dhussainpathan

• Apr 9th, 2007

The Redo log files records the changes made  to the database in the form of REDOLOG entries, which are helpful at the time of Database Recovery Process.

rajesh chadalawada

• Dec 2nd, 2006

     Redo Log is ment to trce or note  the modifications that are applied to data buffer cache it will note on folloing situations1)for every 3 seconds2)when redo log buffer reaches to 1MB3)before db_cache writes data to datafiles4)when ever commited

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Deepa Kale

• Apr 11th, 2007

If user authentication is managed by the database, security administrators should develop a password security policy to maintain database access security. For example, database users should be require...

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Sandesh

• Jun 6th, 2007

Change the domain name in the sqlnet.ora file in NAMES.DEFAULT_DOMAIN parameter.

Bhavani Shekhar

• Mar 15th, 2006

The Question is not clear about Where the Oracle database is residing.If the Oracle Database is resides on ur local machine then the domain name must be updated in the tnsnames.ora file. change this f...

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Taj_N

• Jul 16th, 2007

An Index is based on tree structre that allow direct access to a row in a table, oracle uses different type of index 1) B-Tree Index2) Bitmap Index

srujana

• Aug 23rd, 2005

It is created in existing table to locate rows more quickly&efficiently. the users cannot see the indexes,they are just used to speed up the queries

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 Multiple   instances   accessing  the  same  database  (Only  In  Multi-CPU environments) 

satyam_Ora

 Profile Answers by satyam_Ora Questions by satyam_Ora

• Aug 18th, 2007

Very true---Multiple instances uses by single database files is called parallel server. in this condition database files act as a server and connected with differenet instances.But each instances can use database files in same time.So the database file is called Parallel server.

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An  index  is a database structure used by the server to have direct access of a row in a table. An  index  is automatically created when a unique of primary key constraint clause is specified in create table comman (Ver 7.0)

satyam_Ora

 Profile Answers by satyam_Ora Questions by satyam_Ora

• Aug 18th, 2007

Indexes are used both to improve performence and to ensure uniquness of a column. Oracle automatically creates an index when a UNIQUE or PRIMARY key constarints clause is specified in a create table command.We can manually create our own indexes via the create index command.

satyam_Ora

 Profile Answers by satyam_Ora Questions by satyam_Ora

• Aug 18th, 2007

An index is a database structure used by the server to quickly find a row in a table.In a relational database the physical location of row is irrelevent-unless, of course, the database needs to find i...

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 A  database  instance  (Server) is a set of memory structure and background processes that access a set of database files. The process can be shared by all users. The  memory  structure  that  are  used  to  store  most  queried data from database.  This  helps up to improve database performance by decreasing the...

ranjanam

• Aug 26th, 2007

Database instance(server) is the combination of memory structure and background process. It's a way to connect to the oracle database.

satyam_Ora

 Profile Answers by satyam_Ora Questions by satyam_Ora

• Aug 18th, 2007

A database instance also know as server is a set of memory structures and background processes that access a set of database files.It is possible for a single database to be accessed by multiple insta...

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senthilora

 Profile Answers by senthilora Questions by senthilora

• Sep 24th, 2007

ORA-1555 error can occur in Oracle 10g also even with UNDO RETENTION GUARANTEE enabled. ORA-1555 happens, when Oracle server process could not find the block-image in UNDO tablespace for the read...

paparao

• Oct 23rd, 2006

This shanshot too old. -> problem occurs generally in 9i only.  Whether in 10g, at the time of tablespace creation, retuntion guarentee is applied it automatically we can supress( by default i...

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senthilora

 Profile Answers by senthilora Questions by senthilora

• Sep 24th, 2007

Another suggestion could be: Find the Master Table(s) of the given table and export / import them all.

balakrishna

• May 28th, 2006

If u want to import the table just say constraints=n the movement table got imported then u create constriant on that tables.

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senthilora

 Profile Answers by senthilora Questions by senthilora

• Sep 24th, 2007

And.. It does not store any data value in it unlike normal index do.Queries will not get benefitted. This can be used only for analysis.

Varun

• Sep 11th, 2005

1. These are permanent and continue to exist unless we drop them.2. Their creation will not affect existing and new sessions. Only sessions marked for Virtual Index usage will become aware of their ex...

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senthilora

 Profile Answers by senthilora Questions by senthilora

• Sep 24th, 2007

1. set SHARED_SERVERS=(more than 1) in init.ora2. make changes in tnsnames.ora file to get the connection with DISPATHERS rather than dedicated servers

SALIH

• Dec 15th, 2005

Use DBCA toolYou will get the option to select shared server mode.

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senthilora

• Sep 24th, 2007

There are many ways to do that.? Following is the one of the ways I would prefer as I do it usually.You can achieve this by having a small Unix Scripting / Windows Shell Scripting?/ any other script...

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senthilora

• Sep 24th, 2007

And.. I think, the question is about Data Migration - something related to migrating data between different databases.I have done using different tools like Data Junction, Informatica, even PL/SQL and SQL Loader.

Jacob Asirwadam SK, Biguvu

• May 21st, 2007

RAC stands for Real Application Cluster. In previous versions, it is known as PARALLEL SERVER. RAC is a mechanism that allows multiple instances (on different hosts/nodes) to access the same database....

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Mohammed Abdul Afroze

• Sep 28th, 2007

An Extent is a set of contignous data blocks obtain in a single allocation and used to store specific type of information.

Yoh

• Jul 30th, 2006

Extends are a collection of data blocks

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 Group  of  tables  physically  stored  together  because  they share common columns and are often used together is called Cluster.

parthokonar1

 Profile Answers by parthokonar1 Questions by parthokonar1

• Sep 28th, 2007

Yes that is true, For creating cluster we first create the cluster via index/hash, then we all the tables in the cluster.

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Whenever commit,checkpoint or redolog buffer is 1/3rd full

Jayesh Patel

• Oct 9th, 2007

LGWR writes:1) COMMIT/ ROLLBACK2) 1 MB of large transaction3) Before DBWR writes4) 1/3 of REDO LOG is full5) time out occurs6) Check Point encounters

SALIH

• Dec 15th, 2005

1.COMMIT or ROLLABCK2.time out occurs (3 secs)3 1/3 of log is full4. 1 mb of redo5. Checkpoint occurs

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Ajwat Hasan

• Oct 10th, 2007

Often the word "lock" is synonymous to enqueue. In this document, "enqueue" will be used for the locking mechanism that you can find in V$LOCK. "locking" will be used whe...

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The primary functional difference between logical and physical standby database setups is that logical standby permits you to add additional objects (tables, indexes, etc) to the database, while physical standby is always an exact structural duplicate of the master database. The downside, though, is that logical standby is based on newer technologies (logical standby is new in Oracle 9.2) and tends...

Ashu Shukla

• Oct 29th, 2007

A physical or logical standby database is a database replica created from a backup of a primary database. A physical standby database is physically identical to the primary database on a block-fo...

santhosh

• Jun 26th, 2006

Physical Standby - acheived by copying the archivle log filesLogical Standby - makes the dml statements using archivelogs generated and applies to the secondary database

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Enqueues are another type of locking mechanism used in Oracle. An enqueue is a more sophisticated mechanism which permits several concurrent processes to have varying degree of sharing of "known" resources. Any object which can be concurrently used, can be protected with enqueues. A good example is of locks on tables. We allow varying levels of sharing on tables e.g. two processes can lock a table...

manoj seemar

• Nov 2nd, 2007

An enqueue is a sophisticated locking mechanism that permits several concurrent processes to share known resources to varying degrees. Any object that can be used concurrently can be protected with en...

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Latches are low level serialization mechanisms used to protect shared data structures in the SGA. The implementation of latches is operating system dependent, particularly in regard to whether a process will wait for a latch and for how long.A latch is a type of a lock that can be very quickly acquired and freed. Latches are typically used to prevent more than one process from executing the same piece...

manoj seemar

• Nov 2nd, 2007

Latches are simple, low-level serialization mechanisms to protect shared data structures in the system global area (SGA). For example, latches protect the list of users currently accessing the databas...

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