auto_created getting ignored by makemigrations

[Joey Espinosa]

Dear Anyone,

I'm having an issue with a ManyToMany "through" table not being recognized by the makemigrations command. Please consider the model definitions at the following pastebin: http://pastebin.ubuntu.com/12011412/

So, I have a Player model. Players are stored and updated in that model (also for clarification, the Player model is in a separate app because it's used for other purposes). The League model, when created, makes available all of the Player objects in the DB for drafting to a LeagueTeam. That's why there's a "through" table for LeaguePlayer, since I don't want to affect the original Player object, and I want to add the additional information as to what LeagueTeam the LeaguePlayer got drafted to (think fantasy football).

However, I'm getting errors in the console about the draft_leagueplayer (the relevant app's name is "draft") table not existing, and I noticed it's not getting created in the db. After a little digging, I realized that ultimately the django.apps.config module's AppConfig.get_models() method is set to ignore any apps with "auto_created = True" by default, thus ignoring LeaguePlayer. If you look at the pastebin above, I am adding Player objects to the League as soon as it's created, and the "auto_created = True" meta attribute helps me do that easily.

I'm wondering if there is a way around this. I need extra information in this Many-to-Many relationship (the team the player is drafted to), and I'm surprised the auto_created attribute exists and doesn't seem to work (since the migration ignores the model). Is this a bug, or should I be manually creating LeaguePlayer objects on-the-fly when adding to the League object instead of using auto_created? Am I misusing auto_created?

Joey "JoeLinux" Espinosa about.me/joelinux

[Markus Holtermann]

Hey Joey,

not settings `auto_created=True` should do.

/Markus

[zubair alam]

Hi Joey.

I was trying to understand your models, relationship and logic behind them.

How you are supposed to create a League object? 

I tried creating as follows.

p=Player.objects.create(name='Shahid Afridi')

l=League(name='FootballDevils')

l.save() // not calling directly objects.create on League as you're checking some boolean in its save method.

and as i expected, it says that you have to create League object via LeaguePlayer intermediary Model, but in LeaguePlayer model you need to pass a League object first.

This might clear what i'm trying to say https://docs.djangoproject.com/en/1.8/topics/db/models/#extra-fields-on-many-to-many-relationships

I will suggest you to not override save method in League model as you want an Intermediary table as well and Django doesn't let you use add method, rather use post_save signal on League object save event and attach all available player objects to newly created league via LeaguePlayer.

I've created a pastebin here for the same. http://paste.ubuntu.com/12015824/

Zubair Alam

[Joey Espinosa]

@zubair: The reason Django complained about wanting to create the LeaguePlayer intermediary model when you used "add()" is because you didn't have auto_created=True. That allows Django to link the objects correctly via the intermediary model automatically without populating any of the extra fields in the relationship. That's exactly what I want, since I don't need to populate "drafted_to" at all until later in the application. I'm just really wondering why auto_created is available as an option if Django is just going to skip that model when creating tables. I'm trying to question whether this is a bug, because I figured if Django is going to give me a straightforward and concise way to do what I want, then I'd rather do that instead of having to resort to more complex solutions. The relationship doesn't work at all if I use auto_created.

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