The Data Dictionary
The data dictionary contains the metadata (the data about data) for an Oracle database. The contents of the data dictionary are available through a series of built-in dictionary views. Many of the views are restricted to the database administrator (DBA), but there are other views that are an excellent source of information for the user. What views are there in the dictionary that are available from your account? The table that shows all the dictionary views you can access is called “Dictionary.” The public synonym for Dictionary is “Dict.”
Before doing a SELECT * FROM Dict, be aware that this simple query will give too much information at one time. As we suggested earlier, it is best to approach large tables cautiously. ...