Users frequently create tables before importing data to reorganize tablespace usage or to change a table's storage parameters. The tables must be created with the same definitions as were previously used or a compatible format (except for storage parameters). For object tables and tables that contain columns of object types, format compatibilities are more restrictive.
For object tables and for tables containing columns of objects, each object the table references has its name, structure, and version information written out to the export file. Export also includes object type information from different schemas, as needed.
Import verifies the existence of each object type required by a table before importing the table data. This verification consists of a check of the object type's name followed by a comparison of the object type's structure and version from the import system with that found in the export file.
If an object type name is found on the import system, but the structure or version do not match that from the export file, then an error message is generated and the table data is not imported.
The Import parameter
TOID_NOVALIDATE can be used to disable the verification of the object type's structure and version for specific objects.