Object Conversion

Object conversion is the reorganization phase that coerces objects into a form that is compatible with the class definition in the latest schema version. This phase does not consider relationships between objects; rather structural changes affecting individual objects only are performed. While objects are being converted during this phase, applications can access and update objects defined by the current schema version without restriction.

The system remains available while the following changes are performed.

• Adding and removing attributes

• Adding and removing embedded references

• Adding and removing exclusive collections

• Changing the type of an attribute (any combination of type-to-type conversion)

• Changing the length of String or Binary attributes (includes converting embedded String or Binary primitive types to string large objects (slobs) or binary large objects (blobs), respectively, and the reverse, and truncation)

• Changing the precision or scale factor of a decimal attribute

• Moving blob and slob attributes up or down the class hierarchy

• Removing all inverses from a relationship (that is, after the change, there are no inverses between the properties that were involved in the relationship)

When all objects have been converted to their new state, any applications, including server applications, must be shut down that are accessing the schema or class being reorganized.