database-relations
Cascade delete in Ruby ActiveRecord models?
Yes. On a Rails’ model association you can specify the :dependent option, which can take one of the following three forms: :destroy/:destroy_all The associated objects are destroyed alongside this object by calling their destroy method :delete/:delete_all All associated objects are destroyed immediately without calling their :destroy method :nullify All associated objects’ foreign keys are set … Read more
Relations on composite keys using sqlalchemy
The problem is that you have defined each of the dependent columns as foreign keys separately, when that’s not really what you intend, you of course want a composite foreign key. Sqlalchemy is responding to this by saying (in a not very clear way), that it cannot guess which foreign key to use (firstName or … Read more
How do you track record relations in NoSQL?
All the answers for how to store many-to-many associations in the “NoSQL way” reduce to the same thing: storing data redundantly. In NoSQL, you don’t design your database based on the relationships between data entities. You design your database based on the queries you will run against it. Use the same criteria you would use … Read more
Rails: Using build with a has_one association in rails
The build method signature is different for has_one and has_many associations. class User < ActiveRecord::Base has_one :profile has_many :messages end The build syntax for has_many association: user.messages.build The build syntax for has_one association: user.build_profile # this will work user.profile.build # this will throw error Read the has_one association documentation for more details.
How to express a One-To-Many relationship in Django?
To handle One-To-Many relationships in Django you need to use ForeignKey. The documentation on ForeignKey is very comprehensive and should answer all the questions you have: https://docs.djangoproject.com/en/3.2/ref/models/fields/#foreignkey The current structure in your example allows each Dude to have one number, and each number to belong to multiple Dudes (same with Business). If you want the … Read more