Data Dictionary and Objects

Listing Objects 

SQL> SELECT  object_name, object_type  FROM  user_objects;

OBJECT_NAME                   OBJECT_TYPE
------------------------      --------------------
ACCOUNTS                      TABLE
ACC_TYP                       TYPE
ADDRESS                       TYPE
ADDRESS_TAB                   TABLE
ADDRESS_TYP                   TYPE
CUSTOMER                      TABLE


Describing Object Type Attributes with the Data Dictionary
Use the SQL*Plus DESCRIBE command to display the attributes of a type. 

SQL> DESC  address_typ; 

Name                    Null?    Type
----------------------- -------- ------------------
ADDRESS1                         VARCHAR2(32)
ADDRESS2                         VARCHAR2(32)
CITY                             VARCHAR2(16)
STATE                            CHAR(2)
ZIP                              CHAR(5)


Information about object type attributes can also be found in the data dictionary tables: ALL_TYPE_ATTRS and USER_TYPE_ATTRS. 

 SQL> DESC  user_type_attrs;

Name                         Null?    Type
---------------------------- -------- -----------------------
TYPE_NAME                    NOT NULL VARCHAR2(30)
ATTR_NAME                    NOT NULL VARCHAR2(30)
ATTR_TYPE_MOD                         VARCHAR2(7)
ATTR_TYPE_OWNER                       VARCHAR2(30)
ATTR_TYPE_NAME                        VARCHAR2(30)
LENGTH                                NUMBER
PRECISION                             NUMBER
SCALE                                 NUMBER
CHARACTER_SET_NAME                    VARCHAR2(44)
ATTR_NO                      NOT NULL NUMBER
INHERITED                             VARCHAR2(3)