SINGLE-OPERATION ON-LINE SCHEMA EVOLUTION

摘要

A method for modifying an original data object in a database using a single command is disclosed. The single command is first validated. Once the command has been validated a ghost data object is created using the new definition. The ghost data object is populated with data from the original object. The transaction log records from the original data object are applied to the ghost data object. The original data object is then locked for exclusive access. The final transaction log records from the original data object are applied to the ghost data object. In the final step the database switches to the new data object. Dependent objects are automatically transformed as part of the same operation.