As you can see, with pessimistic concurrency control steps must be taken to ensure that data isn't inadvertently locked and therefore unable to be modified by other users.Because of these challenges and the diminished user experience that follows, pessimistic concurrency control is rarely used.This article is one in a series of articles on ASP. This type of behavior is known as "last write wins" and is the default behavior for web applications."Last write wins" is sufficient in applications where it is very rare for two users to be simultaneously working on the same data.The following figure illustrates this workflow when Manager A - the manager who updates the unit price to .00 - clicks the Update button after Manager B has already saved his changes.As noted in the Introduction, this behavior is termed "last write wins," and is the default behavior of the Sql Data Source control (and most web applications, for that matter).
If you fail to complete the purchase by then - either because you go out to lunch or are just too slow in entering your information - the seat is "unlocked" and returned to the general pool. NET does not offer any built-in support for pessimistic concurrency control.This means that we can be certain that the last scenario won't unfold.Therefore, whatever manager clicks the Update button last will have his or her changes saved, overwriting the other's.These policies may add friction to the end user's data entry experience.Microsoft offers a form of optimistic concurrency control from the Sql Data Source control that can be enabled by ticking a checkbox.