DataStage Interview Questions and Answers,Solution and Explanation - Part4

What versions of DS you worked with?
Ans:
DS 7.0.2/6.0/5.2

If worked with DS6.0 and latest versions what are Link-Partitioner and Link-Collector used for?
Ans:
Link Partitioner - Used for partitioning the data.Link Collector - Used for collecting the partitioned data.

How do you rename all of the jobs to support your new File-naming conventions?
Ans:
Create a Excel spreadsheet with new and old names. Export the whole project as a dsx. Write a Perl program, which can do a simple rename of the strings looking up the Excel file.

Explain the types of Parallel Processing?
Ans:
Parallel Processing is broadly classified into 2 types. a) SMP - Symmetrical Multi Processing. b) MPP - Massive Parallel Processing.

Does the selection of 'Clear the table and Insert rows' in the ODBC stage send a Truncate statement to the DB or does it do some kind of Delete logic.
Ans:
There is no TRUNCATE on ODBC stages. It is Clear table blah blah and that is a delete from statement. On an OCI stage such as Oracle, you do have both Clear and Truncate options.

When should we use ODS?
Ans:
DWH's are typically read only, batch updated on a scheduleODS's are maintained in more real time, trickle fed constantly

What is the default cache size? How do you change the cache size if needed?
Ans:
Default cache size is 256 MB. We can incraese it by going into Datastage Administrator and selecting the Tunable Tab and specify the cache size over there.

What are the types of Parallel Processing?
Ans:
Parallel Processing is broadly classified into 2 types. a) SMP - Symmetrical Multi Processing. b) MPP - Massive Parallel Processing.

How to handle Date convertions in Datastage ? Convert a mm/dd/yyyy format to yyyy-dd-mm?
Ans:
We use a) "Iconv" function - Internal Convertion. b) "Oconv" function - External Convertion. Function to convert mm/dd/yyyy format to yyyy-dd-mm is Oconv(Iconv(Filedname,"D/M

Differentiate Primary Key and Partition Key?
Ans:
Primary Key is a combination of unique and not null. It can be a collection of key values called as composite primary key. Partition Key is a just a part of Primary Key.

Is it possible to calculate a hash total for an EBCDIC file and have the hash total stored as EBCDIC using Datastage ?
Ans:
Currently, the total is converted to ASCII, even tho the individual records are stored as EBCDIC.

How do you merge two files in DS?
Ans:
Either used Copy command as a Before-job subroutine if the metadata of the 2 files are same or created a job to concatenate the 2 files into one if the metadata is different.

How did you connect to DB2 in your last project?
Ans:
Using DB2 ODBC drivers.

What is the default cache size? How do you change the cache size if needed?
Ans:
Default cache size is 256 MB. We can incraese it by going into Datastage Administrator and selecting the Tunable Tab and specify the cache size over there.

What are Sequencers?
Ans:
Sequencers are job control programs that execute other jobs with preset Job parameters.

How do you execute Datastage job from command line prompt?
Ans:
Using "dsjob" command as follows. dsjob -run -jobstatus projectname jobname

How do you rename all of the jobs to support your new File-naming conventions?
Ans:
Create a Excel spreadsheet with new and old names. Export the whole project as a dsx. Write a Perl program, which can do a simple rename of the strings looking up the Excel file. Then import the new dsx file probably into a new project for testing. Recompile all jobs. Be cautious that the name of the jobs has also been changed in your job control jobs or Sequencer jobs. So you have to make the necessary changes to these Sequencers.

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