When we need to cross the local database and access the data of the remote database, Oracle provides the dblink method, so that we can easily access the remote database as convenient as the local, let's take a look at the method of creating dblink.
Step 1: First check whether the current user has the permission to create dblink, if not, it needs to be authorized
select * from user_sys_privs t where t.privilege like upper('%link%'); command query, you can see from the result that the current user has create permission
CREATE DATABASE LINK--The dblink created can only be used by the creator, and cannot be used by other users
CREATE PUBLIC DATABASE LINK--public means that the created dblink can be used by all users
Granting needs to execute grant create public database link, create database link to myAccount under sys;
Step 2: Use the following sql to create
create database link HSDblink1 connect to SBD_CXTJ identified by huawei123 using '(DESCRIPTION =(ADDRESS_LIST =(ADDRESS =(PROTOCOL = TCP)(HOST = 192.168.101.5)(PORT = 1521)))(CONNECT_DATA =(SERVICE_NAME = search)))';
TestDblink: Indicates the name of dblink
dbName: indicates the user of the remote database
dbPassword: indicates the password of the remote database
HOST: Indicates the remote database IP
PORT: Indicates the remote database port
SERVICE_NAME: the instance name of the remote database
Step 3: The SERVICE_NAME of the remote database can be queried under the sys user of the remote database
select name,value from v$parameter where name='service_names'
Step 4: Use dblink to access the remote database, the query is the same as the local
select * from teacher@HSDBLINK1;---teacher is the table name, HSDBLINK1 is the created dblink name
