Name
Version Number Pattern
Goal
Provide a simple way to detect when an object has changed (Figure B-21).
Participants
- Versioned object
Provides an object representation of data subject to change control, and tracks the changes that occur to the data.
- Business tier code
Uses the version number to determine when to persist the versioned object.
Interactions
When an application modifies a property on a versioned object, a version number associated with the object is incremented. Other code can record this version number and use the information to resolve concurrency problems, such as change detection in an optimistic concurrency implementation.
Notes
See related patterns IsDirty and Optimistic Concurrency.
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