Question

I have a MySQL database with a table called sources, there I have two columns called srctype and url where srctype is a name (e.g: Hello) and url is an url (e.g: http://google.com)

In Python using SQLAlchemy, I could filter the srctype and get a list of the urls, for example;

src = "hello"    
links = session.query(sources).filter_by(srctype=src).all()

Easy, now I am migrating this data to a MongoDB, for this I am using pymongo.

I have a function where it saves the srctype and url to mongodb’s database

    def insertSources(self, srctype, link):
        """ Insert rss sources so we can parse them """
        new = {srctype: link}
        self.__sources.insert(new)

and a function that retrieves the srctype

 def getSources(self, type=None, single=True): # type == srctype
    if type:
        if single:
            return self.__sources.find_one()
        else:
            return iter(self.__sources.find({srctype:type}))
    else:
        if single:
            return self.__sources.find_one()
        else:
            return iter(self.__sources.find())

The problem here is, since there is no column called srctype and no column called url, how can I do the same as the SQLAlchemy/MySQL example?

In MySQL would be;

SELECT * FROM sources WHERE srctype="hello"

I wonder how will that be in the retrieve function I have (also in the insert function, since I am not sure if what I did there is correct for the job I want). In the insertSources function I simple add a dict to MongoDB, clearly I won’t be able to get the srctype in the getSources function, since srctype in MongoDB is no column.
Any help would be great.

Answer 1

Your problem is that you are not setting the name correctly when saving the data. Instead of

def insertSources(self, srctype, link):
    """ Insert rss sources so we can parse them """
    new = {srctype: link}
    self.__sources.insert(new)

You should do

def insertSources(self, srctype, link):
    """ Insert rss sources so we can parse them """
    new = {'srctype': srctype, 'link': link}
    self.__sources.insert(new)

And similarly in getSources(). If srctype is passed, find() and find_one() should receive {'srctype': type}.