(Alex note) Using Data Dictionary and Dynamic Performace View

Data dictionary (read-only / in system tablespace / owned by sys / maintained by Oracle / Accessed with select )
#当执行DDL语句的时候Oracle 自动会对数据字典进行维护.
#DD view is the static view , not means absolutely static.

    1. Base tables (created with sql.bsq script)
        #一般不用太了解。
    #they are created when create database.

    2. Data dictionary views(created with catalog.sql script)
        a. DBA: What is in all the schemas(All of the objects in the database)
        b. ALL: What the user can access(Objects accessible by the current user)
        c. USER: What is in the user's schema(Objects owned by the current user)
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#List all the tables
select table_name from dictionary;
-----------------------
#Below object are most important
schema objects:  DBA_TABLES, DBA_INDEXS, DBA_TAB_COLUMNS, DBA_CONSTRANTS
space allocation: DBA_SEGMENTS, DBA_EXTENTS
db structure: DBA_TABLESPACES, DBA_DATA_FILES

Dynamic Performace tables (dft)
Owner: sys  ; user can't use it
-----------------------
#list all the dinamic table from v$fixed_table
desc v$fixed_table;
select  name from v$fixed_table;
-----------------------
X$ : basic table
GV$: grolb ...

#Below object are most important
V$CONTROLFILE
V$DATABASE
V$DATAFILE
V$INSTANCE
V$PARAMETER : all the parameter that in memory
V$SESSION
V$SGA
V$SPPARAMETER  : SPFILE'S parameter
V$TABLESPACE
V$THREAD : redo log informations
V$VERSION

#Admin script naming
#$ORALCE_HOME/dbms/admin/
cat*.sql : catalog and data dictionary information
dbms*.sql : database package specifications
prvt*.plb : wrapped database package code
utl*.sql : view and tables for database utilities


    
PL/SQL packages
    
    
    
Database event triggers