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What is an Integrity Constrains ?
An integrity constraint is a declarative way to define a business rule for a column of a table.
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What is the use of Control File ?
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.
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How are Indexes Update ?
Indexes are automatically maintained and used by ORACLE. Changes to table data are automatically incorporated into all relevant indexes.
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Describe Referential Integrity ?
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
- 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
- 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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What is Rollback Segment ?
A Database contains one or more Rollback Segments to temporarily store "undo" information.
taraldesai
- 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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What is an Index Segment ?
Each Index has an Index segment that stores all of its data.
taraldesai
- 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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What are the different type of Segments ?
Data Segment, Index Segment, Rollback Segment and Temporary Segment.
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What is Public Database Link ?
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
- 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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What is the differnece between materialized view and snapshot
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
- 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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What is meant by snapshot error? expain it.
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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What are the Large object types supported by Oracle?
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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What is a Redo Log ?
The set of Redo Log files for a database is collectively known as the database's redo log.
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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What is the function of Redo Log ?
The Primary function of the redo log is to record all changes made to data.
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
- 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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Database Connectivity Error
Here i'm sending all of you the error which occurred frequently during database connection.While creating a data block in Oracle Forms, the error which encountered frequently is "ORA-12560: TNS Protocol Adapter Error" During lectures instructor had told us that if such error encountered then copy the TNSNAMES.ORA file from ..oracleora92networkadminsample to forms9inetworkadminsample as it contains...
sahil4439
- Jun 15th, 2008
dude ur databse is not running...right click on my compiuter>manage>services& applictaions(on right side)>services>oracle_databse_name(the datasbe that ur trying ...
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Remote and Local user
what is remote login user and local user in database?And sid is used when user want to login as local user and Glodal database name is used when user wants to login as remote user..What does it mean ?
cmanan
- Jul 10th, 2008
When you have distributed environment,you may access one database from other.This is normally done via db link.So lets say you have flight database and customer dabatabase.Now from customer data...
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Explain the relationship among Database, Tablespace and Data file.
Each databases logically divided into one or more tablespaces one or more data files are explicitly created for each tablespace.
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
- 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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What are advantage of Data Dictionary manage Tablespace
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
- 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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What is the maximum number of CHECK constraints that can be defined on a column ?
No Limit.
jjvetri
- Aug 5th, 2009
You can create any number of check constraintsseparated by AND, OR, or NOT to create more complex conditions.
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PMON Process
From where does PMON gets the informance about failure? How is the user process terminited?
premk
- Dec 23rd, 2009
When user process is terminated abruptly due to power cut or any other factors then oracle database instance goes down then PMON mandatory background process is activated i.e it will then writes the c...
aabishkar
- Sep 28th, 2009
When a user process fails or when it is killed, it then cleans up the cache and frees resources that the process used. PMON checks server processes and restarts them if they have failed.
Oracle Architecture Interview Questions
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