在mongodb中存储对象值

Question

我在python中得到了一些对象值，我想将它们存储在mongodb中以供以后使用，但是运气不好

def callPylink(self):
    from pylinkgrammar.linkgrammar import Parser
    import sys
    p = Parser()
    linkage = p.parse_sent("When was Gandhi born")
    try:
        print "Linkage 0 ", linkage[0]
    except:
        print "error"
    self.collection.insert(linkage[0].__dict__)

在插入行：

^{pr2}$

在mongo中存储python对象的另一种方法是什么。在

更新

    pickled = pickle.dumps(linkage[0])
    self.collection.insert(pickled)

给出错误：

  File "objmongo.py", line 30, in <module>
    data = obj.callPylink()
  File "objmongo.py", line 25, in callPylink
    self.collection.insert(pickled)
  File "/usr/local/lib/python2.7/dist-packages/pymongo/collection.py", line 409, in insert
    gen(), check_keys, self.uuid_subtype, client)
  File "/usr/local/lib/python2.7/dist-packages/pymongo/collection.py", line 386, in gen
    doc['_id'] = ObjectId()
TypeError: 'str' object does not support item assignment

Answer 1

要在mongodb中存储字典，您的字典只能包含字符串键和mongodb可以序列化（编码）的那些类型的值。这里不是这样。在

您可以将复杂的对象树序列化为字节字符串并使用^{}模块反序列化它们，使用pickle.dumps(obj)将对象序列化为bytestring，使用pickle.loads(bytestring)来反序列化对象

示例：给定以下类和实例

>>> class OurClass():
...     def __init__(self, arg):
...         self.arg = arg
... 
>>> instance = OurClass(42)

我们导入pickle模块

^{pr2}$

pickled是要存储到数据库中文档字段中的值，例如：

my_doc = { 'linkage': pickled }
self.collection.insert(my_doc)

现在可以使用pickle.loads恢复原始值

>>> restored = pickle.loads(pickled)
>>> restored
<__main__.OurClass object at 0x7fc91cb35cf8>
>>> restored.arg
42