有什么工具可以直接查看oracle数据库中表直接的关联关系？？？

Question

是不是查询有主、外键关系的表啊？如果是，那主要是查约束表user_constraints如：
SQL> select b.table_name parent,a.table_name child
  2  from user_constraints a,user_constraints b
  3  where a.R_CONSTRAINT_NAME=b.CONSTRAINT_NAME ;PARENT                         CHILD
------------------------------ ------------------------------
CABLE_DISC                     CASE
CABLE_DISC                     MDF
CASE_DISC                      CABLE_DISC
CASE_DISC                      CABLE_DISC
CASE_DISC                      CASE
CASE_DISC                      CASE
CASE_DISC                      MDF
JDDM                           JDDM_CASE
JDMB                           CASE_DISC
JDMB                           HM_SB
YYQBHB                         JDDM
YYQBHB                         JDMB
YYQBHB                         TEL_USR
YYQBHB                         TEL_USR_APPL已选择14行。