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Versioning involves recording and managing changes to a multiuser geodatabase by creating a version of the databasean alternative, independent, persistent view of the database that does not involve creating a copy of the data and supports multiple concurrent editors. Versioning can only be implemented on ArcSDE geodatabases hosted on a database management system (DBMS) platform that supports concurrent multiuser editing. Personal geodatabases, on the other hand, which support only single-user editing, do not support versioning.
In providing versioning functionality, the editing environment also supports edit sessions that typically span a number of days, the facility to undo or redo changes made to the database, "what-if" scenarios, testing and development of data models and alternative application design proposals without affecting the published database, and a facility to monitor how the data and the database have evolved over time.
ArcSDE also provides the capability to support project workflows implemented in many organizations. To better understand the particular challenges of managing concurrent multiuser access to geographic information stored in a DBMS, this section will describe ArcSDE versioning in detail, including DBMS edit transactions, workflows, and reconciling.