Multi-database in Django

Question

I'm trying to setup many databases in my Django project. This my settings.py :

    DATABASES = {
    'default': {
        'ENGINE': 'django.contrib.gis.db.backends.postgis',
        'NAME': 'portail',
        'USER': 'postgres',
        'PASSWORD': '',
        'HOST': '',
        'PORT': '',
    },
    'osm': {
        'ENGINE': 'django.contrib.gis.db.backends.postgis',
        'NAME': 'osm', 
        'USER': 'postgres',
        'PASSWORD': '',
        'HOST': '',
        'PORT': '',
    }
}

DATABASE_ROUTERS = ['portail.router.dbrouter']

I know, I'm using postgres user. It's dev.

And I have this router.py in portail folder :

class dbrouter(object): 
    def db_for_read(self, model, **hints):
        if model._meta.app_label == 'api':
            return 'osm'
        return 'default'

If I try to get :

http://127.0.0.1:8000/api/way/96300215

I have an error, my table does not exist. I suppose that it can't determine which DB.

I know that my router is executed. It's very strange, if I switch my 2 databases "portail" and "osm" with the same name in django (default and osm) it still doesn't work. And I know that Django is going into the "if".

After some comments, I give you my view :

def getObject(request,type,id,format):

    if type == "node":
        osmObject = get_object_or_404(PlanetOsmPoint,osm_id=id)    

    if type == "way" or type == "relation":
        if type == "relation":
            id = int(id) * -1

        #Un way|relation peut-être dans la table line ou polygon, il faut tester avec un union et récuperer le type de géometrie
        cursor = connection.cursor()
        cursor.execute('SELECT ST_GeometryType(way) FROM planet_osm_line WHERE osm_id= %s UNION SELECT ST_GeometryType(way) FROM planet_osm_polygon WHERE osm_id= %s',[id,id])

        #Si plusieurs résultats, erreur !
        if cursor.rowcount != 1:
            print cursor.rowcount
            raise Http404

    osmType = cursor.fetchone()

        if osmType[0] == u'ST_Polygon':
            osmObject = get_object_or_404(PlanetOsmPolygon,osm_id=id)
        elif osmType[0] == u'ST_LineString':
            osmObject = get_object_or_404(PlanetOsmLine,osm_id=id)
        else:
            raise Http404


    if format == '' or format == "geojson" or format == "json":
        return HttpResponse(osmObject.way.geojson, content_type="application/json")

One of my model (PlanetOsmLine, PlanetOsmPoint or PlanetOsmPolygon are the same) :

class PlanetOsmLine(models.Model):
    osm_id = models.BigIntegerField(primary_key=True)
    school_cm = models.TextField(db_column='school:CM', blank=True) # Field name made lowercase. Field renamed to remove unsuitable characters.
    access = models.TextField(blank=True)
    addr_housename = models.TextField(db_column='addr:housename', blank=True) # Field renamed to remove unsuitable characters.
    addr_housenumber = models.TextField(db_column='addr:housenumber', blank=True) # Field renamed to remove unsuitable characters.
    addr_interpolation = models.TextField(db_column='addr:interpolation', blank=True) # Field renamed to remove unsuitable characters.
    admin_level = models.TextField(blank=True)
    aerialway = models.TextField(blank=True)
    aeroway = models.TextField(blank=True)
    amenity = models.TextField(blank=True)
    #Some other fields, the list is quite long
    wetland = models.TextField(blank=True)
    width = models.TextField(blank=True)
    wood = models.TextField(blank=True)
    z_order = models.IntegerField(null=True, blank=True)
    way_area = models.FloatField(null=True, blank=True)

    #way = models.LineStringField(blank=True,srid=3857) # This field type is a guess.
    way = models.GeometryField(blank=True,srid=3857) # This field type is a guess.
    objects = models.GeoManager()

    def __unicode__(self):
        return str(self.osm_id)

    class Meta:
        db_table = 'planet_osm_line'
        verbose_name_plural = "planet_osm_line"
        managed = False

Regards

Answer 1

I solved my problem. It was with the cursor connection. In my view, I add :

from django.db import connections
#cursor = connection.cursor()
cursor = connections['osm'].cursor()

Now, the connection know the database. My router is useless in this case.

Source : https://docs.djangoproject.com/en/dev/topics/db/sql/#executing-custom-sql-directly