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Thread: Select&Alter Step + "Couldn't Find Field In Row" Message

  1. #1

    Default Select&Alter Step + "Couldn't Find Field In Row" Message

    Hi all.
    I've seen this query pop up a few times on the forum and never seen a positive answer to it.

    I have a transformation that renames a number of fields using the Select&Alter step. Used the same step for similar things many times in the past. For a small number of transformations I've built recently, they randomly fail with a "Field X couldn't be found in row" type messages and field X is always one of the fields I've renamed (and always the pre-rename field name).

    Whats even weirder is that simply re-running the transformation results in a success??? I'm assuming that theres something in the order of running within the transformation that causes this error sometimes but can't be sure what.

    Does anyone have any suggestions?

    Many Thanks
    Dave

  2. #2
    Join Date
    Jun 2012
    Posts
    5,534

    Default

    You're right, this topic is an oldie but goldie
    So long, and thanks for all the fish.

  3. #3

    Default

    Thanks for the reply marabu - I'll take a look at that topic later.

  4. #4

    Default

    Hi marabu/all.

    I'm still struggling with this issue. My original issue was with the Select & Alter step complaining fields weren't present in the row when trying to rename them from "field A" to "fieldA" for example to make it a bit more Java friendly. I tried to work around this, thinking that I could create a new field called fieldA and populate it with the values from "field A" but then I get the "Field X couldn't be found in row" message on the Set Field Value step.

    Weirdly, we have pretty much the exact same transformation running for another project which has never had this problem.

    Could it be the way that PDI processes rows? Could I need some hold steps to prevent records from being processed until others have? The transformation I'm having a problem with is called by another 'master' transformation which calls my problem sub-transformation as well as another which also creates text outputs...

    Any help appreciated.
    Dave

  5. #5
    Join Date
    Apr 2008
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    4,696

    Default

    Make sure you are only using one tab of the Select Values step.
    If you are using more than one, it has a habit of getting angry.

  6. #6
    Join Date
    Jun 2012
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    Default

    @Dave: Can you fix up a small self contained demo that we can run on our machines?
    So long, and thanks for all the fish.

  7. #7

    Default

    I'll try and knock something together. Its the random nature of the error that is throwing me which is leading me to think that 'something' is getting processed and the field removed but there is literally nothing in the entire transformation and its sub-transformations that would do this...

  8. #8
    Join Date
    Apr 2008
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    Quote Originally Posted by DavidCBarnett View Post
    and its sub-transformations that would do this...
    Are you using the "Mapping" step to do sub-transformations?

  9. #9

    Default

    Hi gutlez. Yes, the Simple Mapping step is what we're using. What I've noticed is that the "Ask these values to be renamed back on output" option is ticked. What is the effect of using this option AND using the Select & Alter step in the sub-transformation to rename the field?

  10. #10
    Join Date
    Apr 2008
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    Default

    Generally, I recommend staying away from that step.
    I have only rarely had it work the way I would expect it to.

    If you take it out, and move the logic to the parent transformation, the logic will likely work.

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