Basic 103 Quizz about JOIN

[Vincent74]

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 ?

[Ignacio_Toledo · Accepted solution]

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:

 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!

[Vincent74]

thanks ! it's clear now