Concurrency error when deleteing or updating multiple primary key fields 100 free meet fucksites
In that case, you don't have to configure the application to handle concurrency conflicts.If your application does need to prevent accidental data loss in concurrency scenarios, one way to do that is to use database locks. For example, before you read a row from a database, you request a lock for read-only or for update access.This tutorial shows how to handle conflicts when multiple users update the same entity at the same time.You'll create web pages that work with the Department entity and handle concurrency errors.
In that case the code uses the posted form values to create a department entity so that the Edit page can be redisplayed with an error message. code-html] Run the app and go to the Departments Index page.Change a field in the first browser tab and click Save. You see the saved values when the Index page appears.The browser shows the Index page with the changed value. For the Delete page, the Entity Framework detects concurrency conflicts caused by someone else editing the department in a similar manner.If you lock a row for update access, no other users are allowed to lock the row either for read-only or update access, because they would get a copy of data that's in the process of being changed. It requires significant database management resources, and it can cause performance problems as the number of users of an application increases.If you lock a row for read-only access, others can also lock it for read-only access but not for update. For these reasons, not all database management systems support pessimistic concurrency.If this flag is true and the Department does exist, it was changed by another user.In that case, the code sends an error message to the view using to give the Http Post method a unique signature.If you don't enable the detection of such conflicts, whoever updates the database last overwrites the other user's changes.In many applications, this risk is acceptable: if there are few users, or few updates, or if isn't really critical if some changes are overwritten, the cost of programming for concurrency might outweigh the benefit.For information about the tutorial series, see the first tutorial in the series.In earlier tutorials, you learned how to update data.