class Field:
def __init__(self,name,column_type,primary_key,defaule):
self.name = name
self.column_type = column_type
self.primary_key = primary_key
self.default = defaule
class IntegerField(Field):
def __init__(self,name,column_type = 'int',primary_key = False,default = 0):
super().__init__(name,column_type,primary_key ,default )
class StringField(Field):
def __init__(self,name,column_type = 'varchar(64)',primary_key = False,default = None):
super().__init__(name,column_type,primary_key ,default )
class OrmMetaClass(type):
def __new__(cls, class_name,class_bases,class_attr):
if class_name == 'Models':
return type. __new__(cls, class_name,class_bases,class_attr)
table_name = class_attr.get('table_name',class_name)
primary_key = None
mappings = {}
for k,v in class_attr.items():
if isinstance(v,Field):
mappings[k] = v
if v.primary_key:
if primary_key:
raise TypeError('only need one primary key')
primary_key = v.primary_key
for k in mappings:
class_attr.pop(k)
if not primary_key:
raise TypeError('a primary key is necessary')
class_attr['primary_key'] = primary_key
class_attr['table_name'] = table_name
class_attr['mappings'] = mappings
return type.__new__(cls, class_name,class_bases,class_attr)
class Models(dict,metaclass=OrmMetaClass):
def __init__(self,**kwargs):
super().__init__(**kwargs)
def __getattr__(self, item):
return self.get(item)
def __setattr__(self, key, value):
self[key] = value
class User(Models):
user_id = IntegerField(name = 'user_id',primary_key=True)
user_name = StringField(name = 'user_name',)
user_pwd = StringField(name = 'user_pwd')
if __name__ == '__main__':
user = User()
user.name = 'agsol'
user.id = 1
user.pwd = '123'
print(user)
print(user.name)
