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	Documentating idempotence of Many2ManyField.add()	Дилян Палаузов	nobody	"At https://docs.djangoproject.com/en/1.11/topics/db/examples/many_to_many/ is 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/ is 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	new	Documentation	1.11	Normal				Unreviewed	0	0	0	0	0	0