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Thread: MongoDB Output plugin - how to update by querying _id field ?

  1. #1
    Join Date
    Jul 2016
    Posts
    1

    Default MongoDB Output plugin - how to update by querying _id field ?

    Hi,

    I am trying to update a mongodb document by specifying _id field for the query match. I am using mongodb output component.
    I am not able to specify the query criteria as below

    {"_id" : ObjectId("579c18b47f34b4330f85a981")}

    Instead the query is getting created as

    {"_id" : "579c18b47f34b4330f85a981"}

    with this query is not finding the document, and the update operation fails with the error No fields to update have been specified for modifier update operation!


    I
    am getting the id to be passed as a string from the previous step, and setting _id as the match criteria in the "Mongo Document Fields" tab.

  2. #2
    Join Date
    Oct 2016
    Posts
    1

    Default

    OK Everyone, I've FINALLY figured this out!


    1. MongoDB Import: Set it up as you would expect
    2. More transformations!!!!
    3. Modified Java Script Value:
      • Add the following code: var _newId = "{ '$oid': '" + _id + "' }";
      • Set up an output mapping at the bottom.
        • Fieldname: _newId
        • Rename to: _id
        • Replace value 'Fieldname' or 'Rename to': Y

    4. More transformations if desired!!!
    5. MongoDB Output:


    • Set _id up:
      • Use field name: Y
      • NULL values: Ignore
      • JSON: Y <------------------------------------------------ This is the trick!!!!
      • Match field for update: Y <----- tells PDI to use for querying
      • Modifier operatino: N/A

    Now when you look at your field mapping output (press SPACEBAR on the MongoDB Output), you'll see it listed as a JSON Document.

    You should now be good to upsert!

    Environment:

    Mongo (via Docker) 3.2.8, no auth (all for testing purposes)
    PDI version: pdi-ce-6.1.0.1-196

    PS, this is literally the worst forum software I've ever used. There is ZERO formatting....
    Last edited by drewlover; 10-12-2016 at 03:41 PM. Reason: I figured it out!

  3. #3
    Join Date
    Jan 2018
    Posts
    2

    Default

    Thank you!

    I was just googling for this exact situation.

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