Oracle's Common Data dictionary

One, the Oracle data dictionary is composed of the following views mainly:
1.user View
Use User_ as a prefix to record information about user objects

2.all View
All_, which is used to record the information of the user object and the object information that is authorized to access.

3.DBA View
Prefixed with Dba_ to record information for all objects of the DB instance

4.v$ View
Prefixed with v$, used to record performance statistics related to database activity dynamic information

5.gv$ View
Prefixed with gv$ to record dynamic information for all instances in a distributed environment

Second, Oracle's Common data dictionary
1. Basic Data dictionary
Dictionary name Description
Dba_tables All table information for all users
Dba_tab_columns field information for all users ' tables
Dba_views All view information for all users
dba_synonyms all synonym information for all users
Dba_sequences all sequence information for all users
dba_constraints constraint information for all users ' tables
Dba_ind_columns field information for the index of all users ' tables
Dba_triggers trigger information for all users
Dba_sources stored procedure information for all users
Dba_segments use space information for all users ' segments
Dba_extents extended information for all segments of a user
Dba_objects basic information for all user objects
All base tables that the cat current user can access
tab all base tables, views, synonyms, etc. created by the current user
Dict information for all tables that comprise a data dictionary

2. Data dictionaries related to database components
Table or view description in the database component data dictionary
The operation of database V$datafile record system
Table Space Dba_tablespaces The basic information of the record system tablespace
Dba_free_space to record free space information for a system table space
Basic information of control file V$controlfile record system control file
V$control_record_section record the information of a document segment in a system control file
V$parameter basic information for recording system parameters
Data file Dba_data_files record system data file and table space basic information
V$filestat Record data file information from a control file
V$datafile_header basic information for recording data file headers
Section dba_segments basic information for record segments
Section dba_extents basic information for recording data area
Log v$thread basic information for logging threads
V$log basic information for logging log files
V$logfile Log File summary information
Archive V$archived_log basic information for archived log files
V$archived_dest record the path information for the archived log file
DB instance v$instance the basic information of the record instance
V$system_parameter record the current valid parameter information for an instance
Memory structure V$SGA records information about the SGA area
V$sgastat to record SGA details
V$db_object_cache Record object Cache size information
V$sql log details of SQL statements
V$sqltext statement information that records SQL statements
V$sqlarea Log SQL basic information for SQL area
Background process v$bgprocess Show background process information
V$session Displaying current session information

3. Common Dynamic Performance views
View name Description
V$fixed_table displays a description of the currently released fixed object
V$instance displaying information for the current instance
V$latch Display LATCH Statistics
V$librarycache displaying statistics about library cache performance
V$rollstat show the name of the online rollback segment
V$rowcache Show statistics for active data dictionaries
V$sag Record the SGA area information
V$sgastat to record SGA details
V$sort_usage shows the size and session of the staging segment
V$sqltext statement information that records SQL statements
V$sqlarea Log SQL basic information for SQL area
V$stsstat displaying basic instance statistics
V$system_event Displays the total wait time for an event
V$WAITSTAT Display Block Competition statistics

Oracle's Common Data dictionary