Django可以很好地自动序列化从DB返回到JSON格式的ORM模型。

如何序列化SQLAlchemy查询结果为JSON格式?

我试过jsonpickle。编码,但它编码查询对象本身。 我尝试了json.dumps(items),但它返回

TypeError: <Product('3', 'some name', 'some desc')> is not JSON serializable

将SQLAlchemy ORM对象序列化为JSON /XML真的那么难吗?它没有任何默认序列化器吗?现在序列化ORM查询结果是非常常见的任务。

我所需要的只是返回SQLAlchemy查询结果的JSON或XML数据表示。

需要在javascript datagird中使用JSON/XML格式的SQLAlchemy对象查询结果(JQGrid http://www.trirand.com/blog/)


当前回答

2023年末

我的实现

def obj_to_dict(obj, remove=['_sa_instance_state'], debug=False):
    result = {}

    if type(obj).__name__ == "Row":
        return dict(obj)

    obj = obj.__dict__
    for key in obj:
        if key in remove:
            continue

        result[key] = obj[key]

    if debug:
        print(result)

    return result

其他回答

step1:
class CNAME:
   ...
   def as_dict(self):
       return {item.name: getattr(self, item.name) for item in self.__table__.columns}

step2:
list = []
for data in session.query(CNAME).all():
    list.append(data.as_dict())

step3:
return jsonify(list)

经过一番尝试,我想出了自己的解决方案

def to_dict(self):
    keys = self.__mapper__.attrs.keys()
    attrs = vars(self)
    return { k : attrs[k]  for k in keys}

你可以把你的对象输出为一个字典:

class User:
   def as_dict(self):
       return {c.name: getattr(self, c.name) for c in self.__table__.columns}

然后使用User.as_dict()序列化对象。

如将sqlalchemy行对象转换为python dict中所述

这并不是那么简单。我写了一些代码来做这件事。我还在开发中,它使用了MochiKit框架。它基本上使用代理和注册的JSON转换器在Python和Javascript之间转换复合对象。

数据库对象的浏览器端是db.js 它需要proxy.js中的基本Python代理源代码。

在Python方面,有基本代理模块。 最后是webserver.py中的SqlAlchemy对象编码器。 它还依赖于models.py文件中的元数据提取器。

下面是一个解决方案,它允许您选择希望在输出中包含的关系。 注意:这是一个完整的重写,将dict/str作为一个参数,而不是一个列表。修复了一些东西..

def deep_dict(self, relations={}):
    """Output a dict of an SA object recursing as deep as you want.

    Takes one argument, relations which is a dictionary of relations we'd
    like to pull out. The relations dict items can be a single relation
    name or deeper relation names connected by sub dicts

    Example:
        Say we have a Person object with a family relationship
            person.deep_dict(relations={'family':None})
        Say the family object has homes as a relation then we can do
            person.deep_dict(relations={'family':{'homes':None}})
            OR
            person.deep_dict(relations={'family':'homes'})
        Say homes has a relation like rooms you can do
            person.deep_dict(relations={'family':{'homes':'rooms'}})
            and so on...
    """
    mydict =  dict((c, str(a)) for c, a in
                    self.__dict__.items() if c != '_sa_instance_state')
    if not relations:
        # just return ourselves
        return mydict

    # otherwise we need to go deeper
    if not isinstance(relations, dict) and not isinstance(relations, str):
        raise Exception("relations should be a dict, it is of type {}".format(type(relations)))

    # got here so check and handle if we were passed a dict
    if isinstance(relations, dict):
        # we were passed deeper info
        for left, right in relations.items():
            myrel = getattr(self, left)
            if isinstance(myrel, list):
                mydict[left] = [rel.deep_dict(relations=right) for rel in myrel]
            else:
                mydict[left] = myrel.deep_dict(relations=right)
    # if we get here check and handle if we were passed a string
    elif isinstance(relations, str):
        # passed a single item
        myrel = getattr(self, relations)
        left = relations
        if isinstance(myrel, list):
            mydict[left] = [rel.deep_dict(relations=None)
                                 for rel in myrel]
        else:
            mydict[left] = myrel.deep_dict(relations=None)

    return mydict

举个关于person/family/homes/rooms的例子…把它转换成json,你只需要

json.dumps(person.deep_dict(relations={'family':{'homes':'rooms'}}))