Optimistic concurrency control: Difference between revisions

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Web usage: opaque token -> opaque token -- this is an important concept
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The [[Stateless server|stateless]] nature of [[HTTP]] makes locking infeasible for web user interfaces. It's common for a user to start editing a record, then leave without following a "cancel" or "logout" link. If locking is used, other users who attempt to edit the same record must wait until the first user's lock expires.
 
OCC is a natural choice. It is simple to implement and avoids unnecessary waiting or silently overwritten records. Typically the [[Form (web)|form]] presented to the user includes a hidden field with the record's original content, a timestamp, a sequence number, or an [[opaque token]]. On submit, this is compared against the database. If it differs, the conflict resolution algorithm is invoked.
 
===Examples===