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ETL Interview Questions

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How to write an query for the following?

Asked By: vignesh.testengg | Asked On: Jan 6th, 2014

Say in a source there are 1 lakh records and in target there are 1 lakh records. Some records in a column having the mismatch value (.Ie., instead of displaying 1000 in a column, it is displaying as 100 in target column) the source file is from an db2 and, Oracle (different source) and, target is an...

Answered by: Sathiya seelan on: Jul 23rd, 2014

Read the data from the source and do the lookup on target table and get the column which has different value. Compare it with the current record value. If both are matches, then no issues otherwise load the data into the error table / file.

Answered by: chandu on: Jul 23rd, 2014

But the sources are different.How we will apply minus between source and target and one more thing we cant apply count function for 2 different sources.

What is the difference between a ods and staging area

Asked By: nagireddy | Asked On: Mar 27th, 2007

Answered by: Poomari Manoharan on: Jul 2nd, 2014

ODS is nothing but the Operational Data Store which holds the data when the business gets started. It means , it holds the history of data till yesterdays data(depends upon customer requirement). Some...

Answered by: ram on: Jun 11th, 2013

Yes, ODS is a Open Data Source where it contains real time data (because we should apply any changes on real time data right..!) so dump the real time data into ODS called Landing area later we get the data into staging area here is the place where we do all transformation.

Lets suppose we have some 10,000 odd records in source system and when load them into target how do we ensure that all 10,000 records that are loaded to target doesn't contain any garbage values. How do...

Asked By: Ram | Asked On: Aug 13th, 2006

Answered by: Shwetha Bakkappa on: Jun 5th, 2014

It requires 2 steps:

1.Select count(*) from source
Select count(*) from target

2. If source and target tables have same attributes and datatype

Select * from source
MINUS
Select * from target
Else
We have to go for attribute wise testing for each attribute according to design doc.

Answered by: Grace on: May 29th, 2014

As other posts have mentioned, I would do some of the following: "sql Select COLUMN, count(*) from TABLE group by COLUMN order by COLUMN Select min(COLUMN), max(COLUMN) from TABL...

What are active transformation / passive transformations?

Asked By: Interview Candidate | Asked On: May 8th, 2005

Answered by kiran on 2005-05-08 09:32:14: an active transformation can change the number of rows as output after a transformation, while a passive transformation does not change the number of rows and passes through the same number of rows that was given to it as input.

Answered by: CHOTU JAIN on: Mar 13th, 2014

In expression,we may add extra port which can be used for making calculations on existing table columns.so it will simply calculate value for each record and will give it as output.

Answered by: Suresh G on: May 1st, 2012

Conditional statements are also given in the Expression transformation then why it is passive transformation....

What are the etl tester responsibilities?

Asked By: phani.nekkkalapudi | Asked On: Nov 28th, 2011

Answered by: Uttam22 on: Feb 20th, 2014

A ETL Tester primarily test source data extraction, business transformation logic and target table loading . There are so many tasks involved for doing the same , which are given below - 1. Stage tab...

Answered by: radhakrishna on: Nov 4th, 2013

ETL tester responsibilities are: writing sql queries for various scenarios like count test, primary key test, duplicate test, attribute test, default check, technical data quality, business data qua...

Find out the number of columns in flat file

Asked By: kishore.vakalapudi | Asked On: Aug 3rd, 2010

In etl testing if the src is flat file, then how will you verify the data count validation?

Answered by: JeffManson on: Feb 13th, 2014

Not always (in my experience, quite rarely in fact). Most often the flat file is just that, a flat file. If in UNIX, the wc command is great, in Windows, one could open the file in notepad and CTRL+...

Answered by: Radhakrishna on: Nov 13th, 2013

To find the count in flat file, you have to import that file into excel sheet (use Data->Import External Data->import data) and find the count of records using count() [goto Insert->function->count->] in excel....

What is latest version of power center / power mart?

Asked By: Interview Candidate | Asked On: Jun 5th, 2005

Answered by: Mark Rutherford on: Jun 17th, 2013

9.5.1

Answered by: Kumar on: Nov 17th, 2012

9.5

Test objective is to.

Asked By: sandydil | Asked On: Mar 7th, 2013

1.To find faults in software 2.To purify that software has no defects. 3.To find perform problems. 4.To give cunt in software. select best option.

List of all the etl and reporting tools available in the market

Asked By: perlamohan | Asked On: May 28th, 2008

Can any one let me know where can I find the list of etl & reporting tolls available in the market. Thanks in advance

Answered by: Michael on: Feb 27th, 2013

Add InetSofts Style Report to the list of BI reporting tools

Answered by: sajid on: Feb 22nd, 2013

Hi, i would like share my knowledge on this. ETL Tools: Ab Initio, BusinessObjects Data Integrator, IBM InfoSphere DataStage, Informatica, Oracle Warehouse Builder, SQL Server In...

What are the testings performed in etl testing?

Asked By: sindhugowda | Asked On: Jan 23rd, 2013

Answered by: jatin on: Feb 7th, 2013

Data-Centric Testing: Data-centric testing revolves around testing quality of the data. The objective of the data-centric testing is to ensure valid and correct data is in the system. Following are th...

Etl testing in Informatica

Asked By: phani.nekkkalapudi | Asked On: Nov 28th, 2011

As an etl tester what are the things to test in Informatica tool. What are the types of testing has to do in Informatica and the things to test in each type? If there is any documents on etl testing

Answered by: lakshmi on: Jan 31st, 2013

ETL Testing in Informatica: 1. First check the workflow exist in specified folder. 2. Run the workflow. If the workflow is success then check the target table is loaded on proper data else we can nee...

Answered by: Lokesh M on: Feb 18th, 2012

- Test ETL software. - Test ETL datawarehouse components. - Executing backend data-driven test. - Create, design and execute test plans, test harnesses and test cases. - Identify, troubleshoot and pro...

If lkp on target table is taken, can we update the rows without update strategy transformation?

Asked By: srilu.srilatha | Asked On: Apr 8th, 2007

Answered by: Shiv on: Oct 11th, 2012

Hi, If you even do dynamic lookup you should make use of update strategy to mark the records either to insert or update in the target using look-up cache (look-up will be cached on target). your re...

Answered by: sn3508 on: May 12th, 2008

Update strategy transformation determines whether to insert, update, delete or reject a record for the target.  We can bypass update strategy transformation by creating a router to divide ro...

Clean data before loading

Asked By: riyazz.shaik | Asked On: Sep 17th, 2008

Why is it necessary to clean data before loading it into the warehouse

Answered by: Prashant Khare on: Oct 3rd, 2012

Data Cleansing is a process of detecting and correcting the corrupt and inaccurate data from table or database.
There are following steps used:-
1) Data auditing
2) Workflow Specification
3) Workflow Execution
4) Post-processing and controlling

Answered by: 32kris on: Aug 11th, 2010

Cleaning is required as it helps in maintaining the uniforminty of the target data.

Informatica: if flat file name varies day by day ...

Asked By: Mahendra | Asked On: Nov 16th, 2011

If we are using flat file in our loading, and flat file name change daily so how we handle this without changing file name manually daily? for example: like file name is changing depend on date so what should I do? Pls help…

Answered by: Charu on: Jan 24th, 2012

Use the indirect filelist option at informatica session. say the filelist name is daily_file.txt put a shell script daily_filename.sh at the pre-session command. The content of daily_filename.sh is ...

Answered by: SHIV on: Dec 28th, 2011

You can use Informatica File List option in target to get the dynamic file names along with the transaction control transformation so that you can create dynamic filenames based on some transaction properties.....




What are the different lookup methods used in Informatica?

Asked By: Interview Candidate | Asked On: Sep 9th, 2005

Answered by: SHIV on: Dec 28th, 2011

The main difference between connected and unconnected lookup is, we can call unconnected lookup based on some conditions but not the connected lookup.

Answered by: Sreedhar Lokaray on: Nov 2nd, 2011

Lookup can be used as Connected or Unconnected. Apart from cache and receiving input values from pipe line, there is one more difference. If you want to use the same lookup more than one in a mapping ...

How do you implement the concept of reusability in microstrategy?( as in Informatica it is done by creating mapplets.)

Asked By: arjunsarathy | Asked On: Jan 2nd, 2006

Answered by: Doyel Ghosh Dutta on: Sep 16th, 2011

I think in microstrategy view can be reusable object.

How to check the existence of a lookup file in a graph ?

Asked By: debashish29 | Asked On: Sep 9th, 2011

How to check the existence of a lookup file in a graph ..The requriement is if lookup file is present then some search will be carried out in the same else default value will be set. Please note we need to check the existence of the lookup file in graph level only..

What is a mapping, session, worklet, workflow, mapplet?

Asked By: Interview Candidate | Asked On: Aug 29th, 2005

Answered by: kotesh chowdary on: Aug 26th, 2011

SIMPLY to say::::::::::::::::::

worklet : set of sessions

mapplet : set of transformations that can be called within a mapping

Answered by: Naveen on: Aug 22nd, 2011

Mapping :-set of transformations.And moving data from source to target along with transformation s

session :-set of instructions source addresses and target address u write it

worklet:- set of sessions

Cache files

Asked By: YugandharS | Asked On: Jul 27th, 2010

What are the t/rs which create cache files?

Answered by: deepthi on: Aug 20th, 2011

Aggregator
joiner
lookup
rank
sorter

Answered by: shiva on: Jul 22nd, 2011

Actually the answer is partially related to the Question.......

t/rs like Joiner, Lookup, Aggregator,Rank Transformations uses the Caches.....

How do we call shell scripts from Informatica?

Asked By: Interview Candidate | Asked On: May 27th, 2005

Answer posted by staline on 2005-05-27 00:42:44: you can use a command task to call the shell scripts, in the following ways:  1. Standalone command task. You can use a command task anywhere in the workflow or worklet to run shell commands.  2. Pre- and post-session shell command. You can call...

Answered by: Hanuma on: Jul 24th, 2011

You can use a Command task to call the shell scripts, in the following ways: 1. Standalone Command task. You can use a Command task anywhere in the workflow or worklet to run shell commands. 2. Pr...

Answered by: praveenathota on: Nov 12th, 2006

Hi,There are two ways to do this,they are as follows:1)we can use a command task anywhere  in the workflow or worklet to run the shell commands.2)In the session task,we can call reusable command ...

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