To create a database link connection, the database link must be established by clicking the Create Database Link option from the context menu, after the relevant connection has been created in RED. Any existing connections can be used as a database link connection if:

  • the connection type is Database;
  • the Database Link Name field is populated with a name for the database link;
  • the Create Database Link option has been selected from the connection's right click context menu. A confirmation message is displayed when the database link has been created.

To create a new Database Link type connection you need to do the following:

  1. Enter a name for the new Connection.
  2. Set the Connection Type to Database.
  3. Select an ODBC Source (DSN) to extract the source data.
  4. Populate the Database ID field with a valid Oracle SID or TNS Name for Oracle Databases.
  5. Enter a Database Link Name for the database link. This is a required field for establishing the Database Link connection.
  6. Enter the Extract User ID and Extract User Password for the user that has access to the source database when not using Windows Authentication.
  7. Once a connection has been set up, you can right-click the connection name to see the following menu:
  8. Once the Create Database Link option is selected, RED attempts to create a user database link to the source database. If the link already exists, a prompt appears to confirm if you want to overwrite the existing link.

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A number of problems can occur during this action, and your database administrator should be consulted:

For SQL Server a trusted link will be created if the extract user in the connection is set to dbo. In all other cases the extract user/password will be used as the log on for the remote server.

For Oracle data warehouses the more common problems are:

  • Insufficient privileges to create the link. You need the Create Database Link privilege in order to create a new link.
  • TNS could not resolve the connection to the remote database. The database link uses the value entered in the SID field of the connection to identify the remote database. This value must be a valid entry in the Tnsnames table for the source database.


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