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Thread: Table input versus lookup step

  1. #1

    Default Table input versus lookup step

    kettle version : 4.0.1

    Hi All,

    In one of my transformation i have a Table Input step that first queries database-1 to get a date. The output (i.e. date) will be fed to a second Table Input step that uses it against database-2

    In this scenario, which of the following is the best option?

    1. Table-Input-1 --------------------> Table-Input-2

    2. Table-Input-1 --------------------> Databse-Lookup (or Database-Join)

    As per my understanding, in #1, the fields available (in stream) before Table-Input-1 will NOT be available after Table-Input-2.

    And in #2, the fields available (in stream) before Table-Input-1 will also be available after the look-up step.

    Would be very grateful if any one can shed a light on this scenario.

    Thanks in advance,
    Rakesh
    Last edited by rakcheru; 10-04-2011 at 12:16 AM.

  2. #2
    Join Date
    Jan 2006
    Posts
    245

    Default

    Your understanding is correct. In your #1 case the incoming fields are only used to feed the 2nd table input step, they don't have any other meaning in the context of the transformation and so they will die there. In case #2 that fields also participate to the transformation flow so they go through.

    Which of the two choices is better depends on your needs.

    I hope this helps

    S.
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