DBCA 删除RAC数据库实例
适用于使用DBCA安装RAC数据库过程中，中间节点断开的现象。
在我使用DBCA安装RAC数据库时，在90%时，rac1节点死机，故只能使用DBCA删除后再重建。
官方文档参考：
http://docs.oracle.com/cd/B19306_01/install.102/b14205/dbcacrea.htm#RISOL2405
6.7 Deleting an Oracle Real Application Clusters Database with DBCA
This section explains how to delete a RAC database with the DBCA. This process deletes a database and removes a database's initialization parameter files, instances, OFA structure, and Oracle network configuration. However, this process does not remove datafiles if you placed the files on raw devices or on raw partitions.
To delete a database with the DBCA:
1. Start the DBCA on one of the nodes:
The DBCA Welcome page appears.
2. Select Oracle Real Application Clusters and click Next.
After you click Next, the DBCA displays the Operations page.
3. Select Delete a database, click Next, and the DBCA displays the List of Cluster Databases page.
4. If your user ID and password are not operating-system authenticated, then the List of Cluster Databases page displays the user name and password fields. If these fields appear, then enter a user ID and password that has SYSDBA privileges.
5. Select the database to delete and click Finish.
After you click Finish, the DBCA displays a dialog to confirm the database and instances that the DBCA is going to delete.
6. Click Yes to begin the deletion of the database and its associated files, services, and environment settings, or click Cancel to stop the operation.
When you click OK, the DBCA continues the operation and deletes all of the associated instances for this database. The DBCA also removes the parameter files, password files, and oratab entries.
At this point, you have accomplished the following:
· Deleted the selected database from the cluster
· Deleted high availability services that were assigned to the database
· Deleted the Oracle Net configuration for the database
· Deleted the OFA directory structure from the cluster
· Deleted the datafiles if the datafiles were not on raw devices