Django model's relationships and fetching (or excluding) related data from database

I'm having a hard time finding a decent explanation about this in django's official documentation, so I'll ask my question here.

in django 5.0 if two models have a relationship (let's call them Model1 and Model2) with whether a OneToOneField, ForeignKey or ManyToManyField , when you fetch some objects from the database with a query like this :

data = Model1.objects.filter(field1=value)

do the Model2 objects related to the objects in data (which are of the type Model1) get fetched and joined to the queryset automatically?

if the answer to my question is YES, I wanna know how to exclude some related data from the queryset and if the answer is NO, I wanna know how to include them in the queryset.

note that the relationship might be of any type (one-to-one , many-to-one, many-to-many) and can be a reverse or forward relationship. if the answer to my question depends on the type of relationship between two objects, please explain all the possible cases.

if you know where exactly I can read about this, please leave me a link.

I've tried asking a bunch of AIs about this but they just confused me with contradictory answers.

do the Model2 objects related to the objects in data (which are of the type Model1) get fetched and joined to the queryset automatically?

No, but it is not complicated to do so, work with .select_related(…) ^[Django-doc]:

Model1.objects.filter(field1=value).select_related('my_field_name')

where my_field_name is either the name of the ForeignKey or OneToOneField, or the related_name ^[Django-doc] of a OneToOneField.

If you want to work with ManyToManyFields or reverse ForeignKeys, then using a JOIN would be bad query design: it means the same column values will be repeated for Model1 for as much related Model2s there are. In that case .prefetch_related(…) ^[Django-doc] is used, which will make an extra query to fetch all related items of all the items in the first queryset, and thus minimizing bandwidth between the database and the Django application:

Model1.objects.filter(field1=value).select_related('my_m2m_field_name')

You can also use this for (reversed) OneToOneFields and ForeignKeys.

I've tried asking a bunch of AIs about this but they just confused me with contradictory answers.

Chatbots are essentially a word predictator: it detedrmines what is the most likely next word with a given context. As a result asking the same question generates different answers, and slight changes in the question can also trigger totally different answers.