The Primary function of the redo log is to record all changes made to data.

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 their ...

sujeshm

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• Feb 27th, 2006

Redo log is a part of physical structure of oracle. its basic function is to record all the changesmade to daatabase information. wheneveer an abnormal shutdown take place preventing system to update the database, changes can be obtained from redolog and hence the changes are not lost.

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

satyam_Ora

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• 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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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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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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A materialized view is a replica of a target master from a singlepoint in time. The concept was first introduced with Oracle7 termed asSNAPSHOT. In Oracle release 7.1.6 snapshots were enhanced to enableDMLs along with a new terminology, updatable snapshots. With Oracle8.1.6 snapshots started to be used in data warehouse environments so anew terminology materialized view was introduced to address bothdistributed...

irfanyell

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• Apr 24th, 2008

Both are mirror copy of tables but in that main difference is in snapshot we cannot edit the data. in the case of materialized view we can edit the data.

pravin Karde

• Sep 25th, 2006

sir  i m a M.E. student & i developed a project on Materialized view selection & maintenance.sir for this i urgently need the architecture of Materialized view & its operation. sir pl. help me & send me if  possible.thanks waiting +vely.

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Public database link is created for the special user group PUBLIC. A public database link can be used when any user in the associated database specifies a global object name in a SQL statement or object definition.

edeed

 Profile Answers by edeed Questions by edeed

• Mar 27th, 2008

A database link is a pointer that defines a one-way communication path from an Oracle Database server to another database server. The link pointer is actually defined as an entry in a data dictionary ...

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Data Segment, Index Segment, Rollback Segment and Temporary Segment.

taraldesai

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• Jan 28th, 2008

Data, index , rollback, undo,cluster

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Each Index has an Index segment that stores all of its data.

taraldesai

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• Jan 28th, 2008

It's an oracle object as other object like table. It stores index key + rowid for that key. So when you scan index it finds respective rowid and fetch data from that rowid. and it's faster

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A Database contains one or more Rollback Segments to temporarily store "undo" information.

taraldesai

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• Jan 28th, 2008

It stores your uncommited temporart data. ex. If you do any insert/update/delete and you won't commit it is written in rollback segment.

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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

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• 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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No.

Tauseef

• Nov 25th, 2007

Yes. you can add integrity constraint. but that will effects the new records only not the existing one

Samuel Kiarie

• Mar 31st, 2006

Yes.Use Enable Novalidate to enforce the constraints. Existing data will not be checked, only new/update will be validated.

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Indexes are automatically maintained and used by ORACLE. Changes to table data are automatically incorporated into all relevant indexes.

C.Ramesh

• Oct 18th, 2007

Index is a Database object . It can be accessed rows physical fast. when you move the table from different table spaces or same table spaces indexes will unusually status. So You compulsory rebuild the index. Rebuilding the index is very fast than drop and create the new indexes.

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When an instance of an ORACLE database is started, its control file is used to identify the database and redo log files that must be opened for database operation to proceed. It is also used in database recovery.

Mohammed Abdul Afroze

• Oct 16th, 2007

Uses of a Controlfile:1.It is used to identify the names and locations of datafiles,redologfiles.2.Redo History is recorded during log switches.3.Checkpoint information is recorded at ckpts are m...

Lalit Vasuja

• Jan 4th, 2006

Control file contain the physical structure of database.it also contain the current log sequence number.when database mount ->open then oracle server check the consistency of the database through the control fie.

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An integrity constraint is a declarative way to define a business rule for a column of a table.

simakas

• Oct 5th, 2007

Special requirements for table data:1) allow NULL value2) uniqueness of value3) primary key4) foreign key5) special value size/text/length etc requirementsAll information is stored in Data Dictionary.

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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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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

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• 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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A database is divided into Logical Storage Unit called tablespaces. A tablespace is used to grouped related logical structures together.

Mohammed Abdul Afroze

• Sep 20th, 2007

It is a Logical area of storage in a Database, that directly corresponds to one or more physical files.

sandeep vig

• Oct 13th, 2005

A tablespace is a group of segments and a segment is a group of extents and an extent is a group of blocks.a tablespace can occupy two physical datafiles.

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Every ORACLE database contains a tablespace named SYSTEM, which is automatically created when the database is created. The SYSTEM tablespace always contains the data dictionary tables for the entire database.

Mohammed Abdul Afroze

• Sep 20th, 2007

Every Oracle Database contains a tablespace called system tablespace.This tablespace gets created at the time of database creation and it holds data dictionary information for the entire database.

Praveen

• Sep 15th, 2006

HelloAs far as i know, a system tablespace is the only tablespace which is created automatically, when the oracle DB is installed, no matter what the DB will contain atleast one tablespace and that  is the system tablespace. Do let me know if u have any other answers.Praveen.R

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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 condition must be a Boolean expression evaluated using the values in the row being inserted or updated and can't contain sub queries, sequence, the SYSDATE,UID,USER or USERENV SQL functions, or the pseudo columns LEVEL or ROWNUM.

fancyoracle

 Profile Answers by fancyoracle Questions by fancyoracle

• Aug 16th, 2007

A check constraint allows you to specify a condition on each row in a table. Note: A check constraint can NOT be defined on a VIEW. The check constraint defined on a table must refer to only columns i...

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