The storage and management of previous versions of a piece of information, for security, diagnostics, and interest This is important when many users are allowed to edit the same material
With frameworks, schemes to implement backward and forward compatibility of frameworks Versioning information is written into a framework's dynamic shared library and is also reflected in the internal structure of a framework See also major version, minor version
Each transaction is restricted to a view of the database as of the time that transaction started, and when a transaction modifies a record, the DBMS creates a new record version instead of overwriting the old record Hence no form of locking is required (12)
There is no form of locking Each transaction is restricted to a view of the database as of the time that transaction started, and when a transaction modifies a record, the DBMS creates a new record version instead of overwriting the old record