Django項目配置連接多個數(shù)據庫的方法記錄
一個APP對應一個默認數(shù)據庫,若連接其他數(shù)據庫用".using()"
Author.objects.using('db02').all()
1、在項目settings中增加數(shù)據庫配置
# settings.py
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.oracle',
'NAME': 'orcl19c',
'USER': "username01",
'PASSWORD': "password01",
'HOST': "110.10.1.11",
'PORT': 1511,
},
'db_2': {
'ENGINE': 'django.db.backends.oracle',
'NAME': 'orcl19c',
'USER': "username02",
'PASSWORD': "password02",
'HOST': "120.20.2.22",
'PORT': 1512,
}
}
# 以下MyProject改成項目名,默認default不用修改
DATABASE_ROUTERS = ['MyProject.database_router.DatabaseAppsRouter']
DATABASE_APPS_MAPPING = {
'app01': 'default',
'app02': 'db_2',
}
2、在項目根目錄下Myproject/Myproject 新建數(shù)據庫路由文件database_router.py
直接復制以下代碼,無需修改
from django.conf import settings
DATABASE_MAPPING = settings.DATABASE_APPS_MAPPING
class DatabaseAppsRouter(object):
"""
A router to control all database operations on models for different
databases.
In case an app is not set in settings.DATABASE_APPS_MAPPING, the router
will fallback to the `default` database.
Settings example:
DATABASE_APPS_MAPPING = {'app1': 'db1', 'app2': 'db2'}
"""
def db_for_read(self, model, **hints):
""""Point all read operations to the specific database."""
if model._meta.app_label in DATABASE_MAPPING:
return DATABASE_MAPPING[model._meta.app_label]
return None
def db_for_write(self, model, **hints):
"""Point all write operations to the specific database."""
if model._meta.app_label in DATABASE_MAPPING:
return DATABASE_MAPPING[model._meta.app_label]
return None
def allow_relation(self, obj1, obj2, **hints):
"""Allow any relation between apps that use the same database."""
db_obj1 = DATABASE_MAPPING.get(obj1._meta.app_label)
db_obj2 = DATABASE_MAPPING.get(obj2._meta.app_label)
if db_obj1 and db_obj2:
if db_obj1 == db_obj2:
return True
else:
return False
return None
def allow_syncdb(self, db, model):
"""Make sure that apps only appear in the related database."""
if db in DATABASE_MAPPING.values():
return DATABASE_MAPPING.get(model._meta.app_label) == db
elif model._meta.app_label in DATABASE_MAPPING:
return False
return None
def allow_migrate(self, db, app_label, model=None, **hints):
"""
Make sure the auth app only appears in the 'auth_db'
database.
"""
if db in DATABASE_MAPPING.values():
return DATABASE_MAPPING.get(app_label) == db
elif app_label in DATABASE_MAPPING:
return False
return None
3、使用inspectdb反向生成各app的model類之后,配置model類對應要鏈接的數(shù)據庫
反向生成models.py 命令:
python manage.py inspectdb --database db1 TableName1 > app01/models.py python manage.py inspectdb --database db2 TableName2 > app02/models.py
# 編輯app01下的models.py:
class Names(models.Model): #該model使用default數(shù)據庫
id=models.CharField(primary_key=True,max_length=100, blank=True, null=True)
name=models.CharField(max_length=32,primary_key=True,unique=True)
class Meta:
#app_label = 'app01' #由于該model連接default數(shù)據庫,所以在此無需指定
db_table = 'names'
# 編輯app02下的models.py:
class Classnum(models.Model): #該model使用default數(shù)據庫
id=models.CharField(primary_key=True,max_length=100, blank=True, null=True)
classnum=models.CharField(max_length=32,primary_key=True,unique=True)
class Meta:
app_label = 'app02'
db_table = 'classnum'
4、同步數(shù)據庫
# 同步default節(jié)點數(shù)據庫,只運行不帶 --database參數(shù)的命令,不對其他數(shù)據庫進行同步 python manage.py makemigrations python manage.py migrate # 同步db02節(jié)點數(shù)據庫: python manage.py makemigrations python manage.py migrate --database=db02
5、若要連接配置外的數(shù)據庫
Author.objects.using('other').all()
my_object.save(using='legacy_users')
my_object.delete(using='legacy_users')
移動對象到另一個數(shù)據庫時會發(fā)生主鍵沖突,可以使用obj.pk方法清除主鍵再保存對象
>>> p = Person(name='Fred') >>> p.save(using='first') >>> p.pk = None # Clear the primary key. >>> p.save(using='second') # Write a
總結
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