When describing or dropping a table with a user-defined type column table, the following error may occur:
This can happen with any user-defined type, including the ESRI Spatial Type for Oracle (ST_Geometry), under certain circumstances.
Dropping a user that created a table in a second user's schema with a user-defined type owned by a third user can make the table indescribable.
Below is the scenario that causes this problem:
1. User A creates a type, and creates a public synonym for the type so other users are not required to qualify the type with the owner name when creating new tables.
2. User B, who has privileges to create tables in other schemas, creates a new table in user C's schema. The table includes a column whose type is declared, using the non-qualified public synonym of the type owned by user A.
3. User B is dropped.
4. Attempting to describe the table owned by user C results in the following error:
"ORA-00600: internal error code, arguments: , [nnnnnnn], , , , , , ".
5. Attempting to drop the table may also result in the following error: "ORA-00600: internal error".
Notice that user A, the owner of the type, was not dropped. The type, and the synonym for the type were not dropped either. Only the user, such as user B that created the table in another user's, such as user C's schema, was dropped.