在SQLAlchemy类中查找所有关联代理 [英] Finding all association proxies in a SQLAlchemy class

问题描述

我知道一种从类A(继承自db.Model的类)中获取所有适当的SQLA列的简便方法-我可以在运行时执行 A .__ table __.columns .但是，A还具有多个关联代理，而且我不知道一种优雅的方式来获取这些关联的列表(除了仅在类的所有属性上运行之外).也许可以使用SQLA的检查方法吗?

I know an easy way to get all proper SQLA columns from a class A (that inherits from db.Model) - I can do A.__table__.columns at runtime. However, A also has several association proxies, and I don't know of an elegant way to get a list of those (other than just running on all of the class' attributes). Is there maybe a way to use SQLA's inspect for this?

我正在使用python 2.7和Flask-SQLAlchemy.

I'm using python 2.7 and Flask-SQLAlchemy.

推荐答案

有一种使用

There is a way using the runtime inspection API. With it you wouldn't even need to poke at the internals of A through __table__:

from sqlalchemy import inspect

inspect(A).columns

例如，有关关联代理的列表，您可以这样做

For a list of association proxies you could for example do

from sqlalchemy.ext.associationproxy import ASSOCIATION_PROXY

proxies = [desc for desc in inspect(A).all_orm_descriptors
           if desc.extension_type is ASSOCIATION_PROXY]

<代码> all_orm_descriptors 是 InspectionAttr 属性的集合，其中包括映射的属性以及扩展声明的属性.要区分扩展名和非扩展名，请检查

all_orm_descriptors is a collection of InspectionAttr attributes, which includes mapped attributes as well as attributes declared by extensions. To differentiate between extensions, and non-extensions, inspect the InspectionAttr.extension_type constant attribute.

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