Rollback Segments are used :To generate read-consistent database information during database recovery to rollback uncommitted transactions for users.

Mohammed Abdul Afroze

• Sep 18th, 2007

Rollback Segment Stores Undo Information and are used for the following purposes.1. To undo the previous command2. For read consistency and3. For crash recovery.

vijay

• Jun 15th, 2007

Transaction rollback:  Suppose if you  are updating the data, now you want to rollback so the old image will read from rollback segments.  You are old image from rollback segment.Transa...

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The set of Redo Log files for a database is collectively known as the database's redo log.

satyam_Ora

 Profile Answers by satyam_Ora Questions by satyam_Ora

• May 21st, 2008

Oracle maintains logs of all transactions against the databse. These transactions are recorded in files called Online Redo log files.These logs are used to recover the database's transaction in th...

sampath kumar

• May 17th, 2006

Red log file store the changes in the data file.it mainly used for recovery purpose..

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A Control file records the physical structure of the database. It contains the following information.Database NameNames and locations of a database's files and redolog files.Time stamp of database creation.

Mohammed Abdul Afroze

• Sep 20th, 2007

The controlfile contains :1. Name and Location of Datafiles, Redo Logfiles.2. Timestamp of Database Creation.3. Current log sequence number is recorded when log switches are occur.4. Checkpoint inform...

nagabhushan reddy

 Profile Answers by nagabhushan reddy Questions by nagabhushan reddy

• Mar 7th, 2006

control file is a binary filewhich having information 1.database name2.database creation3.checkpoint information4.no of datafiles5.redolog files

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raghu2110

 Profile Answers by raghu2110 Questions by raghu2110

• May 20th, 2008

Blob datatype is used for storing large Binary data Like Photos,signatures etc Clob datatype is used for stoeing large character data upto 4GB like resume and other docs

manish hoiyani

• Sep 14th, 2006

Clob, blob, used to unstructured data and binary data respectively.

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The data dictionary of an ORACLE database is a set of tables and views that are used as a read-only reference about the database.It stores information about both the logical and physical structure of the database, the valid users of an ORACLE database, integrity constraints defined for tables in the database and space allocated for a schema object and how much of it is being used.

Sudhakar

• Sep 27th, 2007

Data Dictionary is a read-only set of tables that provides information about the database. in order to avoid the I/O cost, these data dictionary views are used

Mohammed Abdul Afroze

• Mar 25th, 2007

Answer.  Oracle continously requests and update the information in the data dictionary of the database.To minimize the performance of the system internal operation,data dictionary cache holds the dictionary information.

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ORACLE database's data is stored in data blocks. One data block corresponds to a specific number of bytes of physical database space on disk.

matabrez

 Profile Answers by matabrez Questions by matabrez

• Jan 10th, 2011

Smallest logical of Oracle database. In Oracle 10g default data block size is 8192 byres means 8k.
Other data block size are 2k, 4k, 8k, 16k, 32kWe have only these available data blocks in oracle database.

C.Ramesh

• Oct 27th, 2007

Oracle Data Blocks is logical storage unit of Oracle and One Oracle Data Blocks containts multiple of Operating system Blocks. Data blocks contains contigous of Bytes.

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Where does the process dumps information about the error?

ARUN BHUKKER

 Profile Answers by ARUN BHUKKER Questions by ARUN BHUKKER

• Oct 19th, 2012

Errors are stored in alert.log file it can be shecked using the parameter background_dump_dest

Use show parameter background_dump_dest
for path of the alert.log in trace directory

matabrez

 Profile Answers by matabrez Questions by matabrez

• Jan 10th, 2011

Alerts will log to alert.log  and alert trace files will be saved in  $ORACLE_HOME/admin/bdump directory.

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Souravi

• Jun 6th, 2018

No , new columns cannoot be added in view. The view is just a select query so it should be dropped and recreated for any such requirement.

patelmosin

• Jan 18th, 2018

Yes

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What are the advantages & disadvantages of both two.

Harshad Khuspe

• Dec 27th, 2015

In case of RAC (Real Application Cluster) use of GNS will be helpful if we have more than 10 node cluster. GNS need not to be assign IP addresses and it select automatically with the help of DHCP

frankie Lester

• Aug 11th, 2015

GNS uses DNS and DHCP to assign IP address on the network.

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The Information in a redo log file is used only to recover the database from a system or media failure prevents database data from being written to a database's data files.

Dinesh Chandra

• Aug 27th, 2012

Redo log records the changes made in database. Redo logs is mainly used to recover data.

rohitmisri

 Profile Answers by rohitmisri Questions by rohitmisri

• Jun 17th, 2010

Hi,Redo log information is the one of the major pard of the database , at any time if the oracle server instance get aborted and then it need recovery, so at that time redo log plays a role to recover...

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A rule defined on a column (or set of columns) in one table that allows the insert or update of a row only if the value for the column or set of columns (the dependent value) matches a value in a column of a related table (the referenced value). It also specifies the type of data manipulation allowed on referenced data and the action to be performed on dependent data as a result of any action on referenced...

ddf_dba

 Profile Answers by ddf_dba Questions by ddf_dba

• Dec 21st, 2007

Referential integrity is a relationship between two tables, one being the 'parent' and the other being the 'child'.  The 'child' table references values in the 'parent...

sivamurugan9182

 Profile Answers by sivamurugan9182 Questions by sivamurugan9182

• Dec 14th, 2007

Sorry i not here to give the answer.But i just want to mention as i was a beginner in the learning of OracleDB,i was quite confused of the answers given by the beloved forum members(not all)...

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Each databases logically divided into one or more tablespaces one or more data files are explicitly created for each tablespace.

swetashashi

 Profile Answers by swetashashi Questions by swetashashi

• Apr 16th, 2009

Databases, tablespaces, and datafiles are closely related, but they have important differences:1) An Oracle database consists of at least two logical storage units called tablespaces, which collective...

swetashashi

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• Apr 16th, 2009

Each databases logically consists of one or moretablespaces One or more data files are explicitly createdfor each tablespace.

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A schema is collection of database objects of a User.

ARUN BHUKKER

 Profile Answers by ARUN BHUKKER Questions by ARUN BHUKKER

• Oct 19th, 2012

A schema is the set of objects (tables, views, indexes, etc) that belongs to an user account. It is often used as another way to refer to an Oracle account. Most Oracle database installations traditio...

Mohammad Mujeeb

• Oct 25th, 2011

Schema is a collect of object (table,view,cluster etc) that belongs to an user account.

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Each Non-clustered table has a data segment. All of the table's data is stored in the extents of its data segment. Each cluster has a data segment. The data of every table in the cluster is stored in the cluster's data segment.

Harshad Khuspe

• Dec 27th, 2015

Tablespace is made up of Segment. Segment is made up of extents and extents are made up of contiguous oracle blocks. Segments are nothing but a table. i.e. Table Emp is nothing but segment emp. You can check things from data dictionary view DBA_Segments.

pradeep

• May 5th, 2015

A data segment is a set of extents allocated to a certain logical structures

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SID (System Identifier)  :  A SID (almost) uniquely identifies an instance.  Actually, $ORACLE_HOME, $ORACLE_SID and $HOSTNAME identify an instance uniquely. The SID is 64 characters, or less; at least on Oracle 9i. The system identifier is included in the CONNECT_DATA parts of the connect descriptors in a tnsnames.ora file. The SID defaults to the database name. Global Database Name...

pavan

• Jul 4th, 2017

Can a database name can be same across multiple instances, and can the instances number be same? If yes what is SID in that case?

shaikhannan

 Profile Answers by shaikhannan Questions by shaikhannan

• Feb 3rd, 2010

SID = identifies the database instance (database name + instance number). So if your database name is somedb and your instance number is 3, then your SID is somedb3. DB Name = Name of the database (d...

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mmaz2002

 Profile Answers by mmaz2002 Questions by mmaz2002

• Jul 15th, 2009

All Extent info is maintained in Dictionary which is infact a dis-advantage, Also in case of a huge insert operation undo is generated.

deep chandan

 Profile Answers by deep chandan Questions by deep chandan

• Dec 30th, 2008

The main advantage of using dictionary managed tablespaces is that in this we can give the size of the extents according to our need. We can modify extent size but in locally managed tablespace extents are of uniform size.

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Sarkar

• Mar 29th, 2016

I want to know about wrap background logic.

akebono

 Profile Answers by akebono Questions by akebono

• Jan 30th, 2009

DBMS_OBFUSCATION_TOOLKIT package is  a simple API for data encryption

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How will you identify database size when you create a database first time?

Caesar Dutta

• Nov 6th, 2017

Select sum(bytes) from dba_segments

SURAJ BANSODE

• Oct 14th, 2016

To find the size of database we need to Sum (datafiles+redo log files+temp files+control files)

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A database link is a named object that describes a "path" from one database to another.

Vinod Karuturi

• Nov 16th, 2015

A database link is a schema object in one database that enables you to access objects on another database. The other database need not be an Oracle Database system. However, to access non-Oracle systems you must use Oracle Heterogeneous Services.

Madhu Alampalli

• Sep 24th, 2015

Cluster key is a related column of tables in the cluster. For example, in Table EMP which has (EMP NO, EMP NAME, DEP NO, etc ) and DEPT which has (DEPT NAME, DEPT NO etc), DEPT NO is the cluster key in this cluster.

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sanjayoracle

 Profile Answers by sanjayoracle Questions by sanjayoracle

• Apr 25th, 2008

Just in simple words.....Ora01555 error occurs when a transation fails when it cannot able to find read consistence image in rollback segment. To solve this problem: Increse the Undo_RetentionCheers :)

Mohammed Abdul Afroze

• Mar 25th, 2007

Answer: Avoiding Snap Shot too old error-(oerr ora 01555).   First thing here we understood how is the rbs works.This will work in circular fashion by looping around the reuse of the ex...

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