Securing Your Logical Standby Database

A logical standby mines the primary database redo and reconstructs the higher level SQL operations that resulted in the database change, and then applies these SQL statements to maintain the standby database. The benefits to using a logical standby is that

• It can be open for reads
• Can support indexes and materialized views
• Can add tables, schemas and have read-write access to these tables and schemas (as long as they are not managed by redo apply)
• Perform rolling upgrades, for example the primary may be using 10g and the logical standby could be using 11g
• Idea for testing patch sets
• Idea as a staging system to propagate changes

The logical standby database is in Read-Write mode means a fully updatable mode. A database can be accessed and potential data may be changed. So Oracle data guard provides a lock. We can configure GUARD on the database at a different level according to our requirement.

A user access can be controlled with GUARD.

We can enable GUARD with ALTER DATABASE GUARD [ALL | STANDBY | NONE] command.

There are three level for GUARD.

ALL: We can use ALTER DATABASE GUARD ALL  statement. It prevents users from making changes to any data in the database.

STANDBY: It Prevents users from making changes to any data maintained by Data Guard SQL Apply

NONE: If we provide Guard none then it provides normal security a user which have access to objects can change data in that.

To check Guard_status use following query.

SQL> select guard_status from v$database;

GUARD_STATUS

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STANDBY

Note: You can set your value based on requirement.