給一個項目配置多個數據庫，不同app裏的model對應不同的數據庫

settings中的設置

 1 # 設置3個數據庫
 2 
 3 DATABASES = {
 4     ‘users_base‘: {
 5         ‘ENGINE‘: ‘django.db.backends.mysql‘,
 6         "HOST": "127.0.0.1",
 7         "NAME": "thunder_blended_learning",
 8         "PASSWORD": "root",
 9         "USER": "root",
 
10         "PORT": 3306,
11         ‘OPTIONS‘: {‘charset‘: ‘utf8mb4‘},
12     },
13     ‘cms‘: {
14         ‘ENGINE‘: ‘django.db.backends.mysql‘,
15         "HOST": "127.0.0.1",
16         "NAME": "thunder_blended_learning",
17         "PASSWORD": "root",
18         "USER": "root",
19         "
 
PORT": 3306,
20         ‘OPTIONS‘: {‘charset‘: ‘utf8mb4‘},
21     },
22     ‘default‘: {
23         ‘ENGINE‘: ‘django.db.backends.mysql‘,
24         "HOST": "127.0.0.1",
25         "NAME": "xuetangx",
26         "PASSWORD": "root",
27         "USER": "root",
28         "PORT": 3306,
29         ‘
 
OPTIONS‘: {‘charset‘: ‘utf8mb4‘},
30     }
31 }
32 
33 # 不同app可能對應不同的db，註意在本站app: cms，users_base,users_up不允許被migrate
34 DATABASE_ROUTERS = [‘new_xuetangx.app_db_router.UsersBaseDBRouter‘,‘new_xuetangx.app_db_router.CmsDBRouter‘]

app_db_router文件中設置不同的app對應的數據庫的名字，沒有指定數據庫的app用默認的default數據庫

 1 class UsersBaseDBRouter(object):
 2     """
 3     A router to control all database operations on models in the
 4     auth application.
 5     """
 6     def db_for_read(self, model, **hints):
 7         """
 8         Attempts to read auth models go to auth_db.
 9         """
10         if model._meta.app_label == ‘users_base‘:
11             return ‘users_base‘
12         if model._meta.app_label == ‘auth‘:
13             return ‘users_base‘
14         return None
15 
16     def db_for_write(self, model, **hints):
17         """
18         Attempts to write auth models go to auth_db.
19         """
20         if model._meta.app_label == ‘users_base‘:
21             return ‘users_base‘
22         if model._meta.app_label == ‘auth‘:
23             return ‘users_base‘
24         return None
25 
26     def allow_relation(self, obj1, obj2, **hints):
27         """
28         Allow relations if a model in the auth app is involved.
29         """
30         if obj1._meta.app_label == ‘users_base‘ or 31                 obj2._meta.app_label == ‘users_base‘:
32             return True
33         if obj1._meta.app_label == ‘auth‘ or 34                 obj2._meta.app_label == ‘auth‘:
35             return True
36         return None
37     def allow_migrate(self, db, app_label, model_name=None, **hints):
38         """
39         do not allow migrate to users_base‘s db.
40         """
41         if db == ‘users_base‘ or app_label == ‘users_base‘ or app_label == ‘auth‘:
42             return False
43         else:
44             return None
45 
46 
47 class CmsDBRouter(object):
48     """
49     A router to control all database operations on models in the
50     auth application.
51     """
52     def db_for_read(self, model, **hints):
53         """
54         Attempts to read auth models go to auth_db.
55         """
56         if model._meta.app_label == ‘cms‘:
57             return ‘cms‘
58         return None
59 
60     def db_for_write(self, model, **hints):
61         """
62         Attempts to write auth models go to auth_db.
63         """
64         if model._meta.app_label == ‘cms‘:
65             return ‘cms‘
66         return None
67 
68     def allow_relation(self, obj1, obj2, **hints):
69         """
70         Allow relations if a model in the auth app is involved.
71         """
72         if obj1._meta.app_label == ‘cms‘ or 73                 obj2._meta.app_label == ‘cms‘:
74             return True
75         return None
76     def allow_migrate(self, db, app_label, model_name=None, **hints):
77         """
78         do not allow migrate to cms‘s db.
79         """
80         if db == ‘cms‘ or app_label == ‘cms‘:
81             return False
82         else:
83             return None

上述設置表示，app：auth , users_base 使用users_base 數據庫，可讀可寫，可以在app內進行表關聯操作，不可以進行migrate操作

app:cms 使用cms 數據庫，可讀可寫，可以在app內進行表關聯操作，不可以進行migrate操作

其他的app使用default 數據庫

 1 class LmsDBRouter(object):
 2     """
 3     A router to control all database operations on models in the
 4     auth application.
 5     """
 6     def db_for_read(self, model, **hints):
 7         """
 8         Attempts to read auth models go to auth_db.
 9         """
10         if model._meta.app_label == ‘lms‘:
11             return ‘default‘
12         return None
13 
14     def db_for_write(self, model, **hints):
15         """
16         Attempts to write auth models go to auth_db.
17         """
18         if model._meta.app_label == ‘lms‘:
19             return ‘default‘
20         return None
21 
22     def allow_relation(self, obj1, obj2, **hints):
23         """
24         Allow relations if a model in the auth app is involved.
25         """
26         if obj1._meta.app_label == ‘lms‘ or 27                 obj2._meta.app_label == ‘lms‘:
28             return True
29         return None
30     def allow_migrate(self, db, app_label, model_name=None, **hints):
31         """
32         can only migrate lms app. Other app are not allowed to be migrated here
33         """
34         if app_label == ‘lms‘:
35             return db == ‘default‘
36         return False

上述設置表示，app：lms 使用 default 數據庫，可讀可寫，可以在app內進行表關聯操作，可以進行migrate操作

另外若不寫上述lms的配置，也能起到相應的作用，再次寫出僅供學習之用

參考官網：https://docs.djangoproject.com/en/2.1/topics/db/multi-db/

Django項目配置多個數據庫