def update_by_ma(self, schema, instance, commit=True):
"""根据marshmallow以及SQLa实例更新
:param schema: Schema Schema类或实例
:param instance: object Model对象
:param commit: bool 是否commit
此方法用以更新Sqla实例的字段，基于一个marshmallow类或实例，
根据marshmallow类的load字段加载。由于需要一个临时变量的
instance，对于需要同时处理复杂relationship的子关系需要增
加指定active_history=True来跟踪变化以维持正确的加载。
形如：
>>> class Remote(Model):
id = Column(Integer(), primary_key=True)
name = Column(String(80))
>>> class Local(Model):
id = Column(Integer(), primary_key=True)
remote_id = Column(Integer())
remote = relationship("Remote", active_history=True,
backref=backref('local', active_history=True)
)
在这里需要修改Remote中name以及关系时。
"""
from sqlalchemy.orm.attributes import (
get_attribute,
del_attribute,
set_attribute,
)
from marshmallow import Schema
if not isinstance(schema, Schema):
schema = schema()
db.session.add(instance)
loadable_fields = [
k for k, v in schema.fields.items() if not v.dump_only
]
with db.session.no_autoflush:
for field in loadable_fields:
set_attribute(self, field, get_attribute(instance, field))
del_attribute(instance, field)
db.session.expunge(instance)
self.save(commit)
def __delattr__(self, key):
if is_instrumented(self, key):
del_attribute(self, key)
else:
del self._goofy_dict[key]
def __delattr__(self, key):
if is_instrumented(self, key):
del_attribute(self, key)
else:
del self._goofy_dict[key]
def _setattr_from_instance(self, fields: List[str], instance: db.Model):
with db.session.no_autoflush:
for field in fields:
set_attribute(self, field, get_attribute(instance, field))
del_attribute(instance, field)
def _setattr_from_instance(self, fields: List[str], instance: _M) -> None:
with self.session().no_autoflush:
for field in fields:
set_attribute(self.instance(), field, get_attribute(instance, field))
del_attribute(instance, field)
