从DICTIONARY开始，这个数据对象包含了数据字典的表名和说明

DESCRIBE DICTIONARY

SELECT*

FROM   dictionary

WHERE  table_name= ‘USER_OBJECTS‘;

USER_OBJECTS:

USER_OBJECTS视图：

SELECTobject_name,object_type,created, status

FROM   user_objects

ORDERBY object_type;

ALL_OBJECTS:

USER_TABLES 用户自己的表:

DESCRIBE user_tables

SELECTtable_name

FROM   user_tables;

DESCRIBEuser_tab_columns

SELECT column_name,data_type,data_length,

       data_precision,data_scale,nullable

FROM   user_tab_columns

WHERE  table_name= ‘EMPLOYEES‘; 

DESCRIBE user_constraints

SELECT constraint_name,constraint_type,

       search_condition,r_constraint_name,

       delete_rule,status

FROM   user_constraints

WHERE  table_name= ‘EMPLOYEES‘; 

DESCRIBE user_cons_columns

SELECT  constraint_name,column_name

FROM   user_cons_columns

WHERE  table_name= ‘EMPLOYEES‘; 

DESCRIBE user_views

SELECTDISTINCT  view_nameFROM user_views;

SELECT  text FROM user_views

WHERE  view_name= ‘EMP_DETAILS_VIEW‘;

DESCRIBE  user_sequences

SELECT  sequence_name,min_value,max_value,

  increment_by,last_number

FROM  user_sequences;

同义词

DESCRIBE user_synonyms

SELECT*

FROM   user_synonyms;

给表添加注释