News, examples, tips, ideas and plans.
Thoughts around ORM, .NET and SQL databases.

Thursday, February 15, 2018

DataObjects.Net 5.0.17 Beta 3

We have released a new version of DataObjects.Net

In the version following changes were performed:

[main] Fixed certain scenarios when In() or Contains() operations in query led to  NullReferenceExecption exception
[main] Persist operation no longer breaks enumeration of EntitySet items.

Detailed explanation of these changes is in the post.

As usual you can get it from our website or install from Nuget library.


NullReferenceException during query translation

Sometimes inclusion of a static fields in operations like In() or Contains() resulted in the exception. Instance fields are handled correctly though. For example,

   [TestFixture]
  public class ContainsTest
  {
    // ...
    // some other members 
    // ...

    private static int StaticItemId = 1;
    private int InstanceItemId = 1;

    [Test]
    public void MainTest()
    {
      using (var domain = Domain.Build(GetDomainConfiguration())
      using (var session = domain.OpenSession())
      using (var trasnaction = session.OpenTransaction()) {
        var ids = new[] {1, 2};
        // works fine
        var count = session.Query.All<TestEntity>()
          .Count(e => ids.Contains(InstanceItemId)));

        // used to be a problem
        var count = session.Query.All<TestEntity>()
          .Count(e => ids.Contains(StaticItemId)));
      }
    }
  }

Now both cases work fine.

Persist operation terminates EntitySet items enumeration 

Saving local changes to storage while EntitySet<T> collection is being enumerated caused an exception due to the modification of collection. For instance,

  using (var domain = Domain.Build(GetDomainConfiguration())
  using (var session = domain.OpenSession())
  using (var transaction = session.OpenTransaction()) {
    //get order with some items
    var order = session.Query.All<Order>().First();
    // locally added item
    order.Items.Add(new OrderItem());

    foreach (var orderItems in order.Items) {
      // there are no changes to the collection performed
      // forces local changes to be saved to storage explicitly
      session.SaveChanges();
    }
  }

And an example of implicit saving of changes

  using (var domain = Domain.Build(GetDomainConfiguration())
  using (var session = domain.OpenSession())
  using (var transaction = session.OpenTransaction()) {
    //get order with some items
    var order = session.Query.All<Order>().First();
    // locally added item
    order.Items.Add(new OrderItem());

    foreach (var orderItems in order.Items) {
      // there are no changes to the collection performed
      // implicit saving
      var orderItemCount = session.Query.All<OrderItem>().Count();
    }
  }

Basically, an EntitySet<T> collection consists of three sets - the first set of items is saved to the database, the second set consists of locally added items and the third one is locally removed items. Two last sets store changes of collection between savings them to the storage. A persist operation (saving changes) merges all the three sets into the first one, which caused an exception during enumeration.

This merge mechanism was changed. Now only user changes can be the cause of enumeration termination. If a user adds or removes something from the EntitySet instance which is being currently enumerated it will break the enumeration. See example below:

  using (var domain = Domain.Build(GetDomainConfiguration())
  using (var session = domain.OpenSession())
  using (var transaction = session.OpenTransaction()) {
    //get order with some items
    var order = session.Query.All<Order>().First();
    // locally added item
    order.Items.Add(new OrderItem());

    foreach (var orderItems in order.Items) {
      //we change contents of the EntitySet
      order.Items.Add(new OrderItem());
    }
  }

Here, the EntitySet<Order> collection was modified during enumeration so it should be terminated.

Another case when user implicitly changes EntitySet is a paired association. For instance, for the model showed below

  [HierarchyRoot]
  public class Order : Entity
  {
    [Field, Key]
    public long Id { get; private set; }

    [Field]
    public EntitySet<OrderItem> Items { get; private set; }

    // some other fields

    public Order(Session session) 
      : base(session)
    {}
  }

  [HierarchyRoot]
  public class OrderItem : Entity
  {
    [Field, Key]
    public long Id { get; private set; }

    [Field]
    [Association(PairTo = "Items")]
    public Order Order { get; set; }

    //some other fields

    public OrderItem(Session session)
      : base(session)
    {}
  }

Order.Items and OrderItem.Order fields will remain in synchronized state. That cause modification of Items collection and if such thing happens during the collection enumeration an exception will show up. The code below is a great illustration.

  using (var domain = Domain.Build(GetDomainConfiguration())  
  using (var session = Domain.OpenSession())
  using (var transaction = session.OpenTransaction()) {
    var order = session.Query.All<Order>().First();
    var newOrder = new Order();

    foreach (var orderItem in order.Items) {
      // remove the orderItem from the Items collection
      orderItem.Order = newOrder; 
    }
  }

On the first iteration orderItem entity becomes removed from order.Items collection and added to  newOrder.Items collection by setting orderItem.Order field. On the second iteration enumerator will detect the order.Items collection is changed and throw an exception.

So now EntitySet enumeration works as it is supposed to and causes no exception unless the collection has been changed by user.

















96 comments:

  1. This comment has been removed by the author.

    ReplyDelete
  2. This comment has been removed by the author.

    ReplyDelete
  3. This comment has been removed by the author.

    ReplyDelete
  4. Thanks for the information you shared, this information is very helpful to me. I will often visit your blog.
    Proship là đơn vị cung cấp tới quý khách hàng dịch vụ vận tải nội địa, dịch vụ chuyển phát nhanh, dịch vụ ship cod, cho thuê xe tải,... uy tín, nhanh chóng và giá rẻ hiện nay tại TPHCM.

    ReplyDelete
  5. Beta Three was founded in 1988, Beta Three is professional audio manufacturer with R&D and producing;rich technicians and advanced R&D centre and www.stuccorepairlasvegasnv.com/

    ReplyDelete
  6. Hey, I am Chang. I and my team are providing support for the users of HP printer related to issues that may occur while printer setup. In case you are also facing such issues. You will get the most appropriate solution by visiting HP Printer Offlineor you may connect to us by dialing our toll free number.
    HP Envy 5540 Printer Offline

    ReplyDelete
  7. Thank you for posting this detailed content. Keep it up!
    Regards | https://realsleep.com/

    ReplyDelete
  8. Hello, If you want to buy your dream home without any brokeage then contact to our team and get exculsive offer.
    Book Now why you are waiting for.
    for more detail visit:- Best Residential Projects in Noida Extension

    ReplyDelete
  9. Thank you for your sharing. Thanks to this blog I can learn more things. Expand your knowledge and abilities. Actually the article is very practical. For instant support related to AOL Desktop Gold Update Error then please contact our team for instant help.

    ReplyDelete
  10. You got a really useful blog. I have been here reading for about an hour. I am a newbie and your success is very much an inspiration for me. For instant support related to QuickBooks Desktop Installation Errors please contact our technical expert for help related to QuickBooks.

    ReplyDelete
  11. I am reading a blog on this website for the first time and I would like to tell you that the quality of the content is up to the mark. It is very well written. Thank you so much for writing this blog and I will surely read all the blogs from now on. I also write blog and my latest blog is QuickBooks Express Web Connect Error

    ReplyDelete
  12. Yeh rishta kya kehlata hai is a hindi reality tv show. If you want to watch it's free episodes
    online or download it's hd episodes than visit here.Hindi Desi Serials will be telecasted live.
    Yeh rishta kya kehlata hai watch online
    Yeh rishta kya kehlata hai watch live
    Yeh rishta kya kehlata hai full episode

    ReplyDelete
  13. quickbooks error 15106 is a typical issue that happens because of difficulty in the update program. It ordinarily suggests that the update program has been upset prompting this unforeseen mistake. You might experience this blunder code on your screen while utilizing it. Relax, you can without much of a stretch fix this blunder with appropriate advances.

    ReplyDelete
  14. There a different variety of datasets available in the market. Each one has some unique identify and features Create an online tv channel

    ReplyDelete
  15. Online video platform providers help businesses and professionals to easily create and manage their video content on the world wide web.

    ReplyDelete
  16. The top online video platform owners have many reasons to provide esteemed services to their approached audience like video sharing, generating leads, building product awareness, marketing, and assisting with paid access facility for video streaming.

    ReplyDelete
  17. Secure Cloud Video Platform that has strict security standards and privacy regulations helps mitigate risks of hacking, piracy

    ReplyDelete
  18. https://vienthucung.com/ noi chia se tat tan tat nhung thong tin xoay quanh the gioi thu cung, vat nuoi hay các loai dong vat.

    ReplyDelete
  19. This was a great release. Thanks for sharing.
    Our site

    ReplyDelete
  20. concrete companies 13201 zip code object-relational mapper (ORM) and business logic layer (BLL) framework.

    ReplyDelete
  21. A great resource in learning programming. bathroom remodeling Finsbury Park

    ReplyDelete
  22. That cause modification of Items collection and if such thing happens during the collection enumeration an exception will show up.
    https://www.google.com/maps?cid=7103629497482529158&_ga=2.141440049.229652753.1638346905-1925002581.1635364277

    ReplyDelete
  23. Contribute to DataObjects-NET/dataobjects-net development by creating an account on GitHub.

    URL: https://www.overlandparkjunkremovalpros.com/

    ReplyDelete
  24. I found a way to work around a project I have been working on recently using the information here. Thank you so much.

    gocryptome.io

    ReplyDelete
  25. Phenol market - Phenol is a pungent natural mixture with the molecular formula C6H5OH and is also known as carbolic acid. Phenol is a chemical solvent extensively used in various places, such as chemistry, biology, and medical laboratories. Moreover, phenol exists in numerous consumer products that are swallowed or rubbed onto several body parts. These commodities include creams, ear and nose drops, cold sore lotions, mouthwashes, gargles, throat lozenges, and antiseptic lotions.

    ReplyDelete
  26. A persist operation (saving changes) merges all the three sets into the first one, which caused an exception during enumeration. auto glass shop

    ReplyDelete
  27. Such an informative site! Thanks for sharing this info. Keep on posting. https://www.bathroomremodelgreensboronc.com

    ReplyDelete
  28. Sometimes inclusion of a static fields in operations like In() or Contains() resulted in the exception. Instance fields are handled correctly though. call us

    ReplyDelete
  29. Hello! Just want to ask if is there any free version of this available?
    usps mail forwarding

    ReplyDelete
  30. Great information, thanks for this. It's a really big help. best regards from https://www.clevelandbathroomremodel.com

    ReplyDelete
  31. A persist operation (saving changes) merges all the three sets into the first one, which caused an exception during enumeration.
    French drain repair San Francisco California

    ReplyDelete
  32. First and foremost, thank you for all of your valuable insights. I'd want to thank you for emphasizing the importance of relevancy in the hosting market. I appreciate all of your efforts. Continue to share new updates with us. | See us

    ReplyDelete
  33. Thanks for sharing a great and wonderful information! I find my website far better than before in a short period of time. See my website now www.sandyspringsfencepros.com

    ReplyDelete
  34. Thank you for this information. Great work.
    Bathroom remodeling

    ReplyDelete
  35. In old times, books were uncommon and a couple of elites can approach books however presently in light of mechanical headway, everybody approaches schooling and data.
    get the assistance with https://trevorlofk068.wordpress.com/2022/09/14/enough-already-15-things-about-an-industry-report-revealed-that-78-of-organizations-saw-team-coaching-in-increasing-demand-were-tired-of-hearing/

    ReplyDelete
  36. Amazing article, Thanks for sharing this one. fencingdundee.co.uk/

    ReplyDelete
  37. Nice to visit such an informative blog. info

    ReplyDelete
  38. This comment has been removed by the author.

    ReplyDelete
  39. Thanks for sharing this information. Keep on posting. info

    ReplyDelete
  40. Love your website. Keep up the good work. ReadMore: Kashmir Tour Packages

    ReplyDelete
  41. It's great to have a new version. Thanks. SEO for Video

    ReplyDelete
  42. DataObjects.Net is a persistence and object-relational mapping framework for the Microsoft .NET. It allows developers to define persistent objects as well as business logic directly in C#, Visual Basic or F#. https://www.iowacityconcretecontractors.com/

    ReplyDelete
  43. These are the things we need to really learn more about.

    https://luminas.com/clinical-study/

    ReplyDelete
  44. Now only user changes can be the cause of enumeration termination.

    Joana | concrete expert

    ReplyDelete
  45. Thanks for sharing so nice information....its a amazing work as well as idea. Kudos! Rick from house cleaning, looking forward to see more.

    ReplyDelete
  46. Thanks for the sharing the useful information. This post is very amazing and useful. You are also read more then click here Online tuition for hindi. Thank You!

    ReplyDelete
  47. Very much appreciated. Thank you for this excellent article. Keep posting!
    Fence service Little Rock

    ReplyDelete
  48. Thanks for sharing such a useful information. It is very helpful article. Very informative blog.
    Tree Removal in Calgary Ab

    ReplyDelete
  49. very informative article!!! thank you so much!

    Red Deer Concrete

    ReplyDelete
  50. Your teaching help us excel in this field and help me find God. All the best!

    ReplyDelete
  51. This is a helpful code. Thanks for sharing. Strive Holistic Massage

    ReplyDelete
  52. Awesome read you’ve got there, I’ll have to pass it on!
    https://plasticsurgerysacramento.net

    ReplyDelete
  53. I am glad I found this article, as it was exactly what I was looking for. I was having trouble finding information on this topic, but this article was very helpful. I appreciate the author for taking the time to write such a comprehensive and informative article.

    thefitnessstudiocharlotte.com

    ReplyDelete
  54. Dr. Dhanesh Agrahari is one of the best Pediatric Surgeon in Prayagraj .I have ever consulted for my kids.

    ReplyDelete
  55. Thanks for sharing this information here. tree trimming

    ReplyDelete
  56. These improvements aim to enhance the functionality and reliability of DataObjects.Net. Users can expect a more stable and efficient experience with these changes in place. Thank you for sharing this update on the software's improvements. blog

    ReplyDelete
  57. It's great information you posted, thanks for the share. junk removal

    ReplyDelete
  58. It seems like you've shared release notes for a new version of DataObjects.Net, highlighting specific changes and improvements made in this update. These changes include fixing scenarios leading to NullReferenceException during query translation, and addressing issues related to the termination of EntitySet items enumeration during the persist operation. https://luckeproperties.com/

    ReplyDelete
  59. Great! Thanks for sharing this one. click

    ReplyDelete
  60. Very informative post. Glad to check this here. plasterer brisbane

    ReplyDelete
  61. Thank you for providing the detailed explanation of the changes made in the new version of DataObjects.Net. It's clear that these changes address specific issues related to query operations and persistence behavior, particularly around handling null references and enumeration of EntitySet items during persistence. cincinnati-seo.com/

    ReplyDelete

  62. Thank you for your kind words! I'm glad you found the article helpful. If you have any specific topics or questions you'd like to see covered in future posts, feel free to let me know. I'm here to help!
    When using essential oils during cold and flu season, it's essential to dilute them properly and use them safely. You can diffuse them in the air, inhale them directly from the bottle, or apply them topically (diluted with a carrier oil) to the chest, back, or feet. Be sure to do a patch test before applying any essential oil to your skin, especially if you have sensitive skin or allergies. If you have any underlying health conditions or are pregnant, consult with a healthcare professional before using essential oils.https://www.rockymountainoils.com/blogs/personal-care/7-essential-oils-for-the-cold-and-flu-season

    ReplyDelete