Optimistic Concurrency Error In Entity Framework
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Get Started > Optimistic Concurrency Patterns Optimistic concurrency involves optimistically attempting to save your entity to the database in the hope that the
Entity Framework Concurrency Mode
data there has not changed since the entity was loaded. If entity framework pessimistic concurrency it turns out that the data has changed then an exception is thrown and you must resolve the
Entity Framework Turn Off Optimistic Concurrency
conflict before attempting to save again. This topic covers how to handle such exceptions in Entity Framework. The techniques shown in this topic apply equally to models created entity framework optimistic concurrency code first with Code First and the EF Designer.This post is not the appropriate place for a full discussion of optimistic concurrency. The sections below assume some knowledge of concurrency resolution and show patterns for common tasks.Many of these patterns make use of the topics discussed in Working with Property Values.Resolving concurrency issues when you are using independent associations entity framework rowversion (where the foreign key is not mapped to a property in your entity) is much more difficult than when you are using foreign key associations. Therefore if you are going to do concurrency resolution in your application it is advised that you always map foreign keys into your entities. All the examples below assume that you are using foreign key associations.A DbUpdateConcurrencyException is thrown by SaveChanges when an optimistic concurrency exception is detected while attempting to save an entity that uses foreign key associations. Resolving optimistic concurrency exceptions with Reload (database wins)The Reload method can be used to overwrite the current values of the entity with the values now in the database. The entity is then typically given back to the user in some form and they must try to make their changes again and re-save. For example: using (var context = new BloggingContext()) { var blog = context.Blogs.Find(1); blog.Name = "The New ADO.NET Blog"; bool saveFailed; do { saveFailed = false; try { context.SaveChanges(); } catch (DbUpdateConcurrencyException ex) { saveFa
Entity Entity Relationships Entity Lifecycle Code First Model First Database First Choose Dev Approach Querying with EDM Projection Query DBSet Class DBEntityEntry Class Change Tracking Persistence Scenarios CRUD in Connected Mode Disconnected Entities Add
Entity Framework Concurrency Attribute
Single Entity Update Single Entity Delete Single Entity Add Entity Graph Update Entity dbupdateconcurrencyexception Graph Concurrency Stored Procedure in EF CUD using Stored Procedure Migration from EF 4.x Enum Support Spatial Datatypes Table-valued Function
Entity Framework Timestamp Column
Local data Eager Loading Lazy Loading Explicit Loading Raw SQL Query Validate Entity Multiple Diagrams Colored Entities Download Sample Project Previous Next Concurrency in Entity Framework: Entity Framework supports Optimistic Concurrency by default. https://msdn.microsoft.com/en-us/data/jj592904.aspx In the optimistic concurrency, EF saves the entity to the database, assuming that the same data has not changed since the entity was loaded. If it determines that the data has changed, then an exception is thrown and you must resolve the conflict before attempting to save it again. Let's see how to handle optimistic concurrency with Student entity. First of all, you need to http://www.entityframeworktutorial.net/EntityFramework5/handle-concurrency-in-entity-framework.aspx have a rowversion column in the Student table in order to handle concurrency with Student entity. Rowversion is a datatype in the SQL Server that automatically generates unique binary number whenever the insert or update operation is performed in a table. The rowversion datatype is simply an incrementing number. Rowversion is a similar to the timestamp datatype. Create a new column RowVersion in Student table with timestamp datatype as shown below: Note: The value of RowVersion will be added and updated automatically by the database during the Insert and Update operation. Now, create a new Entity Data Model as shown in Create Entity Data Model section or if you already have an EDM then update it by right clicking on designer -> Update Model From Database -> Refresh Student table. Now, you will see the RowVersion property added in the Student entity. Then, you need to set the concurrency mode to fixed by right clicking on RowVersion property in the Student entity (right click on RowVersion property not Student entity) -> select Property. Change Concurrency Mode to Fixed from None in the property window as shown below: EF will now include a RowVersion column in
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site http://stackoverflow.com/questions/22035630/concurrency-exceptions-in-entity-framework About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss http://www.codeproject.com/Tips/743507/Detecting-concurrency-issues-with-Entity-Framework Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Concurrency exceptions in entity framework Entity Framework up vote 14 down vote favorite When calling SaveChanges / SaveChangesAsync in Entity Framework (CF, C#), if a change conflict occurs (for example, the values has been updated since last read thingy), then which of these two exceptions DbUpdateConcurrencyException OR OptimisticConcurrencyException shall I catch? And what is the difference between them? c# entity-framework entity-framework-6 optimistic-concurrency share|improve this question edited Feb 26 '14 at entity framework concurrency 8:36 marc_s 454k938711033 asked Feb 26 '14 at 8:25 Flair 755816 In the light of the answer you got - have you even considered, just for a second, looking up the exceptions in the documentation and reading those descriptions? You basically ask to quote the documentation. –TomTom Feb 26 '14 at 8:43 4 Of course, I read the documentation, but it doesn't make much sense to me, as both of them looks quite similar. 'use it when optimistic concurrency exception can occur'. Hence I gave a situation in my question and asked in that context! –Flair Feb 26 '14 at 8:49 add a comment| 2 Answers 2 active oldest votes up vote 9 down vote accepted DbUpdateConcurrencyException is a specific exception thrown by DbContext, so this is the one to catch. This exception may be caused by an underlying OptimisticConcurrencyException, but if so, this exception is wrapped as the inner exception. Not all update exceptions are caused by concurrency, so you also have to catch DbUpdateException after catching DbUpdateConcurrencyException (because the latter is a subtype of DbUpdateException). See also Entity framework 5.0 handle optimistic concurrency exception?. share|improve this answer answer
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