optimistic-concurrency

问题 i'm developping a PHP service that need to get a unique TOKEN from a MySQL table. The table is like: ID TOKEN ID_PROCESS 1 AAAAA 0 2 BBBBB 0 3 CCCCC 0 The table has millions of records with already generated TOKEN. I need to be extra sure that, for example, the record with ID = 1 is selected and then updated ( UPDATE table set ID_PROCESS = 123 WHERE ID = 1) from one user and that nobody else could select it and then update it overwriting the former update. For selecting an available TOKEN i

问题 i'm developping a PHP service that need to get a unique TOKEN from a MySQL table. The table is like: ID TOKEN ID_PROCESS 1 AAAAA 0 2 BBBBB 0 3 CCCCC 0 The table has millions of records with already generated TOKEN. I need to be extra sure that, for example, the record with ID = 1 is selected and then updated ( UPDATE table set ID_PROCESS = 123 WHERE ID = 1) from one user and that nobody else could select it and then update it overwriting the former update. For selecting an available TOKEN i

问题 I am simulating multiple concurrent request for MongoDB`s "update". Here is the thing, I insert a data amount=1000 in mongoDB, and every time I trigger the api, it will update the amount by amount += 50 and save it back to database. Basically it is a find and update operation on a single document. err := globalDB.C("bank").Find(bson.M{"account": account}).One(&entry) if err != nil { panic(err) } wait := Random(1, 100) time.Sleep(time.Duration(wait) * time.Millisecond) //step 3: add current

问题 I am updating a single column in a table using Linq, take fictitious table below. MyTable (PKID, ColumnToUpdate, SomeRandomColumn) var row = (from x in DataContext.MyTable where b.PKID == 5 select x).FirstOrDefault(); row.ColumnToUpdate = 20; DataContext.SubmitChanges(); This updates the column to as expected, no surprises here. However when I inspect the SQL commands which are generated, it does this: UPDATE [dbo].[MyTable ] SET [ColumnToUpdate ] = @p2 WHERE ([PKID] = @p0) AND (

问题 I am migrating a SQL Server database schema over to MySQL. Some of the tables on SQL Server have a column of type rowversion. This is an integer value that is set when the row is first inserted and then again each time any column of the row is updated. The number is only ever incremented. We make use of this to check for concurrency problems. So when an insert comes to the server we can check if the incoming value is different to the current stored value. If so, then the row has been updated

问题 I am migrating a SQL Server database schema over to MySQL. Some of the tables on SQL Server have a column of type rowversion. This is an integer value that is set when the row is first inserted and then again each time any column of the row is updated. The number is only ever incremented. We make use of this to check for concurrency problems. So when an insert comes to the server we can check if the incoming value is different to the current stored value. If so, then the row has been updated

问题 I have a EF code first context which represents a queue of jobs which a processing application can retrieve and run. These processing applications can be running on different machines but pointing at the same database. The context provides a method that returns a QueueItem if there is any work to do, or null, called CollectQueueItem . To ensure no two applications can pick up the same job, the collection takes place in a transaction with an ISOLATION LEVEL of REPEATABLE READ . This means that

问题 I have a problem updating a foreign key in an Entity Framework entity. I am using self tracking entities and have an entity with some relations where the foreign key is also present as a property (one of the new features of EF4). The key (an integer) is marked as Nullable and Concurrency Mode fixed. Specifically I have an Alarm entity with a many to 0..1 relationship to a confirming user. (a user may confirm several alarms, but an alarm can be confirmed by only zero or one users). The entity

问题 i have the following action method inside my asp.net mvc web application , which will raise a DbUpdateConcurrencyException as intended to handle any concurrent conflicts that might happen:- [HttpPost] public ActionResult Edit(Assessment a) { try { if (ModelState.IsValid) { elearningrepository.UpdateAssessment(a); elearningrepository.Save(); return RedirectToAction("Details", new { id = a.AssessmentID }); } } catch (DbUpdateConcurrencyException ex) { var entry = ex.Entries.Single(); var

问题 I'm trying to use a DateTime LastModifiedDate column with optimistic concurrency in Entity Framework (will likely upgrade it to DateTime2.) I've set the Concurrency Mode to Fixed. But when I retrieve an entity, change a column and try to save, get a concurrency exception. The stored LastModifiedDate is 2017-01-04 21:16:55.283 but look at the SQL Entity Framework is generating for the update: UPDATE [dbo].[Facilities] SET [Password] = @0 WHERE (([pk_FacilityID] = @1) AND ([LastModifiedDate] =