ruby - The difference in Class.where(id: '1234') and Class.find_by id: '1234' -


I just came across a subtle difference between .where and .find_by < apparently . returns only _id of an object, while .find_by gives a hash. I can explain the difference between the two methods in Railway 4 and Mongoad. ?

Thank you in advance

Please read.

Obtaining an object from a database

To retrieve the object from the database, the active record provides several finder methods

The methods are: < / P>

... cutting ...

  • Where

    • All the above methods ActiveRecord :: Relation return an example.

    Therefore the result of calling class.where (...) is a collection of objects.

    and:

    1.15 find_by

    According to the method find_by finds some conditions first record match example For: 

      client.fund_first_name: 'lipo' # = & gt; # & Lt; Client ID: 1, first_name: "lipo" & gt; Client.Fund_FirstName: 'John' # = & gt; Zero

    (emphasis my)

    then the result of calling class.find_by (...) is the first thing found .


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