optimistic-concurrency

问题 I've been trying to use ISession.Merge() to keep coherence between two sessions, but it fails when the merged instance has a higher Version property than the one loaded in the session (with a StaleObjectStateException). Is there an alternative method that would work when the Version fields do not match ? 回答1: Try calling: Session.Lock(string entityName, object obj, LockMode lockMode); with LockMode.Force. The remarks for that method state: This may be used to perform a version check

问题 Scenario: We have a Dynamo DB table supporting Optimistic Locking with Version Number. Two concurrent threads are trying to save two different entries with the same primary key value to that Table. Question: Will ConditionalCheckFailedException be thrown for the latter save action? 回答1: Yes, the second thread which tries to insert the same data would throw ConditionalCheckFailedException . com.amazonaws.services.dynamodbv2.model.ConditionalCheckFailedException As soon as the item is saved in

问题 I found an MSDN article that describes how EF handles concurrency when saving changes: By default [...] Object Services saves object changes to the database without checking for concurrency . For properties that might experience a high degree of concurrency, we recommend that the entity property be defined in the conceptual layer with an attribute of ConcurrencyMode="fixed" I have two questions: Having no properties in my model where ConcurrencyMode="fixed" , is it safe for me to assume that

问题 I am trying to implement the solution given in Handling Concurrency with the Entity Framework in an ASP.NET MVC Application . The article says: Adding a Tracking Property to the Department Entity In Models\Department.cs, add a tracking property: [Timestamp] public Byte[] Timestamp { get; set; } The Timestamp attribute specifies that this column will be included in the Where clause of Update and Delete commands sent to the database. Since I'm using a model first approach, I followed steps 1 -

问题 A StaleObjectStateException is being thrown in my app instead of OptimisticLockException (as I read I should expect this one) when optimistic concurrency problem occurs in my app. No need to post code, as it's the most basic concurrency problem - wrong version in a timestamp column. How am I supposed to get OptimisticLockException, not the other one? 回答1: StaleObjectStateException is thrown when you use straight hibernate API. OptimisticLockException is thrown if you used JPA style hibernate.

问题 We have an ASP.Net MVC application that uses EF4 as its data access layer and we're seeing unexpected behaviour with regards to OptimisitcConcurrencyExceptions not being thrown when we think they should be. We have simplified the problem down to the following code... using System.Linq; using Project.Model; namespace OptimisticConcurrency { class Program { static void Main() { Contact firstContact = null; using (var firstEntities = new ProjectEntities()) { firstContact = (from c in

问题 I'm using a timestamp column to check the concurrency in my entity. The exception is correctly thrown when data is not the same in 2 different contexts. When such an exception occurs when saving, I call the following method to handle it: public static void HandleOptimisticConcurrencyException(ObjectContext context, OptimisticConcurrencyException ex) { string msg = @"The data has changed while you were editing it. If you save, your changes will override the previous ones. If you don't, your

问题 BACKGROUND Assume you have a (SOAP) web service, BookService , managing books in a library. In the information model assume that the Book entity has the following attributes: id author publisher title shelfId In order to manipulate the data four web service operations are defined: AddBook GetBook UpdateBook DeleteBook Request and response message are defined for each operation. However, the design of the update message XML schemas is more complicated. We would like to achieve the following

问题 With RavenDB, creating an IDocumentSession upon app start-up (and never closing it until the app is closed), allows me to use optimistic concurrency by doing this: public class GenericData : DataAccessLayerBase, IGenericData { public void Save<T>(T objectToSave) { Guid eTag = (Guid)Session.Advanced.GetEtagFor(objectToSave); Session.Store(objectToSave, eTag); Session.SaveChanges(); } } If another user has changed that object, then the save will correctly fail. But what I can't do, when using

问题 Is there a way to set optimistic concurrency to true in Raven.Server.exe.config? Or, can it somehow be applied at the database level? On RavenDB's site, I see a couple of mentions of setting UseOptimisticConcurrency = true, but it looks like it's at the session level within the code: public void Save<T>(T objectToSave) { using (IDocumentSession session = Database.OpenSession()) { session.Advanced.UseOptimisticConcurrency = true; // This is the setting Guid eTag = (Guid)session.Advanced