Puede usar el atributo _meta
del modelo para obtener el objeto de campo y desde el campo puede obtener una relación y mucho más, p. considere una tabla de empleados que tiene una clave externa a una tabla departamento
In [1]: from django.db import models
In [2]: model = models.get_model('timeapp', 'Employee')
In [3]: dep_field = model._meta.get_field_by_name('department')
In [4]: dep_field[0].rel.field_name
Out[4]: 'id'
In [5]: dep_field[0].rel.to
Out[5]: <class 'timesite.timeapp.models.Department'>
de django/db/modelos/options.py
def get_field_by_name(self, name):
"""
Returns the (field_object, model, direct, m2m), where field_object is
the Field instance for the given name, model is the model containing
this field (None for local fields), direct is True if the field exists
on this model, and m2m is True for many-to-many relations. When
'direct' is False, 'field_object' is the corresponding RelatedObject
for this field (since the field doesn't have an instance associated
with it).
Uses a cache internally, so after the first access, this is very fast.
"""
Buena pregunta. Esto me salvó el culo – GabiMe