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Group By
Can you select any column in a Group by query even if that column is not groupable?e.g. Select Dept, Empno, Ave(salary) From T1 Group by DeptCan we select empno in the above query?
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Referential Integrity
Which one of the following does not help to maintain referential integrity?a. Unique constraintsb. Primary keysc. Cascading actions d. Foreign keys
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What happens when more than one row satisfies a Select statement that is executed outside of any cursor processing?
pawan_singh
- May 14th, 2010
If you using just a simple select SQL statement and it is giving you more than one row as output than you will get a SQL code retrun -811. To avaoid this depending your requirement you can modify your query or if you need more than one row than just use cursor.ThanksPawan
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Attributes to Read & Write DB2 file
What are the attributes that needs to be defined in order to read & write DB2 file in Cobol program?
shak_techm
- May 26th, 2010
To see the attributes of RW DB2 file do the following:Go to DB2 regionSelect 3 admin tool1 - DB2 system catalogT - Tables, views, and aliasesD - DatabaseDIS - Display databaseYou will get screen ...
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What is normalization and what are the five normal forms?
Normalization is a design procedure for representing data in tabular format. The five normal forms are progressive rules to represent the data with minimal redundancy.
muamee
- Jun 14th, 2010
Normalization in DB2 is used to reduce data redundancy and maintain integrity.There are 4 types normalization1st type: Every instances of an entiry should contain only one value.2nd type: Each at...
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Bind process
What happens during pre-compilation and finally bind process?
naga1126
- Jun 16th, 2010
Bind process is mainly for two processes:1. To syntax check the Query (To see the Columns and tables referred are actually present etc. )2. To find the efficient access path.Result of Bind is an Executable form of the DBRM.
yuvaevergreen
- Apr 11th, 2010
Precompilation:Separates out the SQL statements in the COBOL program and creates the DBRM.BIND:Creates the executable format of DBRMs.
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What techniques are used to retrieve data from more than one table in a single SQL statement?
Joins, unions and nested selects are used to retrieve data.
AR
- Mar 16th, 2007
The two tables has to be linked.EXEC SQL
SELECT A.EMP_ID, B.WAGE FROM Table1 A, Table2 B WHERE A.EMP_ID = B.EMP_ID
AND A.EMP_ID = 100001 END-EXEC. -
Explain the use of the WHERE clause. WHERE is used with a relational statement to isolate the object element or row.
Srinivas17738
- Aug 17th, 2010
1. WHERE clause is used to filter the result set records with different predicates like -- BETWEEN, =, = and many more....2. WHERE Clause is used to Isolate rows.
mahadev mahajan
- Sep 30th, 2005
where clause is use to extrct only one record.it is used with GROUP BY CLAUSE. EG:-SELECT DNO FROM EMP WHERE SAL=4200 ...
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Locked Space
What is meant by locked space? Describe locking concepts?
vjjammi
- Aug 25th, 2010
DB2 Supports Locking mechanism at three levels. 1. Space Level. 2. Table Level. 3. Page Level. The above hierarchy has some significance and in order to lock a page at the higher level, you needn&#...
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A table called EMPLOYEE has the following columns: name, department, and phone_number. Which can limit read access to the phone_number column?
A table called EMPLOYEE has the following columns: name, department, and phone_number. Which of the following can limit read access to the phone_number column? A. Using a view to access the table B. Using a referential constraint on the table C. Revoking access from the phone_number column D. Defining a table check constraint on the table
davindersingh29
- Jun 22nd, 2009
A. Using a view to access the tableOne should create a VIEW, this way the phone number column can be made read only.
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What is cursor stability?
Cursor stability means that DB2 takes a lock on the page the cursor is accessing and releases the lock when the cursor moves to another page.
sintalam4
- Dec 21st, 2010
The Cursor Stability (CS) isolation level is the default isolation level and locks any row on which the cursor is positioned during a unit of work. The lock on the row is held until the next row is fe...
radibioinfo
- Oct 2nd, 2007
Cursor stability isolation level ensures that any row that was changed by an application process cannot be read untill committed by that process. It ensures that the current row of every updatab...
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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.
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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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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 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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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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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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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. -
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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What is a DB2 plan?
An application plan or package is generated by the bind to define an access path.
DB2 Interview Questions
Ans