id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
28514	Clarify docs regarding idempotence of RelatedManager.add()	Дилян Палаузов	Jezeniel Zapanta	"At https://docs.djangoproject.com/en/1.11/topics/db/examples/many_to_many/ it's written:
{{{
>> a2.publications.add(p3)
>
> Adding a second time is OK:
> 
>> a2.publications.add(p3)
}}}
Please rephrase it to ""Adding a second time is OK, it doesn't duplicate the relation"".

At https://docs.djangoproject.com/en/1.11/ref/models/relations/ it's written:
{{{
 add(*objs, bulk=True)
 Adds the specified model objects to the related object set.
}}}
Please amend: ""Inserting existing relations this way does not cause problems.""

The purpose of the changes is to make clear, that `add()` is idempotent and it is not necessary first to read the data from the database, join with the new values and eventually write the resulting set back."	Cleanup/optimization	closed	Documentation	1.11	Normal	fixed			Accepted	1	0	0	1	1	0