Purpose
This statement is used to create a dblink that accesses a specified remote database. The statement requires specifying the name of the dblink and providing the username, tenant name, password, IP address, port number, and access type of the remote database. For a reverse link, the username, tenant name, password, IP address, and port number of the local database are also required. If the access type is not specified, the dblink will default to accessing a remote OceanBase Database.
If the remote database is an OceanBase Database, the IP address and port number can be those of an OBServer node in the specified OceanBase cluster or the IP address and port number of the Proxy of the OceanBase cluster. When the port number of the dblink is the port number of the Proxy and the Proxy is deployed via ConfigUrl, the cluster name must be specified. For reverse link functionality, the IP address and port number of an OBServer node in the local OceanBase cluster, along with the username, tenant name, and password, must also be provided.
If the remote database is an Oracle database, the access type must be explicitly specified as OCI, and the oracle_sid must be provided. The tenant name must be oracle.
Syntax
CREATE DATABASE LINK dblink_name CONNECT TO user_name@tenant_name
IDENTIFIED BY password_str [OB|OCI] HOST 'ip:port[/oracle_sid]' [CLUSTER cluster_name] [MY_NAME local_user_name@local_tenant_name
IDENTIFIED BY local_password_str HOST 'local_ip:local_port'];
Considerations
Field |
Description |
|---|---|
| dblink_name | Specifies the name of the database link to be accessed. |
| user_name | Specifies the username of the remote database. |
| tenant_name | Specifies the tenant name of the remote database. If the remote database is an Oracle database, the tenant name is always oracle. |
| password | Specifies the login password for the username of the remote database. If the password contains special characters other than digits and letters (~!@#%^&*_-+=|(){}[]:;,.?/), double quotes must be used to enclose the password to avoid syntax errors. |
| OB | OCI | OB specifies the remote database type as OceanBase Database, and OCI specifies the access type as Oracle. If neither parameter is provided, the default remote database type is OceanBase Database. |
| ip | Specifies the IP address of the remote database. If the remote database is an OceanBase Database, the IP address can be that of the Proxy or an OBServer node in the cluster. If the IP address is specified as that of an OBServer node, the network between the local database and the specified OBServer node must be accessible.
NoteOceanBase Database also supports domain names as addresses. For example, |
| port | Specifies the port number of the remote database. If the remote database is an OceanBase Database, the port number can be that of the Proxy or an OBServer node in the cluster. If the port number is specified as that of an OBServer node, the network between the local database and the specified OBServer node must be accessible. If the remote database is an Oracle database, the IP address is that of the Oracle instance. |
| oracle_sid | The sid of the remote Oracle database. This parameter is required only when the remote database is an Oracle database. |
| cluster_name | The name of the remote OceanBase cluster. This parameter is required only when the IP address and port number are those of the Proxy, and the Proxy is deployed via ConfigUrl. The cluster name must be enclosed in double quotes. |
| local_cluster_name | The name of the local OceanBase cluster. This parameter is required only when the IP address and port number are those of the Proxy, and the Proxy is deployed via ConfigUrl. The cluster name must be enclosed in double quotes. |
| local_user | The username of the local database. |
| local_tenant | The tenant name of the local database. |
| local_password | The login password for the username of the local database. If the password contains special characters other than digits and letters (~!@#%^&*_-+=|(){}[]:;,.?/), double quotes must be used to enclose the password to avoid syntax errors. |
| local_ip | The IP address of an OBServer node in the local database cluster. |
| local_port | The port number of an OBServer node in the local database cluster. |
Examples
Example 1: Create a dblink named ob_dblink_proxy to connect to a remote OceanBase Database. The tenant name is the default oracle. The Proxy is deployed via ConfigUrl. The cluster name must be enclosed in double quotes to prevent the cluster name from being capitalized.
obclient> CREATE DATABASE LINK ob_dblink_proxy CONNECT TO ob_testuser@oracle IDENTIFIED BY **1** OB HOST '10.XXX.XXX.XXX:30084' CLUSTER "ob***";
Query OK, 1 row affected
Example 2: Create a dblink named ob_dblink_reverse_link to connect to a remote OceanBase Database with a reverse link. The tenant name is oracle.
obclient> CREATE DATABASE LINK ob_dblink_reverse_link CONNECT TO ob_testuser2@oracle IDENTIFIED BY **1** OB HOST '10.XXX.XXX.XXX:35305' MY_NAME local_ob_testuser@oracle identified by **2** host '10.XXX.XXX.XXX:35307';
Query OK, 1 row affected
Example 3: Create a dblink named orcl_dblink to connect to a remote Oracle database. The tenant name is oracle.
obclient> CREATE DATABASE LINK orcl_dblink CONNECT TO orcl_testuser@oracle IDENTIFIED BY **1** OCI HOST '10.XXX.XXX.XXX:1521/ORCL';
Query OK, 1 row affected