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DataBase Administrator (DBA) Interview Questions and Answers

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214. What is Auditing?

Monitoring of user access to aid in the investigation of database use.


215. What are the responsibilities of a Database Administrator?

* Installing and upgrading the Oracle Server and application tools.
* Allocating system storage and planning future storage requirements for the database system.
* Managing primary database structures (tablespaces)
* Managing primary objects (table, views, indexes)
* Enrolling users and maintaining system security.
* Ensuring compliance with Oracle license agreement
* Controlling and monitoring user access to the database.
* Monitoring and optimizing the performance of the database.
* Planning for backup and recovery of database information.
* Maintain archived data on tape
* Backing up and restoring the database.
* Contacting Oracle Corporation for technical support.


216. What is a trace file and how is it created?

Each server and background process can write an associated trace file. When an internal error is detected by a process or user process, it dumps information about the error to its trace. This can be used for tuning the database.


217. What is a profile?

Each database user is assigned a Profile that specifies limitations on various system resources available to the user.


218. How will you enforce security using stored procedures?

Donít grant user access directly to tables within the application. Instead grant the ability to access the procedures that access the tables. When procedure executed it will execute the privilege of procedures owner. Users cannot access tables except via the procedure.


219. What are the dictionary tables used to monitor a database spaces?

DBA_FREE_SPACE DBA_SEGMENTS DBA_DATA_FILES.


220. What are the roles and user accounts created automatically with the database?

DBA - role Contains all database system privileges. SYS user account - The DBA role will be assigned to this account. All of the base tables and views for the databaseís dictionary are store in this schema and are manipulated only by ORACLE. SYSTEM user account - It has all the system privileges for the database and additional tables and views that display administrative information and internal tables and views used by oracle tools are created using this username.


221. What are the minimum parameters should exist in the parameter file (init.ora)?

DB NAME - Must set to a text string of no more than 8 characters and it will be stored inside the datafiles, redo log files and control files and control file while database creation. DB_DOMAIN - It is string that specifies the network domain where the database is created. The global database name is identified by setting these parameters (DB_NAME & DB_DOMAIN) CONTORL FILES - List of control filenames of the database. If name is not mentioned then default name will be used. DB_BLOCK_BUFFERS - To determine the no of buffers in the buffer cache in SGA. PROCESSES - To determine number of operating system processes that can be connected to ORACLE concurrently. The value should be 5 (background process) and additional 1 for each user. ROLLBACK_SEGMENTS - List of rollback segments an ORACLE instance acquires at database startup. Also optionally LICENSE_MAX_SESSIONS,LICENSE_SESSION_WARNING and LICENSE_MAX_USERS.


221. How can we specify the Archived log file name format and destination?

By setting the following values in init.ora file. LOG_ARCHIVE_FORMAT = arch %S/s/T/tarc (%S - Log sequence number and is zero left padded, %s - Log sequence number not padded. %T - Thread number left-zero- padded and %t - Thread number not padded). The file name created is arch 0001 are if %S is used. LOG_ARCHIVE_DEST = path.

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