ORACLE Interview Questions and Answers
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(Continued from previous part...)
470. What is Fine Grained Auditing? (for DBA
Fine Grained Auditing (DBMS_FGA) allows auditing records to be generated when certain rows are selected from a table. A list of defined policies can be obtained from DBA_AUDIT_POLICIES. Audit records are stored in DBA_FGA_AUDIT_TRAIL. Look at this example:
o Add policy on table with autiting condition...
execute dbms_fga.add_policy('HR', 'EMP', 'policy1', 'deptno > 10');
o Must ANALYZE, this feature works with CBO (Cost Based Optimizer)
analyze table EMP compute statistics;
select * from EMP where c1 = 11; -- Will trigger auditing
select * from EMP where c1 = 09; -- No auditing
o Now we can see the statments that triggered the auditing condition...
select sqltext from sys.fga_log$;
delete from sys.fga_log$;
471. What is a package ? What are the advantages of packages ?
What is Pragma EXECPTION_INIT ? Explain the usage ?
The PRAGMA EXECPTION_INIT tells the complier to associate an exception with an oracle error. To get an error message of a specific oracle error.
e.g. PRAGMA EXCEPTION_INIT (exception name, oracle error number)
472. What is Fine Grained Access Control? (for DBA
See question "What is a Virtual Private Database".
473. What is a Virtual Private Database? (for DBA
Oracle 8i introduced the notion of a Virtual Private Database (VPD). A VPD offers Fine-Grained Access Control (FGAC) for secure separation of data. This ensures that users only have access to data that pertains to them. Using this option, one could even store multiple companies' data within the same schema, without them knowing about it.
VPD configuration is done via the DBMS_RLS (Row Level Security) package. Select from SYS.V$VPD_POLICY to see existing VPD configuration.
474. What is Raise_application_error ?
Raise_application_error is a procedure of package DBMS_STANDARD which allows to issue an user_defined error messages from stored sub-program or database
trigger.
475. What is Oracle Label Security? (for DBA
Oracle Label Security (formerly called Trusted Oracle MLS RDBMS) uses the VPD (Virtual Private Database) feature of Oracle8i to implement row level security. Access to rows are restricted according to a user's security sensitivity tag or label. Oracle Label Security is configured, controlled and managed from the Policy Manager, an Enterprise Manager-based GUI utility.
476. Give the structure of the procedure ?
PROCEDURE name (parameter list.....)
is
local variable declarations
BEGIN
Executable statements.
Exception.
exception handlers
end;
477. What is OEM (Oracle Enterprise Manager)? (for DBA
OEM is a set of systems management tools provided by Oracle Corporation for managing the Oracle environment. It provides tools to monitor the Oracle environment and automate tasks (both one-time and repetitive in nature) to take database administration a step closer to "Lights Out" management.
478. Question What is PL/SQL ?
PL/SQL is a procedural language that has both interactive SQL and procedural programming language constructs such as iteration, conditional branching.
479. What are the components of OEM? (for DBA
Oracle Enterprise Manager (OEM) has the following components:
. Management Server (OMS): Middle tier server that handles communication with the intelligent agents. The OEM Console connects to the management server to monitor and configure the Oracle enterprise.
. Console: This is a graphical interface from where one can schedule jobs, events, and monitor the database. The console can be opened from a Windows workstation, Unix XTerm (oemapp command) or Web browser session (oem_webstage).
. Intelligent Agent (OIA): The OIA runs on the target database and takes care of the execution of jobs and events scheduled through the Console.
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