Question

Given embedded one to one mongoid doc, I can’t really get the difference between building and creating actions.

Here what they state:

building and creating

From the parent side, documents in the embedded child can be initialized or created using the specially defined methods.

# Create a new child name given the provided attributes.
person.build_name(vorname: "Heinrich", nachname: "Heine")

# Create a persisted child name.
person.create_name(vorname: "Heinrich", nachname: "Heine")

… can anyone enlight the diff ?
Thanks in advance
luca

Answer 1

When you call create_name, you’re saving the embedded object to the server. When you call build_name you’re just initializing the embedded model, you still need to call save.

This only applies if the parent document has been saved to the server already, otherwise create_name functions exactly like build_name.

For example:

person = Person.first
person.build_name(vorname: "Foo", nachname: "Bar")
person.name.save

and

person = Person.first
person.create_name(vorname: "Foo", nachname: "Bar")

Are the same thing.