Real time Oracle Interview Questions

we can find corrupted block by this command in sql>select * from database_block_corruption;

we can also find the corrupted block from unix command by database verify $ dbv file=path block size=8192;

Block corruption can be viewed from the view v$database_block_corruption there is no view like v$block_corruption.Using RMAN backup – block media recovery (oracle 10g database)i.) Select * from ...

Please check archive log destination has enough space, 100% full archivelog destination makes database hanged.

First check the Alert log file if any error related to hang issue such. Then I would like to suggest one important step, that is please check archive log destination whether it has enough space, some ...

By using the command

crontab

Using crontab we can schedule task/jobs to run at particular time, date, day basis. steps. 1. Login to unix 2. At $prompt 'crontab -l' use this command to check what jobs are already schedule...

you just validate it.. by using validate procedure and validate package commands.. ok don't worry

we can use the  @?/rdbms/admin/utlrp.sql

The below listed are the scripts that were executed to valid the DBMS_STAT on particular databses.

@?/rdbms/admin/dbmsstat.sql

@?/rdbms/admin/prvtstas.plb

@?/rdbms/admin/prvtstat.plb

Schema B

By default in Schema A the table will be updated

Dual is a single row table in the system tablespace accessible to all the schema users. Selecting from the DUAL table is useful for computing a constant expression with the SELECT statement. Because D...

You can issue "sysdate" from any table, but the result will be as many rows as your table , that you used.

The whole idea behind using "DUAL" table is to meet the the criteria as defined by RDBMS , that you have to use "Select.. from" syntax to get the values from column.

First look into your character set by using this command:-
select * from v$nls_parameters;

There will be a character set column in it.
Copy it and
EXPORT NLS_LANG=(Paste it here before you start your import.)

I bet it'll work.

 In 10g exp/imp can be used to convert to character set but it can result in some data loss or data corruption.consier also when we are migrating form character set A to set B make sure to avod data loss that  B is a superset of A.

Usually, whenever MORE THAN 2 to 4 % of rows in a table are going to be returned by  a query, a full table scan is preferred over an indexed scan. So in this case, as 35% of rows of the table are accessed by the application, a full table scan will be used.

Hi,
15% of 100 million rows is still a lot of rows and would take lot of time if there is a full table scan.

yes you can use it ...but need to enable the index

we can disable index so that we can write query

Combo Box will be useful in this Scenario

The Combo Box is the best option for this cause it is only accept the user input when
compare with other list styles.

We need to Create the Package Specification before creating the Package Body

Create package specifications before creatin package body.

mutation of triggers is an example of deadlock.......for flashback we can use to being tables from recyclebin

V$SGA - Provided that the user is granted DBA access

Hi

I strongly feel, with OUI, installtion is more or less same on Windows and Unix.
there is nothing great about Unix installation.

krishna

1. installing oracle on Windows is piece of cake which requires less DBA intervention.2. While installing Oracle on Linux is a laborious process which involves ina. creating the groups (oinstall, orac...

Once you got inside the OUTER_LOOP, it comes out only after the NOTFOUND statement.

So OUTER_LOOP will be valuated first.Its similar to C language, first OUTER_LOOP will valuated followed by an INNER_LOOP.

inner layer. execution carry on furthur without going to outer exception blocks.

when we try access a  table which is locked or manipulated by another user

You are running a cartisian query, typically by mistake. Make sure every table has a join criteria specified for it.  You are working on a table with 100+million rows.  The databa...

The ANALYZE requires significant system resources, So it is always better to run the ANALYZE command during off peak hours.

You have to run the analyze command during off peak time only because it actually performs full table scan.

Entire Disk is corrupted???1) Production database runs on RAID Levels or on HUGE EMC Storage! 2) Changes are less for data loss on all disks - if it's on RAID! Yes - if there is a failure with Disk Co...

if the entire disk is corrupted and no backup is there don nothing sit and relax their is no possibility of recovery ...a backup is required for restoration and for recovery redo log and archive logs....

Database Modelling is  - Logical and Physical Modelling.  Logical Modelling is independent of Type of Database.. Once Logical Database Model is built.  You can create Phsical Model depe...

refer http://www.aisintl.com/case/library/R-Theory_vs_ER/r-theory_vs_er.html 
 
it says, database modeling comprises: discovery, design, documentation, communication, DDL generation, re engineering

Bulk sql are forall and bulk collect INTO statement,
For performence reason the bulk bind is used to eleminate the context switching between two sql and pl/sql eng.