Data occurrences or instances. Data model describes the structures of a DB and the operations that can be done on it. This is a definition of the DB by intension . These are the values for all the attributes in the table. Conceptual level is a global description of the DB for the entire community of users.
Different packages come with different utilities for housekeeping.
Backup, e.g. onto tape. Report generation, may include graphics capabilities. Performance monitoring speed of queries, etc. 6.