单个Django模型,多个表? [英] Single Django model, multiple tables?
问题描述
我相信,您可以制作一个返回模型的工厂函数动态 db_table 。
def getModel(db_table):
class MyClass(models.Model):
#像往常一样定义
class Meta:
db_table = db_table
返回MyClass
newClass = getModel('29345794_table')
newClass.objects.filter(...
编辑:Django不会创建类的新实例 _meta
属性每次调用此函数时,为 _meta
创建一个新实例,它取决于类的名称(Django必须在某处缓存),可以使用元类在运行时更改类的名称:
def getModel(db_table):
class MyClassMetacla ss(models.base.ModelBase):
def __new __(cls,name,bases,attrs):
name + = db_table
return models.base.ModelBase .__ new __(cls,name, base,attrs)
class MyClass(models.Model):
__metaclass__ = MyClassMetaclass
class Meta:
db_table = db_table
返回MyClass
不知道是否可以在已定义的动态类。我没有这样做,但它可能会工作。
您可以随时设置。
>>> MyModel._meta.db_table ='10293847_table'
>>> MyModel.objects.all()
I have several temporary tables in a MySQL database that share the same schema and have dynamic names. How would I use Django to interface with those tables? Can a single model draw data from multiple tables?
You could, I believe, make a factory function that would return your model with a dynamic db_table.
def getModel(db_table):
class MyClass(models.Model):
# define as usual ...
class Meta:
db_table = db_table
return MyClass
newClass = getModel('29345794_table')
newClass.objects.filter( ...
EDIT: Django does not create a new instance of the class's _meta
attribute each time this function is called. Creating a new instance for _meta
it is dependent upon the name of the class (Django must cache it somewhere). A metaclass can be used to change the name of the class at runtime:
def getModel(db_table):
class MyClassMetaclass(models.base.ModelBase):
def __new__(cls, name, bases, attrs):
name += db_table
return models.base.ModelBase.__new__(cls, name, bases, attrs)
class MyClass(models.Model):
__metaclass__ = MyClassMetaclass
class Meta:
db_table = db_table
return MyClass
not sure if it can be set dynamically on an already-defined class. I haven't done this myself but it might work.
You can set this whenever.
>>> MyModel._meta.db_table = '10293847_table'
>>> MyModel.objects.all()
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