This chapter serves two purposes. First, we look at constraint information in the data dictionary, specifically the data dictionary views USER_CONSTRAINTS and USER_CONS_COLUMNS. An understanding of these views can be a basis for a broad understanding of how constraints are enforced by Oracle. Second, this is a starting point for exploring the data dictionary. You will be able to extract a wide variety of information from the data dictionary: constraint information, triggers, stored procedures, sequence definitions. Anything you define in the database you can reverse-engineer with SQL. The sample scripts in this chapter contain sample output assuming they were run against the DDL for the model in Chapter 4. |