Saturday, May 28, 2011

Interview Question&ANSWERS-1



1.How could we generate the sequence of key values without using sequence generator transformation in the target ??
TAKE EXPRESSION TRANSFORMATION AND DOUBLE CLICK ON THE
EXPRESSION TRANSFORMATION AND ADD TWO NEW PORTS
1.SEQ
2.SEQ_OUT

1.IN THE SEQ PORT CHECK V=VARIABLEPORT THERE YOU MENTION
EXPRESSION SEQ+1.
2.IN THE SEQ_OUT PORT CHECK O=OUTPUTPORT THERE YOU MENTION
EXPRESSION IIF(ISNULL(SEQ),O,SEQ)
IT WILL GIVE CORRECT RESULT

2. Normalizer transformation is not involved in Mapplet.. why???
Mapplet is a reusable logic that you can use acrossdifferent mappings. Normalizer is a dynamic transformation
which converts rows to columns or vice-versa, so that is dependendent on the input to the normalizer, it is not
fixed logic that you can reuse in other mappings.
 
3. Re: i want to load data in to two targets..one is dimension table and the other is fact table?how can i load ata a time?
Using dynamic lookup, you can load both simultaneously.
 
4.  what is shortcut in informatica? difference between shortcut,reusable object?
Short cut is a referenced object.We cannot edit on short cut objects.Shortcut objects are present under 
shared folder.Mostly sources and targets will be the shortcut objects.Reusable object can be used multiple
times in a mapping.short cuts can be used in all the folders available in that repository, but reusable objects 
are limited to that folder.
 
5. can v update d records in target using update stargey   
without generationg  primary key ? explain
 no using update strategy without primary keys update is not possible. try and read teh session log file once. 
it will display a msg updates are not supported without primary keys.update override in the target is to update
 the function in the update strategy t/tion and it updates only on non-primary key columns like dname, loc but not on deptno.
 
6. What is the exact difference b/w IN and EXIST in Oracle..?
EXIST is used as conditional operator in which u can write a queryIN is also used as a conditional operator in 
which we gives a list of elements

7. what is threshold error in informatica?
When the target is used by the update strategy DD_REJECT,DD_UPDATE and some limited count, then if it the number 
of rejected records exceed the count then the session ends with failed status.  This error is called Threshold Error.

8.  If the values in a row are 1,2,3,3,4,,4,5 then how a rank transformation can rank these values
   1,2,3,3,4,,4,5 
ANS:1,2,3,3,5,5,7

9.  In seqence generator transformation maximum limit is reached,after reaching maximum limit how will u insert the data
When a Seq Gen Transformation reaches its maximum value and the sequence is not configured to cycle, the session fails
.Either you need to cycle the sequence or increase the end value.

10. i have 2 flat files one table contains duplicates another one no duplicates.... so i need like this i don't want duplicates...pl's give me ans...
place sorter transformation after source qualifier of duplicates flatfile and enable property distinct

11.  what is meant by data driven.. in which scenario we use that..?
data driven is available at session level.it says that when we r using update strategy t/r ,how the integration service 
 fetches the data and how to update/insert row in the database log.
Or
you can select the data driven option, where the Integration Service follows instructions coded into Update Strategy 
transformations within the session mapping.

12. Can we lookup a table from source qualifier transformation. ie. unconnected lookup
You cannot lookup from a source qualifier directly. However, you can override the SQL in the source qualifier to join with the lookup table to perform the lookup.

13.how can we stop batch
By using server manager or pmcmd.

14. Batches - It Provides A Way to Group Sessions For Either Serial Or Parallel Execution By The Informatica Server. There Are Two Types Of Batches :

15.Can u start a batches with in a batch?
U can not. If u want to start batch that resides in a batch,create a new independent batch and copy the necessary sessions into the new batch.

16.Can u start a session inside a batch idividually?
We can start our required session only in case of sequential batch.in case of concurrent batch
we cant do like this.


17. whether Sequence generater T/r uses Caches? then what type of Cache it is
the seq t/r uses index cache for the sequential range of numbers for the generated keys.

18. HOW DO YOU CONNECT TO REMOTE SERVER ?
USING FTP THRU TELNET/PUTTY/COMMAND PROMPT
 V CAN CONNECT TO REMOTE SERVERS..

19. What is a command that used to run a batch?
pmcmd is a command line programme. this can be used to stop,run and abort the session.

20. If i done any modifications for my table in back end does it reflect in informatca warehouse or maping desginer or source analyzer?
NO. Informatica is not at all concern with back end database.It displays you all the information  that is to be
stored in repository.If want to reflect back end changes toinformatica screens, again you have to import from back endto
 informatica by valid connection.And you have to replacethe existing files with imported files.

21. how many repositories can v create in informatica .
2 types of repositories can be created
1. standalone
2. Shared or Global repository

22. in which situations we go for pesistent cache in lookup  and 
which situations go for shared lookup cache?

If the lookup does not change between sessions, you can configure the transformation to use a persistent
 lookupcache. When you run the session, the Integration Service rebuilds the persistent cache if any cache file 
is missing or invalid.

23. What are the data movement modes in informatcia?
Datamovement modes determines how informatcia server handlesthe charector data.yoU choose the datamovement in 
the informatica server configuration settings.Two types ofdatamovement modes avialable in informatica.

 ASCII mode
 
Uni code mode

24. How many ways you create ports?
1.Drag the port from another transforamtion
 2.Click the add buttion on the ports tab.

25. How do you create single lookup transformation using multiple tables?
we have the lOOKUP OVERRIDE Query in the Lookup transformation. Use the SQl Query to join the tables 
you lookup on.Thsi is similar to what yo do at the Source Qualifier

26.Discuss which is better among incremental load, Normal Load and Bulk load

It depends on the requirement. Otherwise Incremental load which can be better as it takes only that data which is not available previously on the target.

27. What is the difference between Informatica server, Repository Server and Power center Server ?

Informatica Server and PowerCenter Server both mean the same. It is concerned with running of sessions and workflows.
The Repository Server or the Informatica Rep Server is concerned with connecting to the repository through the Rep Agent. One Repository Server can connect to many repositories at a time.
For the PowerCenter Server to be up and working it is necessary that the Repository Server is running.



According to performence bulk is better than normal.
But bolh having some conditions in source data
Conditions are like
1)does not containn any constraint in data.
2)dont use the double datatype if neccesory to use then use it as last row of the table.
3)it does not support

28. ow can we access MAINFRAME tables in INFORMATICA as a source ?

We got mainframe source as VSAM (Virtual Storage Access Method) files mainframe developers 
converts these files as Flat files to access data into Informatica for our convenience. The bottom line is 
The mainframe data files are in .Dat files(Flat Files) .


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