||Contains every Tables, View and Synonym.
||All Object-Oriented Tables.
||comments for every Table, which are usually a short description of the Table.
||All owner Privileges, including PUBLIC('everyone').
||Privileges granted by others to others.
||All Object Types.
||All Object Types that are Methods.
||Names and Create Dates for all Users.
||This item is in bold because it is very important.
If you know nothing, you can start with 'SELECT * FROM DATA_DICT'.
It is a top-level record of everything in the Data Dictionary.
||Remaining Free Space in each Tablespace.
A DBA typically spends a lot of time increasing Free Space as Databases
have to hold more data than originally planned.
||All Tables, Views and Synonynms that the currently logged-in User can see.
||Details of User-specific Indexes.
||Details of User-specific Tables, with some statistics, such as record counts.
||Details of Columns within each User Table, which is very useful when you want to find
the structure of your Tables.
||Details of User-specific Privileges for Table access.
||Details of User-specific Views, and the SQL for each View,(which is essential).