DynamoDB Dynomite Has One
Example:
app/models/user.rb
class User < ApplicationItem
has_one :profile
end
There is typically a corresponding belongs_to as the inverse relationship.
app/models/profile.rb
class Profile < ApplicationItem
belongs_to :user
end
Note: For the test data set below, the id are set to friendly names to help explain. Here’s how to create the Test Data Set.
When both regular and inverse relationships are defined, Dynomite will update both “foreign key” fields.
Creating
user = User.find("bob")
user.profile = Profile.find("profile-bob")
user.profile.id # profile-bob
# The inverse relationship is created
Profile.find("profile-bob").user.id # bob
This will store the ids in the users.profile_id and profiles.user_id fields as String types.
Deleting
There’s no delete method on a single association like has_one. This is because the user.profile returns a Profile model instance. If you delete the like so:
user = User.find("bob")
user.profile.delete # you're deleting the Profile!
Instead, you disassociate by assigning the has_one relationship to nil.
Disassocating
user = User.find("bob")
user.profile = nil
This will disassociate both sides of the relationship if both have been set up.
user.profile # nil
profile = Profile.find("profile-bob")
profile.user # nil