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Different types of table join.
dhampack
- Nov 24th, 2008
In Sybase(T-SQL), there are 3 types of joins1) Equi Join2) Natural Join3) Outer Join (left & right)Joins based on equality (=) are called equijoins. Equijoins compare the values in the columns bei...
Bobby
- Sep 14th, 2006
There are 3 types of joins basis on Oracle 8i Simple join ?????1. Equi join : Equi join is one which contains comparision operator '=' in where clause. ?????2. Non Equi join: If the com...
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How would you pass hints to the SQL processor?
dhampack
- Nov 24th, 2008
I would say, write more sql statementfor exin join statement if x=y, y=z (you can also add x=z to give more hint to optimizer)
LAKSHMAN CHOWDARY
- Oct 17th, 2005
USING COMMENT LINES WITH (+) SIGN YOU CAN PASS THE HINTS TO SQL ENGINE----------->/* +PARALLEL() */
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When normalizing a table that can have a many to many relationship with another table, what steps should you take?
Looking for a detailed answer if possible
aw_zahid
- Nov 18th, 2008
A many-to-many relationship is usually resolved by making a tertiary (third intermediate) table where PKs of both the related tables are recoreded as FKs.Example: A student can take many classes and a...
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How do you know that fragmentation is occurred and how do you fix it. ...?
subha gunasekaran
- Jun 5th, 2008
To see fragmentation:select sum(bytes)/1024 from dba_data_files where tablespace_name='';output: 10select sum(bytes)/1024 from dba_segments where tablespace_name='';ouput :...
sjpunshi
- Sep 25th, 2007
Query dba_segments, dba_free_space for the tablespace and table, if too many extents are avaiable, yet space availability is a problem, implies that the table is fragmented. Solution, export the segment. recreate and import, fragmentation is eliminated.
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Oracle server down time
what are the necessary steps to be take when server gets down? How can we increase size of a database?
subha gunasekaran
- Jun 5th, 2008
1.Bring up the server. 2.Run the profile of the database 3.Bring up the database. 4.In server prompt, check ps- ef | grep pmon - This is used to check whether the database is up or not. 5.Bring u...
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Why minimum extents are required in roll back segment?
dbashashi
- May 20th, 2008
It is two. It is the minimum no of extents that we can assign to roll back segment.The max extents depends on the version of Oracle being used.
phani99_sakar
- Feb 19th, 2008
The minimum requirement for a DB or to start an instance it is mandatory to have atleast one roll back segment( if we or not ginving it oracle will take it from sys...) that is minimum.....and mandatory.............
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What is the difference between a system crash and a media failure?
dbashashi
- May 20th, 2008
In simple terminology, combination of S/w(Operating system et all) and hardware(Disk Drives) on which these S/W(OS) are loaded, are vital for smooth runing of system. Failure of any of ...
stepwil
- Apr 16th, 2008
A system crash is when an operating system or an application fails corrupting or deleting database objects or the database itself. Media failure is when the hardware that houses the database fails ie: hard disk failure.
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How to provide much and more security to my users in the database?
rajendra_thanekar
- Apr 9th, 2008
Hi,create role in database with proper permission. then assign that role to the user. This is the simplest method to implement secuirty in database.
Yogesh
- Feb 6th, 2007
By providing proper Grants on tables such a (select ,update delete..) to different user a DBA can have a better control over his database and if he finds some problem he can Revoke the given rights of the specified user.
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How do you create a primary key to existing table with duplicate records?
hemant.agarwal03
- Mar 17th, 2008
Alter table add constraint primary key ()DEFERRABLE initially immediate enable novalidate
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Is it possible to disable the connection sys as sysdba. If yes, does violates oracle 9i?
kashyap_aseem
- Feb 14th, 2008
In 10g there is a option to lock an acount we can lock system user through this correct me if i am wrong
Ritesh Raj Singh
- Jul 12th, 2006
There is no possibilities of disabling the connection as sysdba because sys is the owner of the database who has all the powers of the database so you can disable the account of sys what u can do is y...
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What is the default sort order in oracle?
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What is addressing modes? What is a node, How to insert into nodes?
kumar1974
- Jan 22nd, 2008
Dear Pooja your answer is correct. And please write the answer in steps wise or by paragraphs wise.Regardskumar
Pooja Chaturvedi
- Nov 19th, 2006
Addressing modes, a concept from computer science, are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a g...
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What is an intelligent agent?
azam.irshad
- Jan 2nd, 2008
A process that runs on each of the nodes. It functions as the executor of jobs and events sent by the console by way of the mangement server. High availability is ensured since the agent can function regardless of the status of the cosole or network connections
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What is free list group?
azam.irshad
- Jan 2nd, 2008
Sets of free lists available for use by one or more instances.When data is frequently inserted into a table from multiple nodes and the table is not partitioned, use free list groups to avoid performa...
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Whenever a DBA creates a user in which datafile that will be get created ?
None
gbansal4
- Dec 17th, 2007
When the user is created without mentioning default tablespace, then it will be created in SYSTEM tablespace. If Temporary tablespace is also not mentioned then it will automatically take the default temporary tablespace mentioned by the DBA.
Sundar
- Oct 25th, 2007
In MS SQL Server it gets stored in master db.
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Is it advisable to force an index when you want to select most of the entries in the table?
John Netherwood
- Nov 14th, 2007
No it isn't. If you are going to select most of the entries then you will have to read through the entire table anyway. Forcing the use of an index will just be an extra overhead.
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What is a full table scan and what is the ideal rate/min for a FTS?
parthokonar1
- Sep 26th, 2007
FTS means the oracle server reads all the records from the concerned table. And it all depends on the size of the table/ partitioned table. What you say if a table consists of 10 million of records. so we musr avoid FTS. And after all Oracle is build for searching.
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What is the difference between DSS and OLPT
kodaliprakash
- Sep 7th, 2007
DSS is desicion support system. This is mainly useful for tking appropriate decisions based on existing data. All the data is already available in the DB. And we have to get reports according to the n...
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How is locking implemented?
Raghunathan Asari
- Jul 22nd, 2007
Whenever an SQL is issued for execution, DB2 checks for lock avoidance by checking the SQL.Eg. SELECT ...... WITH UR or BIND with ISOLATION (UR) (UR Uncommitted Read)If not DB2 checks&nbs...
Culver_lake
- Mar 19th, 2006
Locking in most modern database management systems is implemented implicitly. That is you never have to ask for a lock nor will you ever fail to release a lock. In DB2 this is all controll...
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