我的用户下有个连接别的oracle库的dblink，但是我怎么能知道它的密码呢？
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dblink的密码在user_db_links中是明码存放的，自己去看看就知道了
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1.当初建立的时候用:
create public database link 'test' using 'test';
来建立的话，也不可知道对方的用户的密码.
如建立时有写明的话，可在 user_db_links 查到.
2. 默认的话，有scott/tiger, system/manager,sys/change_on_install
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to chanet(牧师），你写的那个建立databaselink的方法可行吗？
测试结果：
SQL> show user
User is "SYS"
SQL>
SQL> create public database link test using 'db92n1'
2 ;
Database link created
SQL> select * from dba_users@test;
select * from dba_users@test
ORA-01005: null password given; logon denied
SQL> create public database link test1 connect to system identified by system using 'db92n1';
Database link created
SQL> select * from dba_users@test1;
USERNAME USER_ID PASSWORD ACCOUNT_STATUS LOCK_DATE EXPIRY_DATE DEFAULT_TABLESPACE TEMPORARY_TABLESPACE CREATED PROFILE INITIAL_RSRC_CONSUMER_GROUP EXTERNAL_NAME
------------------------------ ---------- ------------------------------ -------------------------------- ----------- ----------- ------------------------------ ------------------------------ ----------- ------------------------------ ------------------------------ --------------------------------------------------------------------------------
SYS 0 E4FAE552BA8F0312 OPEN SYSTEM TEMP_1 2004-5-24 1 DEFAULT SYS_GROUP
SYSTEM 5 970BAA5B81930A40 OPEN SYSTEM TEMP_1 2004-5-24 1 DEFAULT SYS_GROUP
OUTLN 11 4A3BA55E08595C81 OPEN SYSTEM TEMP_1 2004-5-24 1 DEFAULT DEFAULT_CONSUMER_GROUP
DBSNMP 19 E066D214D5421CCC OPEN SYSTEM TEMP_1 2004-5-24 1 DEFAULT DEFAULT_CONSUMER_GROUP
LIFANGJUN\LIFANGJUN 44 EXTERNAL OPEN SYSTEM TEMP_1 2004-5-28 1 DEFAULT DEFAULT_CONSUMER_GROUP
GUEST2 53 EFBB14329F20F8C0 OPEN SYSTEM TEMP_1 2004-9-9 14 DEFAULT DEFAULT_CONSUMER_GROUP
CSMIG 45 09B4BB013FBD0D65 OPEN SYSTEM TEMP_1 2004-6-21 1 DEFAULT DEFAULT_CONSUMER_GROUP
GUEST1 46 C86CC6C6B78AC211 OPEN USERTBS TEMP_1 2004-7-26 1 DEFAULT DEFAULT_CONSUMER_GROUP
OMS 51 4BF4EB98E1BBA6D5 OPEN SPDATA TEMP_1 2004-9-3 16 DEFAULT DEFAULT_CONSUMER_GROUP
WMSYS 21 7C9BA362F8314299 EXPIRED & LOCKED 2004-5-24 1 SYSTEM TEMP_1 2004-5-24 1 DEFAULT DEFAULT_CONSUMER_GROUP
10 rows selected
SQL>
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to drabit(square),可行~
前提是：A 数据库与 B 数据库连接的用户名和密码要相同.
如: select * from scott.emp@b;