Single Django App Using Two Databases

Question

How can I configure models in Django which are being hosted in two different databases?

So far, I have 3 databases set up within my great Django environment. One of my apps uses a Router to automatically send data to the correct database -- this is easily done since this app only deals with that one database.

However, I have another app that uses two different databases. The app "controls" one of them, but gets data from a second that is updated through another application entirely.

I have tried adding an arbitrary attribute to the model's Meta class, to match against in the router, but this is not allowed in Django (as I discovered).

What data can I provide the model that can be matched against in the router, to know which database to go to?

I haven't tested this exact situation, but if you know when defining your model class which DB you want to use, you can set an arbitrary attribute to the class itself rather than its Meta class. — Peter DeGlopper
– Peter DeGlopper, Commented May 15, 2013 at 19:53
I've tried setting a db_name attribute within the regular model, but not all models have the attribute (and system models can't be forced to have it). My router chokes when it reaches these, despite my attempts to verify the attributes existence. In this case, how to a verify the attribute that might not be defined? — Nicholas Pappas
– Nicholas Pappas, Commented May 15, 2013 at 19:59
You could use hasattr to check, or just try/except and catch the exception. — Peter DeGlopper
– Peter DeGlopper, Commented May 15, 2013 at 20:02

Peter DeGlopper · Accepted Answer · 2013-05-15 20:08:55Z

1

If you know when defining your model class which DB you want to use, you can add an arbitrary attribute to the class itself rather than its Meta class. In the router, you can then use hasattr to see if the attribute exists (since it won't for built in models), or just try/except and catch the exception.

answered May 15, 2013 at 20:08

Peter DeGlopper

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