How to achieve multi-databases queries

[larryhq]

My software environment ：
python3.4.2 Django:1.7.1 django-haystack:2.3.1
I know how to config multi haystack collections in my project
and know how to config multi databases in my django
but when i use haystack search my data , how to achieve full search.
Thers are lots of databases in my project,but when i search data use haystack ,it seach only defaut database every time . How to achieve multi databases queries?
Thanks .

[dwickwire]

Can you import the model from the other DB that you need access to and use that model in your index?

[larryhq]

My DB config in django is like this：

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': '{}_default'.format(PROJECT_NAME),
        'USER': 'root'
    }
}

DB_MOD = 4
for i in range(DB_MOD):
    db_dict = DATABASES['default'].copy()
    db_dict['NAME'] = '{}_{}'.format(PROJECT_NAME, i)
    DATABASES['db_{}'.format(i)] = db_dict

There are five databases in my project and all of the databases has the same fabric。
In Django use using(db) method can choose the database which i want. but I don't know when I use haystack ,how to choose the database which i want. The search engine I used is solr4.10.2,the config is

HAYSTACK_CONNECTIONS = {
    'default': {
        'ENGINE': 'haystack.backends.solr_backend.SolrEngine',
        'URL': 'http://127.0.0.1:8983/solr'
        # ...or for multicore...
        # 'URL': 'http://127.0.0.1:8983/solr/mysite',
    }
}

Now I want to search data from all databases, How to config , And Is it support like this?

[Bearbobs]

following. having same issue