Create a database link from PolarDB-O to PolarDB-O

For more information about how to create a database link from a PolarDB-O cluster to a user-created Oracle database hosted on an Elastic Compute Service (ECS) instance, see Create a database link from PolarDB-O to Oracle.

Prerequisites

• The source database and the destination database belong to the same Alibaba Cloud account.
• The source database and the destination database are in the same region.
• The kernel version of the PolarDB-O cluster is the latest kernel version. For information about how to upgrade the kernel version, see Upgrade the minor version.

Notes

You can create a maximum of 10 database links for each PolarDB-O cluster. Each database link consumes one database link quota of both the source cluster and the destination cluster.

Procedure

1. Log on to the PolarDB console.
2. In the upper-left corner of the console, select the region where the cluster resides.
3. Find the cluster, and then click the cluster ID.
4. In the left-side navigation pane, choose Settings and Management > Databases.
5. On the Databases page, click the DBLinks tab in the upper part.
6. Click Create DBLink and configure the following parameters.

   Parameter	Description
   DBLink Name	You can enter a custom name of the database link. The name must meet the following requirements: The name must contain lowercase letters and can contain digits and underscores (_). It must start with a lowercase letter and end with a letter or a digit. It must be 1 to 64 characters in length. This name is required when you use the database link for cross-database queries.
   Source Instance Name	The name of the current PolarDB-O cluster is used as the fixed value. You cannot modify this parameter.
   Source Database Name	Select a database in the current PolarDB-O cluster from the drop-down list.
   Destination Instance	Select a destination cluster for the database link from the drop-down list. Note You can only select a cluster deployed in the same region as the source cluster.
   Destination Account	The account that is used to access the destination cluster. For more information about how to create an account, see Create database accounts.
   Destination Account Password	The password of the account that is used to access the destination cluster.
   Destination Database Name	Enter the database name of the destination cluster. For more information about how to create a database, see Databases.

7. Click OK.

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