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What is the self-referencing constraint?
A31. The self-referencing constraint limits in a single table the changes to a primary key that the related foreign key defines. The foreign key in a self referencing table must specify the DELETE CASCADE rule.
Sandhya.Kishan
- Jul 9th, 2012
Self-referencing constraint makes the table both the parent and dependent table in the same referential constraint.
Here the table is created first and then the foreign key is defined to that table. -
How does Db2 use multiple table indexes?
DB2 use the multiple indexes to satisfy multiple predicates in a SELECT statement that are joined by an AND or OR.
Sandhya.Kishan
- Jul 9th, 2012
By using the concept of list prefetch DB2 uses multiple index processing.I is used to satisfy multiple predicates in a select statement that are joined by an AND or OR.
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What is a root page?
The opposite of a leaf page; it is the highest level index page. An index can contain only the one root page; all other index pages are associated to the root.
Sandhya.Kishan
- Jul 9th, 2012
The indexes of DB2 are represented using b-tree,the b-trees top page is called as the root page.The root page entries represent the upper range limits of the index and are referenced first in a search.
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What is an asynchronous write?
. It is a write to disk that may occur before or long after a commit. The write is controlled by the buffer manager.
krsna
- Jun 7th, 2012
Asynchronous write is when the pages from bufferpool is written to disk by the page cleaners.
Sandhya.Kishan
- Apr 6th, 2012
Asynchronous write is a function where the the function call immediately returns after the operation was enqueued or if before this happens an error was encountered.This function is present in "aio.h"...
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How can you split db2 table in to exactly half?
Can we divide it row wise or col wise.?is there any query for this.?
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-811 abend
When will occur -811 abend? how will u resolve the -811 abend?
rasheeed17
- Jan 19th, 2012
- You will get -811 abend when your SQL query returns more than one record. - COBOL do not have ability to handle more than one db2 record at a time. - You must USE CURSOR If your query returns mor...
6983manish
- Nov 12th, 2011
If the need is to get any of the row qualified for the predicates given , you can use "Fetch First 1 Row Only" with your select query.
OR
If you are interested all the data qualified for the query , there is no option except the use of Cursors. -
I have 1000 records in vsam,I want to read records 500 to 900?
prasenjit_in
- Sep 2nd, 2008
last 2 who answered the query didnt you see that its a VSAM based question...dont just put up anything and everything.
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How the durability(one amongst the ACID model) of database is achieved while loading table with 'Log No' option?
manasa
- Nov 4th, 2011
When we load data with LOG NO then the table goes to copy pending status and is not available for updating..
It can be accessed for read only.
So,we need to take a image copy which will change the copy pending status to RW.
This IC will be used as a backup and thus durability can be achieved. -
Given a read-only application that requires consistent data for every query, which isolation levels should it use to provide the most concurrency with other applications doing updates?
Given a read-only application that requires consistent data for every query, which of the following isolation levels should it use to provide the most concurrency with other applications doing updates? A. Read Stability B. Repeatable Read C. Cursor Stability D. Uncommitted Read
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What is the full form of DBRM ?
a.Database Restrict Modelb.Database Resurrect Modelc.Database Request Moduled.Database Reference Modulee.Database Restrict ModuleDatabase Request Module
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What is a DB2 plan?
An application plan or package is generated by the bind to define an access path.
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DB2 Large Objects (LOB) Columns
In DB2, Large Objects (LOB) Columns are used to store large objects (Documents, pictures, voice, and mixed media) in database. Which of the following clauses can't be used on LOB columns?a) GROUP BYb) HAVINGc) ORDER BYd) NONE OF THE ABOVE
kris mohan
- Sep 13th, 2011
None of the above
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Can an index of a table be displayed using 'DISPLAY' ?
BrantleyL1
- Jul 27th, 2011
However, here is an easy solution:
code in ws...
01 ws-index pic S9(8) comp.
set ws-index to (table-index)
display ws-index. -
What is the difference between IN subselects and EXISTS subselect?
If there is an index on the attributes tested an IN is more efficient since DB2 uses the index for the IN. (IN for index is the mnemonic).
nlarsensmith
- Feb 22nd, 2011
***IN***IN subselects perform search on a list of values returned by the subquery.ex)select * from table1 where col1 IN(select col1 from table2 where <some condition>)-Based on the range of...
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What is tablespace?
Tables are stored in tablespaces (hence the name)! There are three types of tablespaces: simple, segmented and partitioned.
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How to find out the middle row of Employee table?
chanukya
- Aug 19th, 2011
You can write like top 50 percent after sorting.
please correct me if i am wrong...sethy.pradeep
- Nov 19th, 2008
For getting middle of rows for employee table first you should SORT the order of rows in a table after that you can put it skip/count logic on that.Regards,Pradeep
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Explain an outer join?
An outer join includes rows from tables when there are no matching values in the tables.
lrsantosh
- Aug 18th, 2011
Outer Join is a type of join where the matching rows from the given tables are selected for sure and it follows following criteria to select unmatched rows. 1. LEFT OUTER JOIN it will give All Matchin...
prasenjit_in
- Sep 2nd, 2008
3 types. Left outer Join----left table unmatched valyes are included.Right Outer Join---right table unmatched values are included.Full outer Join----Both table unmatched values are selected.
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How to read last record in vsam file.,I don't know how many records are there?
BrantleyL1
- Jul 27th, 2011
This only works in CICS. Batch programs do not have the read previous record option.
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DB2 WITH HOLD option
What does WITH HOLD option do ?forces cursor to close after commitb.Keeps cursor open after commitc.Does not allow cursor to close till all rows are fetchedd.Locks the cursore.None of the aboveKeeps cursor open after commit
prasadkss
- Dec 4th, 2009
When a commit is issued by a program all the cursors opened by that program are closed, but WITH HOLD option is used to retain the cursor pointer, even if the commit is used.
DB2 Interview Questions
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