python - Django - ManyToMany relation without the cross table -

i have 2 models: city , service. each city record can contain many services , each service can linked each city.

class city(models.model):     name = models.charfield(max_length=255, unique=true)  class service(models.model):     name = models.charfield(max_length=255, unique=true)  class cityservice(models.model):     city = models.foreignkey(city)     service = models.manytomanyfield(service) 

i use manytomanyfield enable multiple selections in django admin. django creates 1 more table store m2m relations..

is possible configure django models reach following table structure:

+----+---------------+------------+ | id | city_id       | service_id | +----+---------------+------------+ |  1 |             1 |         1  | |  2 |             1 |         2  | |  3 |             2 |         3  | +----+---------------+------------+ 

why not use structure like:

class service(models.model):     name = models.charfield(max_length=255, unique=true)  class city(models.model):     name = models.charfield(max_length=255, unique=true)     service = models.manytomanyfield(service)