DataStage Interview Questions Answers

3/06/2010 5 Comments

DataStage Interview Questions with Answers.

Explain what is the significance of Surrogate Key in Data warehousing?
Answer :
Surrogate Key is a Primary Key for a Dimension table. Most importance of using it is it is independent of underlying database. i.e Surrogate Key is not affected by the changes going on with a database

Can you tell me what does a Config File in parallel extender consist of in Datastage?
Answer :
 The Config file consists of the following. 

a) Number of Processes or Nodes. 
b) Actual Disk Storage Location.

From how many places you can call the Routines in Datastage?
Answer 
: There are four places from where you can call the Routines

  • Transform of routine (A) Date Transformation (B) Upstring Transformation 
  • Transform of the Before and After Subroutines
  • XML transformation
  • Web base
Explain how would you handle an 'Aborted' sequencer in Datastage?
Answer :
In almost all of the cases, we need to delete the data inserted by this from DB manually and fix the job and then run the job again.


What is the difference between ODBC and Plug-In stages as far as pros and cons are concerned?
Answer :
ODBC :

  • Poor Performance.
  • Can be used for Variety of Databases.
  • Can handle Stored Procedures.
Plug-In: 
  • Good Performance. 
  • Database specific.(Only one database)
Explain about the functionality of Link Partitioner and Link Collector?
Answer :
 Containers is a collection of stages used for the purpose of Re-usability. There are 2 types of Containers. a) Local Container: Job Specific b) Shared Container: Used in any job within a project.

Explain about Dimension Modelling types along with their importance
Answer :
Data Modelling is Broadly classified into 2 types. a) E-R Diagrams (Entity - Relatioships). b) Dimensional Modelling.


Explain how did you connect with DB2 in your Datastage project?
Answer :
 In most of the cases, the data was sent to us in the form of flat files. The data is dumped and sent to us. In some cases were we need to connect to DB2 for look-ups as an instance then we used ODBC drive.

Describe the commonly used Stages or stages you worked with in your project?
Answer :
 The most commonly used stages are cited below.

A) Transformer, ORAOCI8/9, ODBC, Link-Partitioner, Link-Collector, Hash, ODBC, Aggregator, Sort.

Can you tell how many jobs have you created in your project?
Answer :
150+ jobs for every 8 months if you are in Development, if you are in testing 60 jobs for every 6 months although it need not be the same number for everyone across organization and projects.

Have you updated the DS versions like DS 5.X, if yes, then describe the steps you have taken in doing ?
Answer :
Yes, I have updated. The below are some of the steps;

  • Always ensure that you take a back up of the whole project(s) by exporting the project as a .dsx file.
  • Ensure that you are using the same parent
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5 comments :

  1. Most questions are still valid today. It would be great if some more update one are added. E.g. those latest update in transformer in recent version, v7 or even v8 ...

    ReplyDelete
  2. Will update soon.Thanks for the feedback

    ReplyDelete
  3. For the question about Link partitioner and link collector
    The answer specified is not correct.the question is not containers

    ReplyDelete
  4. Functionality of link partitioner and link collector-
    link partitioner- diversifies the data into different outputs/links
    link collector- collects the data from various links to a single output


    ReplyDelete
  5. Aired AdminApril 25, 2016

    Thanks Alice Joy for correcting

    ReplyDelete

 

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