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Thread: Table Input Step

  1. #1
    Join Date
    Sep 2008
    Posts
    1

    Smile Table Input Step

    Hi

    I have a few queries related to kettle.

    1. We are facing a problem while trying to substitute '?' in the SQL of a table input step, by inserting data from a previous step. Though it works 99% of the times, it fails once a while with error ' Expected to read values from step [Select values] but none were found '. While browsing through the forums i understand that we can not 'Set' and 'Get' a variable in the same transformation. By 'Setting a variable in the same transformation', do you mean a 'SET Varaiable step' or any step that sets a variable? The steps that we use before table input are 'Get' variable, 2 java scripts & a Select value. We do not use a 'Set variable step' per se. However, all over the forum it seems to insist that i enable ' Execute for each row' if i'm inserting data from a previous step. Does 'Execute for each row' ensure that the step from which i insert data, is exectued before the 'Table input' step is executed?

    2. I understand from the forum that the steps in a transformation execute in parallel unless it's an input step that expects to read variables from a previous step. If the steps don't execute in a sequential order, then what is the significance of a Hop and a direction for the hop?

    3. In the kettle documentation for Table Input step, i read '
    Execute for each row - Enable this option to perform the data insert for each individual row. '. I'm not sure what we mean by 'individual row' in this description. I have a SQL in whose WHERE clause i have a list of ? to be substituted with data from previous step. In this scenario what does 'Individual row' mean? Is it for each row that the SQL will return? Or is there a concept of Row of data incoming for Table input step ( from previous steps )?

    For past few weeks we have been facing this problem of 'Expected to read values from step, but didn't get any'. Can you please answer to my above queries so that i can take a call as to how to fix my problem?

    Thanks a ton for reading till here.

    Regards
    Sangeetha

    Last edited by sprakash; 09-16-2008 at 06:09 AM.

  2. #2
    Join Date
    May 2006
    Posts
    4,882

    Default

    For your 'expected to read values from'.... in some cases you don't send input to the tabel input step... maybe something to do without use of variables.

    1) any step that sets a variable... steps runs in parallel so you don't know when exactly another step will read the value you set (it may be before you set it).

    2) all steps execute in parallel (in <= v3.1), a hop is (possible) flow of data. The table input in your case is running but waiting for input if you switch on the right options in your table input dialog.

    3) For each input row.

    Regards,
    Sven

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