You successfully executed these commands:
connect scott/tiger@prod1;
CREATE DATABASE LINK db_prod2
CONNECT TO scott IDENTIFIED BY tiger
USING 'PROD2';
Which type of database link is created?
A)private current user database link
B)public connected user database link
C)public current user database link
D)private fixed user database link
E)public fixed user database link
Answer: D
赵：
总结：
默认创建的是 private connect，create 子句中没有这两个关键字，是 private connected 类型的;
Create 子句中有 public 关键字的是 public 类型的;
Create 子句中有 current_user 关键字的是 current 类型的;
Create 子句中有 identified by 关键字的是 fixed 类型的;
资料：blog-itpub-net/31397003/viewspace-2137245/
PDF 上有个表格没复制过来。
CREATE [SHARED][PUBLIC] database link link_name
[CONNECT TO [user][current_user] IDENTIFIED BY password]
[AUTHENTICATED BY user IDENTIFIED BY password]
[USING 'connect_string']
Dblink 分三类：用户级(private)、数据库级(public)、网络级。
默认情况下创建的是用户级(private)。
另参考：www-cnblogs-com/sumsen/archive/2013/03/04/2943471.html
几种类型DBLINK创建示例：
--Private connected user
CREATE database link
sales.us.americas.acme_auto.com USING ‘sales_us’;
--Private current user
CREATE database link foo
CONNECT TO CURRENT_USER USING ‘am_sls’;
--Private fixed user
CREATE database link
sales.us.americas.acme_auto.com
CONNECT TO scott IDENTIFIED BY tiger USING ‘sales_us’;
--Public fixed user
CREATE PUBLIC database link
sales CONNECT TO scott IDENTIFIED BY tiger USING ‘rev’;
--Shared public fixed user
CREATE SHARED PUBLIC database link
sales.us.americas.acme_auto.com
CONNECT TO scott IDENTIFIED BY tiger AUTHENTICATED BY
anupam IDENTIFIED BY bhide USING ‘sales’;