Basic 103 Quizz about JOIN

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Vincent74
Vincent74 Registered Posts: 2 ✭✭✭

hello, I failed to answer the question 2 of the Quizz. Could you help me understand the correct answer ?

It says :

Q : When choosing columns from two datasets to serve as the join key in a Join recipe, which of the following must be the same for each column?

R : The storage type of the columns (unless auto cast has been enabled)

By storage type, do you mean type of the data of each column ...string / string , date / date, for instance ?

Best Answer

  • Ignacio_Toledo
    Ignacio_Toledo Dataiku DSS Core Designer, Dataiku DSS Core Concepts, Neuron 2020, Neuron, Registered, Dataiku Frontrunner Awards 2021 Finalist, Neuron 2021, Neuron 2022, Frontrunner 2022 Finalist, Frontrunner 2022 Winner, Dataiku Frontrunner Awards 2021 Participant, Frontrunner 2022 Participant, Neuron 2023 Posts: 411 Neuron
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    Hi @Vincent74
    ,

    Each column in a Dataiku dataset has both a "storage type" and a "meaning" as it can be seen in this example screenshot:

    Selection_012.png

     Storage type can be interpreted as the "data type" in the source database or source file to which the dataset is connected to.

    The idea of the question is to understand that doing a join using two columns that have the same meaning but different storage type wouldn't work: what matters is that the "storage type" is the same in both columns.

    Hope this helps!

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