding very low /var space. As usual I executed the commands in the line of sudo apt-get clean which improved the scenario only slightly. Then I deleted the rotated log files which again provided very little improvement. Upon examination I find that some log files in the /var/log has grown up to be very huge ones. To be specific, ls -lSh /var/log gives, total 28G -rw-r----- 1 syslog adm 14G Aug 23 21:56 kern.log -rw-r----- 1 syslog adm 14G Aug 23 21:56 syslog -rw-rw-r-- 1 root utmp 390K Aug 23 21:47 wtmp -rw-r--r-- 1 root root 287K Aug 23 21:42 dpkg.log -rw-rw-r-- 1 root utmp 287K Aug 23 20:43 lastlog As we can see, the first two are the offending ones. I am mildly surprised why such large files have not been rotated. So, what should I do? Simply delete these files and then reboot? Or go for some more prudent steps? I am using Ubuntu 14.04.

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  • wrong kernel running after install

    - by ticktockhouse
    I have installed Ubuntu 14.04 from unetbootin. When it reboots after the install, uname -r says: 3.5.0-17-generic ..this means that no modules have loaded for the kernel that is actually installed (3.13.0-32-generic). Does anyone know why this kernel should be installed via the install process? Is it an artifact of using Unetbootin? Booting into the Unetbootin image gives the correct kernel, and thus the modules load. Knowing why is one thing, but I'm not sure how to remedy it now. Because no modules are loaded, I can't connect to the network or connect a USB drive. I've tried update-grub, which seems to find the correct kernel, but doesn't seem to tell the system to boot from it. I've also tried selecting the kernel at boot time using the "Advanced Options for Ubuntu", and the 3.13.x kernel is the only one listed. Selecting this lead to the 3.5.x kernel stubbornly loading.. I'm a fairly accomplished sysadmin, but this one has me flummoxed :) Can anyone help?

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  • Ask the Readers: How Do You Monitor Your Computer?

    - by Jason Fitzpatrick
    Beneath the shiny case of your computer and GUI of your operating system there’s a lot–CPU utilization, memory access, and disk space consumption to name a few things–you can keep an eye on. How do you keep an eye on resource utilization and more on your computer? Image available as wallpaper here. Whether you’re carefully managing a small pool of RAM, making sure your abundant apps don’t bog down your processor, or you just like having an intimate view of what’s going on in the guts of your computer, we want to hear all about the tools you use to do it. How and why do you monitor your computer? From disk use to case temps, any kind of monitoring is fair game. Sound off in the comments with the how and why of your monitoring arrangement and then be sure to stop back in on Friday for the What You Said roundup to see what tricks and tools your fellow readers are using to keep an eye on their hardware. HTG Explains: How Antivirus Software Works HTG Explains: Why Deleted Files Can Be Recovered and How You Can Prevent It HTG Explains: What Are the Sys Rq, Scroll Lock, and Pause/Break Keys on My Keyboard?

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  • What is the program "Additional Drivers" (jockey-gtk) talking me about?

    - by Robert Vila
    The program says: "No proprietary drivers are in use on this system" But it doesn't say if it is talking about graphical drivers only or what. Then, it lists two drivers: NVIDIA accelerated graphics driver (version 173). NVIDIA accelerated graphics driver (version current) [recomended] Both have exactly the same description. What is the difference then? When I select the 1st one, it says: "This river is not activated",and there's a button to "activate" it. When I select the 2nd one, it says: "This river is activated but it is not currently in use", and the button is to "remove". So which one is in use? Why or what for should I have activated (enabled) and not in use? If it is in use it is activated? What is the difference between activate and remove? and what is the relationship between installed, activated, in use, enabled and removed, disabled, inactive and not-installed? Why can I activate the inactivated and remove (but not deactivate) the activated that is not in use? All this is very puzzling... What other drivers can I use for an Apple MacBook pro 3,1 and how? I see that there's a nouveau and I heard that there was going to be a new open source even better. > -display > description: VGA compatible controller > product: G84 [GeForce 8600M GT] > vendor: nVidia Corporation

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  • Does it make sense to write build scripts in C++?

    - by Klaim
    I'm using CMake to generate my projects IDE/makefiles, but I still need to call custom "scripts" to manipulate my compiled files or even generate code. In previous projects I've been using Python and it was OK, but now I'm having serious trouble managing a lot of dependencies in two very big projects I'm working on so I want to minimize the dependencies everywhere. Someone suggested to me to use C++ to write my build scripts instead of adding a language dependency just for that. The projects themeselves already use C++ so there are several advantages that I can see: to build the whole project, only a C++ compiler and CMake would be necessary, nothing else (all the other dependencies are C or C++); C++ type safety (when using modern C++) makes everything easier to get "correct"; it's also the language I know the better so I'm more at ease with it even if I'm able to write some good Python code; potential gain in execution speed (but i don't think it will really be perceptible); However, I think there might be some drawbacks and I'm not sure of the real impact as I didn't try yet: might be longer to write the code (that said I'm not sure because I'm efficient enough in C++ to write something that work quickly, so maybe for this system it wouldn't be so long to write) (compilation time shouldn't be a problem for this case); I must assume that all the text files I'll read as input are in UTF-8, I'm not sure it can be easilly checked at runtime in C++ and the language will not check it for you; libraries in C++ are harder to manage than in scripting languages; I lack experience and forsight so maybe I'm missing advantages and drawbacks. So the question is: does it make sense to use C++ for this? do you have experiences to report and do you see advantages and disadvantages that might be important?

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  • not being able to access any sudo function on my pc

    - by explorex
    Hi, I am not being to access any functions in my desktop and I don't have an OS besides Ubuntu 10.04 Lucid Linux and I am new to ubuntu. I think I rebooted my computer thinking that Google Chrome crashed. I opened Google Chrome but it showed opening message but never opened so I restarted my computer. and when my system was loading ('i was playing with keyboard dont know what I typed') and when by ubutnu loaded, I was unable to access anything some of characteristics are listed below I cannot hear any sound I cannot access wired ethernet connection on the right corner where I usually enable to access interne and I have no internet. There is no local apache server either. when ever I try to start apacer I get setuid must be root or something. When I type sudo then I get message setuid must be root. I cannot access orther external storage devices like pendrive and portable hard drive and cannot mount my other drives with FAT32 filesystem. When I try to start my apache webserver with out typing sudo then I get message cannnot open socket or something like it. EDIT:: i remember also doing command chown -R www-data / earlier and got error message EDIT:: and i cannot shutdown my computer, it only logs off

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  • C# asp.net EF MVC postgresql error 23505: Duplicate key violates unique constraint

    - by user2721755
    EDIT: It was issue with database table - dropping and recreating table id column did the work. Problem solved. I'm trying to build web application, that is connected to postgresql database. Results are displaying in view with Kendo UI. When I'm trying to add new row (with Kendo UI 'Add new record' button), I get error 23505: 'Duplicate key violates unique constraint'. My guess is, that EF takes id to insert from the beginning, not the last one, because after 35 (it's number of rows in table) tries - and errors - adding works perfectly. Can someone help me to understand, what's wrong? Model: using System.ComponentModel.DataAnnotations; using System.ComponentModel.DataAnnotations.Schema; namespace MainConfigTest.Models { [Table("mainconfig", Schema = "public")] public class Mainconfig { [Column("id")] [Key] [Editable(false)] public int Id { get; set; } [Column("descr")] [Editable(true)] public string Descr { get; set; } [Column("hibversion")] [Required] [Editable(true)] public long Hibversion { get; set; } [Column("mckey")] [Required] [Editable(true)] public string Mckey { get; set; } [Column("valuexml")] [Editable(true)] public string Valuexml { get; set; } [Column("mcvalue")] [Editable(true)] public string Mcvalue { get; set; } } } Context: using System.Data.Entity; namespace MainConfigTest.Models { public class MainConfigContext : DbContext { public DbSet<Mainconfig> Mainconfig { get; set; } } } Controller: namespace MainConfigTest.Controllers { public class MainConfigController : Controller { #region Properties private Models.MainConfigContext db = new Models.MainConfigContext(); private string mainTitle = "Mainconfig (Kendo UI)"; #endregion #region Initialization public MainConfigController() { ViewBag.MainTitle = mainTitle; } #endregion #region Ajax [HttpGet] public JsonResult GetMainconfig() { int take = HttpContext.Request["take"] == null ? 5 : Convert.ToInt32(HttpContext.Request["take"]); int skip = HttpContext.Request["skip"] == null ? 0 : Convert.ToInt32(HttpContext.Request["skip"]); Array data = (from Models.Mainconfig c in db.Mainconfig select c).OrderBy(c => c.Id).ToArray().Skip(skip).Take(take).ToArray(); return Json(new Models.MainconfigResponse(data, db.Mainconfig.Count()), JsonRequestBehavior.AllowGet); } [HttpPost] public JsonResult Create() { try { Mainconfig itemToAdd = new Mainconfig() { Descr = Convert.ToString(HttpContext.Request["Descr"]), Hibversion = Convert.ToInt64(HttpContext.Request["Hibversion"]), Mckey = Convert.ToString(HttpContext.Request["Mckey"]), Valuexml = Convert.ToString(HttpContext.Request["Valuexml"]), Mcvalue = Convert.ToString(HttpContext.Request["Mcvalue"]) }; db.Mainconfig.Add(itemToAdd); db.SaveChanges(); return Json(new { Success = true }); } catch (InvalidOperationException ex) { return Json(new { Success = false, msg = ex }); } } //other methods } } Kendo UI script in view: <script type="text/javascript"> $(document).ready(function () { $("#config-grid").kendoGrid({ sortable: true, pageable: true, scrollable: false, toolbar: ["create"], editable: { mode: "popup" }, dataSource: { pageSize: 5, serverPaging: true, transport: { read: { url: '@Url.Action("GetMainconfig")', dataType: "json" }, update: { url: '@Url.Action("Update")', type: "Post", dataType: "json", complete: function (e) { $("#config-grid").data("kendoGrid").dataSource.read(); } }, destroy: { url: '@Url.Action("Delete")', type: "Post", dataType: "json" }, create: { url: '@Url.Action("Create")', type: "Post", dataType: "json", complete: function (e) { $("#config-grid").data("kendoGrid").dataSource.read(); } }, }, error: function (e) { if(e.Success == false) { this.cancelChanges(); } }, schema: { data: "Data", total: "Total", model: { id: "Id", fields: { Id: { editable: false, nullable: true }, Descr: { type: "string"}, Hibversion: { type: "number", validation: {required: true,}, }, Mckey: { type: "string", validation: { required: true, }, }, Valuexml:{ type: "string"}, Mcvalue: { type: "string" } } } } }, //end DataSource // generate columns etc. Mainconfig table structure: id serial NOT NULL, descr character varying(200), hibversion bigint NOT NULL, mckey character varying(100) NOT NULL, valuexml character varying(8000), mcvalue character varying(200), CONSTRAINT mainconfig_pkey PRIMARY KEY (id), CONSTRAINT mainconfig_mckey_key UNIQUE (mckey) Any help will be appreciated.

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  • Nhibernate fires SQL commands

    - by Chris
    Hi all, when updating an entity A, NHibernate also send an SQL update command for some other entity B. A and B are not related. Just before saving entity A, the parent of entity B is loaded via a SQLQuery. Then, when accessed, B is lazy loaded (part of a collection). If I save entity A an update statement for entity B is generated as well. How can that be, that when saving an entity, another entity loaded before but is not related to the entity saved, is updated as well?! Can I somehow track where the update comes from? Btw. I am using an save event listener. Could it be that this is always triggered for entity loaded, even though they are not saved explicitly? public class EntitySaveEventListener : NHibernate.Event.Default.DefaultSaveEventListener { protected override object PerformSaveOrUpdate(SaveOrUpdateEvent e) { //auditing return base.PerformSaveOrUpdate(e); } } Update (sorry for providing not enough info): I tracked it down a bit. A select stateement on a entity called address is executed (is it lazy loaded by a parent). Then I create a new entity called Request. Right before saving this entity a session flush is called which updates the address, even though I did not call save or update on the address. Address is a collection within Request. <class name="Request" table="Request"> <bag name="addresses" access="field" cascade="all-delete-orphan" where="IsDeleted = 0"> <key column="RequestId"/> <one-to-many class="Address"/> </bag> ... // address is fetched only NHibernate.SQL: 2010-02-17 11:47:21,306 [21] DEBUG NHibernate.SQL [(null)] - SELECT addresses0_.RequestId as ServiceP8_3_, .... // session flushed here // address is updated NHibernate.SQL: 2010-02-17 11:47:34,306 [21] DEBUG NHibernate.SQL [(null)] - Batch commands: command 0:UPDATE Address SET Street = @p0, ..... Would the address be updated automatically when it is manipulated somehow even though it is not explicitly saved via it's parent (cascade)?

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  • [Database] How to model this one-to-one relation?

    - by pbean
    I have several entities which respresent different types of users who need to be able to log in to a particular system. Additionally, they have different types of information associated with them. For example: a "general user", which has an e-mail address and "admin user", which has a workstation number (note that this a hypothetical case). Both entities also share common properties like first name, surname, address and telephone number. Finally, they naturally need to have a (unique) user name and a password to log in. In the application, the user just has to fill in his user name and password, and the functionality of the application changes slightly according to the type of the user. You can imagine that the username needs to be unique for this work. How should I model this effectively? I can't just create two tables, because then I can't force a unique constaint on the user name. I also can't put them all in just one table, because they have different types of specific information associated to them. I think I might need 3 seperate tables, one for "users" (with user name and password), one for the "general users" and another one for the "admin users", but how would the relations between these work? Or is there another solution? (By the way, the target DBMS is MySQL, so I don't think generalization is supported in the database system itself).

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  • Authentication Problem in Silverlight - Cannot connect to SQL Server

    - by Johann
    Hi All, At the moment, when I try to register a user using the default Business Template in Silverlight, I am getting an error. Basically I am following a tutorial found on Channel 9 on how to build a business app with Silverlight. "An error has occurred while establishing a connection to the server. (provider: Named Pipes Provider, error: 40 – Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 5) An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Named Pipes Provider, error: 40 – Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 1326)". I found a blog where it identifies the problem, and followed every step, however I am still getting the same problems. Here is my connection string:- <add name="SIEventManagerEntities" connectionString="metadata=res://*/EventManagerDBModel.csdl|res://*/EventManagerDBModel.ssdl|res://*/EventManagerDBModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=MONFU-PC;Initial Catalog=SIEventManager;Integrated Security=SSPI;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" /> Any help would really be very much appreciated! Thanks

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  • When should EntityManagerFactory instance be created/opened ?

    - by masato-san
    Ok, I read bunch of articles/examples how to write Entity Manager Factory in singleton. One of them easiest for me to understand a bit: http://javanotepad.blogspot.com/2007/05/jpa-entitymanagerfactory-in-web.html I learned that EntityManagerFactory (EMF) should only be created once preferably in application scope. And also make sure to close the EMF once it's used (?) So I wrote EMF helper class for business methods to use: public class EmProvider { private static final String DB_PU = "KogaAlphaPU"; public static final boolean DEBUG = true; private static final EmProvider singleton = new EmProvider(); private EntityManagerFactory emf; private EmProvider() {} public static EmProvider getInstance() { return singleton; } public EntityManagerFactory getEntityManagerFactory() { if(emf == null) { emf = Persistence.createEntityManagerFactory(DB_PU); } if(DEBUG) { System.out.println("factory created on: " + new Date()); } return emf; } public void closeEmf() { if(emf.isOpen() || emf != null) { emf.close(); } emf = null; if(DEBUG) { System.out.println("EMF closed at: " + new Date()); } } }//end class And my method using EmProvider: public String foo() { EntityManager em = null; List<Object[]> out = null; try { em = EmProvider.getInstance().getEntityManagerFactory().createEntityManager(); Query query = em.createNativeQuery(JPQL_JOIN); //just some random query out = query.getResultList(); } catch(Exception e) { //handle error.... } finally { if(em != null) { em.close(); //make sure to close EntityManager } } I made sure to close EntityManager (em) within method level as suggested. But when should EntityManagerFactory be closed then? And why EMF has to be singleton so bad??? I read about concurrency issues but as I am not experienced multi-thread-grammer, I can't really be clear on this idea.

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  • Searching For A Record After A LINQ query

    - by Justin
    I'm confused to why this is happening. I'm new to LINQ so I'm clearly missing something here, that is probably pretty easy. I've looked up help on the topic, but I don't really know what to ask so I haven't found any answers that really address my question. This doesn't work It throws an EntityCommandExecutionException when the FirstOrDefault method is executed. var query = from band in context.BandsEntitySet where band.ID == 12345 select band; string venueName = "Willis Park"; foreach (var item in query) { var venue = context.VenueEntitySet.FirstOrDefault(r => r.Venue.Equals(venueName)); } This works var query = from band in context.BandsEntitySet where band.ID == 12345 select band; var bandList = query.toList(); string venueName = "Willis Park"; foreach (var item in bandList) { var venue = context.VenueEntitySet.FirstOrDefault(r => r.Venue.Equals(venueName)); } My question is simple: Why is the exception being thrown? And why does creating a list from the query allow me to use the FirstOrDefault method? Exception Message: A first chance exception of type 'System.Data.EntityCommandExecutionException' occurred in System.Data.Entity.dll I guess I am wrong in my assumption that query is a list? Then what is it exactly? I'm confused because this doesn't throw an exception: foreach (var item in query) { var area = item.VenueArea; } I'd appreciate any help on this issue. thanks, Justin

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  • OrderBy Linq.Expression as parameter = (Of Func(Of T,IComparable)) to perform LinqToEntity is not working

    - by NicoJuicy
    I'd like to get this working: Call: (Count & Page are used for pagination, so Count = 20 and Page = 1 for example, for the first 20 values). Sorting should be by name LeverancierService.GetLeveranciers(Function(el) el.Name, Count, Page) Equivalent in c#: LeverancierService.GetLeveranciers(el= el.Name, Count, Page) Method that gives an error (parameters shown above): Public Overridable Function GetAllPaged(orderby As Expression(Of Func(Of T, IComparable)), ByVal Count As Integer, ByVal Page As Integer) As IEnumerable(Of T) Return dbset.OrderBy(orderby).Skip((Page - 1) * Count).Take(Count).ToList() End Function Already tried changing it to this, but it gives the same error: Public Overridable Function GetAllPaged(Of TOrderBy)(orderby As Expression(Of Func(Of T, TOrderBy)), ByVal Count As Integer, ByVal Page As Integer) As IEnumerable(Of T) Return dbset.OrderBy(orderby).Skip((Page - 1) * Count).Take(Count).ToList() End Function Error: Unable to cast the type 'System.String' to type 'System.IComparable'. LINQ to Entities only supports casting Entity Data Model primitive types. Any idea how to do this? Extra info: I'm in a DDD-layered application, so the parameter should stay the same as the called method is an overridden interface (eg. if i change this, i have to do this for 200 times or so, because it's in VB.Net and not in C# (= 1 change) ) I know there is a way to change the expression to a string and then use DLinq (= Dynamic Linq), but that's not how it should be.

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  • Shaping EF LINQ Query Results Using Multi-Table Includes

    - by sisdog
    I have a simple LINQ EF query below using the method syntax. I'm using my Include statement to join four tables: Event and Doc are the two main tables, EventDoc is a many-to-many link table, and DocUsage is a lookup table. My challenge is that I'd like to shape my results by only selecting specific columns from each of the four tables. But, the compiler is giving a compiler is giving me the following error: 'System.Data.Objects.DataClasses.EntityCollection does not contain a definition for "Doc' and no extension method 'Doc' accepting a first argument of type 'System.Data.Objects.DataClasses.EntityCollection' could be found. I'm sure this is something easy but I'm not figuring it out. I haven't been able to find an example of someone using the multi-table include but also shaping the projection. Thx,Mark var qry= context.Event .Include("EventDoc.Doc.DocUsage") .Select(n => new { n.EventDate, n.EventDoc.Doc.Filename, //<=COMPILER ERROR HERE n.EventDoc.Doc.DocUsage.Usage }) .ToList(); EventDoc ed; Doc d = ed.Doc; //<=NO COMPILER ERROR SO I KNOW MY MODEL'S CORRECT DocUsage du = d.DocUsage;

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  • LINQ EF not saving to database...

    - by Keith Barrows
    I guess this is a continuation of the last question I asked: http://stackoverflow.com/questions/2587542/bulk-insert-and-update-with-ado-net-entity-framework. I am not getting any errors while doing inserts yet no data is actually going into my DB. My DB is a SDF file (SQL CE). Any ideas what to check? My app.config looks like: <?xml version="1.0" encoding="utf-8"?> <configuration> <configSections> </configSections> <connectionStrings> <add name="Lab_Use_Billing.Properties.Settings.LabUseConnectionString" connectionString="Data Source=|DataDirectory|\Models\LabUse.sdf" providerName="Microsoft.SqlServerCe.Client.3.5" /> <add name="LabUseEntities" connectionString="metadata=res://*/Models.LabUseEntities.csdl|res://*/Models.LabUseEntities.ssdl|res://*/Models.LabUseEntities.msl; provider=System.Data.SqlServerCe.3.5; provider connection string=&quot;Data Source=|DataDirectory|\Models\LabUse.sdf&quot;" providerName="System.Data.EntityClient" /> </connectionStrings> </configuration> TIA

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  • EF 4.0 Guid or Int as A primary Key

    - by bigb
    I am Implementing custom ASPNetMembership using EF 4.0 Is there any reason why i should use Guid as a primary key in User tables? As far as i know Int as a PK on SQL Server more performanced than strings. And Int is easier to iterate. Also, for security purpose if i need to pass this it id somewhere in url i may encrypt it somehow and pass it like a strings with no probs. But if i want to use auto generated Guid on SQL Server side using EF 4.0 i need to do this trick http://leedumond.com/blog/using-a-guid-as-an-entitykey-in-entity-framework-4/ I can't see any cases why i should use Guid as PK, may be only one if system going to have millions ans millions users, but also, theoretically, Guid could be duplicated sometime isn't so? Anyway Int32 size is 2,147.483.647 it is pretty much even for very-very big system, but if this number is still not enough I may go with Int64, in that cases I may have 9,223.372.036.854.775.807 rows. Pretty much huh? From another hand, M$ using Guids as PK in their ASPNetMembership implementation. [aspnetdb].[aspnet_Users] - PK UserId Type uniqueidentifier, should be some reasons/explanation why the did it?! May be some one has any ideas/experience about that?

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  • WPF TextBlock refresh in real time

    - by TheOnlyBrien
    I'm new to C#, in fact, this is one of the first projects I've tried to start on my own. I am curious why the TextBlock will not refresh with the following code? The WPF window does not even show up when I add the "while" loop to the code. I just want this to have a real time display of the days since I was born. Please help me out or give me constructive direction. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; namespace daysAliveWPF { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); DateTime myBirthday = new DateTime(1984, 01, 19); while (true) { TimeSpan daysAlive = DateTime.Now.Subtract(myBirthday); MyTextBlock.Text = daysAlive.TotalDays.ToString(); } } } } Similar code has worked in a Console Window application, so I don't understand what's going on here. Console Application code snip that did work is: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace DisplayRealTime { class Program { static void Main(string[] args) { DateTime myBirthday = new DateTime(1984, 06, 19); while (true) { TimeSpan daysAlive = DateTime.Now.Subtract(myBirthday); Console.Write("\rTotal Days Alive: {0}", daysAlive.TotalDays.ToString(".#####")); } } } } Thank you!

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  • How does rc job work / order of (contradicting) "start on ..." and "stop on ..." stanzas

    - by Binarus
    Hi, I just can't understand how Upstart's rc job definition in Natty 11.04 works. To illustrate the problem, here is the definition (empty lines and comments are left out): start on runlevel [0123456] stop on runlevel [!$RUNLEVEL] export RUNLEVEL export PREVLEVEL console output env INIT_VERBOSE task exec /etc/init.d/rc $RUNLEVEL Let's suppose we currently are in runlevel 2 and the rc job is stopped (that is exactly the situation after booting my box and logging in via SSH). Now, let's assume that the system switches to runlevel 3, for example due to a command like "telinit 3" given by root. What will happen to the rc job? Obviously, the rc job will be started since it is currently stopped and the event runlevel 3 is matching the start events. But from now on, things are unclear to me: According to the manual $RUNLEVEL evaluates to the new runlevel when the job is started (that means 3 in our example). Therefore, the next stanza "stop on runlevel [!$RUNLEVEL]" translates to "stop on runlevel [!3]"; that means we have a first stanza which will trigger the job, but the second stanza will never stop the job and seems to be useless. Since I know that the Ubuntu / Upstart people won't do useless things, I must be heavily misunderstanding something. I would be grateful for any explanation. While trying to understand this, an additional question came to my mind. If I had contradicting start and stop triggers, for example start on foo stop on foo what would happen? I swear I never will do that, but I am nevertheless very interested in how Upstart handles that on the theoretical level. Thank you very much! Editing the question as a reaction on geekosaur's first answer: I can see the parallelism, but it is not that easy (at least, not to me). Let's assume the job aurrently is still running, and a new runlevel event comes in (of course, the new runlevel is different from the current one). Then, the following should happen: 1) The job is single instance. That means that "start on ..." won't be triggered since the job is currently running; $RUNLEVEL is not touched. 2) "stop on ..." will be triggered since the new runlevel is different from $RUNLEVEL, so the job will be aborted. 3) Now, the job is stopped and waiting. I can't see how it is restarted with the new runlevel. AFAIK, initctl emits events only once, so "start on ..." won't be triggered and the new runlevel won't be entered. I know that I still misunderstanding something, and I am grateful for explanations. Thank you very much!

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  • Upstart: How does rc job work / order of (contradicting) "start on ..." and "stop on ..." stanzas

    - by Binarus
    Hi, I just can't understand how Upstart's rc job definition in Natty 11.04 works. To illustrate the problem, here is the definition (empty lines and comments are left out): start on runlevel [0123456] stop on runlevel [!$RUNLEVEL] export RUNLEVEL export PREVLEVEL console output env INIT_VERBOSE task exec /etc/init.d/rc $RUNLEVEL Let's suppose we currently are in runlevel 2 and the rc job is stopped (that is exactly the situation after booting my box and logging in via SSH). Now, let's assume that the system switches to runlevel 3, for example due to a command like "telinit 3" given by root. What will happen to the rc job? Obviously, the rc job will be started since it is currently stopped and the event runlevel 3 is matching the start events. But from now on, things are unclear to me: According to the manual $RUNLEVEL evaluates to the new runlevel when the job is started (that means 3 in our example). Therefore, the next stanza "stop on runlevel [!$RUNLEVEL]" translates to "stop on runlevel [!3]"; that means we have a first stanza which will trigger the job, but the second stanza will never stop the job and seems to be useless. Since I know that the Ubuntu / Upstart people won't do useless things, I must be heavily misunderstanding something. I would be grateful for any explanation. While trying to understand this, an additional question came to my mind. If I had contradicting start and stop triggers, for example start on foo stop on foo what would happen? I swear I never will do that, but I am nevertheless very interested in how Upstart handles that on the theoretical level. Thank you very much! Editing the question as a reaction on geekosaur's first answer: I can see the parallelism, but it is not that easy (at least, not to me). Let's assume the job aurrently is still running, and a new runlevel event comes in (of course, the new runlevel is different from the current one). Then, the following should happen: 1) The job is single instance. That means that "start on ..." won't be triggered since the job is currently running; $RUNLEVEL is not touched. 2) "stop on ..." will be triggered since the new runlevel is different from $RUNLEVEL, so the job will be aborted. 3) Now, the job is stopped and waiting. I can't see how it is restarted with the new runlevel. AFAIK, initctl emits events only once, so "start on ..." won't be triggered and the new runlevel won't be entered. I know that I still misunderstanding something, and I am grateful for explanations. Thank you very much!

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  • What are some reasonable stylistic limits on type inference?

    - by Jon Purdy
    C++0x adds pretty darn comprehensive type inference support. I'm sorely tempted to use it everywhere possible to avoid undue repetition, but I'm wondering if removing explicit type information all over the place is such a good idea. Consider this rather contrived example: Foo.h: #include <set> class Foo { private: static std::set<Foo*> instances; public: Foo(); ~Foo(); // What does it return? Who cares! Just forward it! static decltype(instances.begin()) begin() { return instances.begin(); } static decltype(instances.end()) end() { return instances.end(); } }; Foo.cpp: #include <Foo.h> #include <Bar.h> // The type need only be specified in one location! // But I do have to open the header to find out what it actually is. decltype(Foo::instances) Foo::instances; Foo() { // What is the type of x? auto x = Bar::get_something(); // What does do_something() return? auto y = x.do_something(*this); // Well, it's convertible to bool somehow... if (!y) throw "a constant, old school"; instances.insert(this); } ~Foo() { instances.erase(this); } Would you say this is reasonable, or is it completely ridiculous? After all, especially if you're used to developing in a dynamic language, you don't really need to care all that much about the types of things, and can trust that the compiler will catch any egregious abuses of the type system. But for those of you that rely on editor support for method signatures, you're out of luck, so using this style in a library interface is probably really bad practice. I find that writing things with all possible types implicit actually makes my code a lot easier for me to follow, because it removes nearly all of the usual clutter of C++. Your mileage may, of course, vary, and that's what I'm interested in hearing about. What are the specific advantages and disadvantages to radical use of type inference?

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