- World's Largest Collection of Interview Questions
Start Your Own website Now
Sponsored Links

Interview Questions
Our Services

Get 9,000 Interview Questions & Answers in an eBook.

  • 9500+ Pages
  • 9000 Question & Answers
  • All Tech. Categories
  • 14 MB Content

    Get it now !!

    Send your Resume to 6000 Companies

    Question :
    What is the exact difference betwwen Join,Merge and Lookup Stage??

    Category DataStage Interview Questions
    Rating (0.4) By 1171 users
    Added on 7/26/2006
    Views 2094
    Rate it!

    The exact difference between Join,Merge and lookup is

    The three stages differ mainly in the memory they use

    DataStage doesn't know how large your data is, so cannot make an informed choice whether to combine data using a join stage or a lookup stage. Here's how to decide which to use:

    if the reference datasets are big enough to cause trouble, use a join. A join does a high-speed sort on the driving and reference datasets. This can involve I/O if the data is big enough, but the I/O is all highly optimized and sequential. Once the sort is over the join processing is very fast and never involves paging or other I/O

    Unlike Join stages and Lookup stages, the Merge stage allows you to specify several reject links as many as input links.

    The three stages differs with each other with respect to
    1>Input Requirements
    2>Treatment of unmatched records
    3>Memory Usage

    Join requires less memory usage
    Lookup requires more memory usage and
    Merge requires less memory usage

    To know more differences, you can mail me. There are almost 12 differences that i can explain you

    Posted by: Vishwanath    

    Contact Vishwanath Contact Vishwanath

    i wnt 2 known more differences,from u.

    Posted by: rasool    

    Contact rasool Contact rasool

    The main difference between the Join,Lookup,Merge is
    1)In the Join stage we can perform 4 Joins i.e Inner join,Left outer Join,Right Outer Join,Full Join.
    2)Join doesn't have Updated link,Reject links.we can't capture unsatisfied condition data.

    1)In the Lookup stage it has only two joins i.e drop(inner),continue(left outer join).
    2)In this we have to mention common column.
    3)Unsatisfied data will come from source only.

    1)The main difference of Merge is
    It has only two Joins i.e drop(inner),keep(loj)
    2)It will work on common key column
    3)The Unsatisfied data will come from Updated link(reference) to Reject link.

    Posted by: pradeep    

    Contact pradeep Contact pradeep

    If you have the better answer, then send it to us. We will display your answer after the approval.
    Rules to Post Answers in

  • There should not be any Spelling Mistakes.
  • There should not be any Gramatical Errors.
  • Answers must not contain any bad words.
  • Answers should not be the repeat of same answer, already approved.
  • Answer should be complete in itself.
  • Name :*
    Email Id :*
    Answer :*
    Verification Code Code Image - Please contact webmaster if you have problems seeing this image code Not readable? Load New Code
    Process Verification  Enter the above shown code:*
    Inform me about updated answers to this question

    Related Questions
    View Answer
    There are three different types of user-created stages available for PX.
    What are they? Which would you use? What are the disadvantage for using each type?

    View Answer
    What user varibale activity when it used how it used !where it is used with real example

    View Answer
    DataStage from Staging to MDW is only running at 1 row per second! What do we do to remedy?

    View Answer
    What is the difference between datastage and informatica

    View Answer
    How is datastage 4.0 functionally different from the enterprise edition now?? what are the exact changes?

    View Answer
    What are orabulk and bcp stages?

    View Answer
    How to handle the rejected rows in datastage?

    View Answer
    It is possible to run parallel jobs in server jobs?

    View Answer
    What are the differences between the data stage 7.0 and 7.5
    in server jobs?

    View Answer
    How the hash file is doing lookup in serverjobs?How is it comparing the key values?

    View Answer
    What is data set? and what is file set?

    View Answer
    What are the enhancements made in datastage 7.5 compare with 7.0

    View Answer
    If I add a new environment variable in Windows, how can I access it in DataStage?

    View Answer
    1.What about System variables?
    2.How can we create Containers?
    3.How can we improve the performance of DataStage?
    4.what are the Job parameters?
    5.what is the difference between routine and transform and function?
    6.What are all the third party tools used in DataStage?
    7.How can we implement Lookup in DataStage Server jobs?
    8.How can we implement Slowly Changing Dimensions in DataStage?.
    9.How can we join one Oracle source and Sequential file?.
    10.What is iconv and oconv functions?
    11.Difference between Hashfile and Sequential File?
    12. Maximum how many characters we can give for a Job name in DataStage?

    View Answer
    It is possible to call one job in another job in server jobs?

    View Answer
    What is hashing algorithm and explain breafly how it works?

    View Answer
    If a DataStage job aborts after say 1000 records, how to continue the job from 1000th record after fixing the error?

    View Answer
    How to implement type2 slowly changing dimensions in data stage?explain with example?

    View Answer
    Is it possible to move the data from oracle ware house to SAP Warehouse using with DATASTAGE Tool.

    View Answer
    How much would be the size of the database in DataStage ?
    What is the difference between Inprocess and Interprocess ?

    View Answer

    Please Note: We keep on updating better answers to this site. In case you are looking for Jobs, Pls Click Here - Best Freshers & Experienced Jobs Website.

    View ALL DataStage Interview Questions

    User Options
    Sponsored Links

    Copyright ©2003-2015, All Rights Reserved.
    Privacy Policy | Terms and Conditions

    Download Yahoo Messenger | Placement Papers| FREE SMS | ASP .Net Tutorial | Web Hosting | Dedicated Servers | C Interview Questions & Answers

    Testing Articles | Testing Books | Testing Certifications | Testing FAQs | Testing Downloads | Testing Interview Questions | Testing Jobs | Testing Training Institutes

    Cache = 0 Seconds