CODEWITHSUNDEEP
pythongoogle-app-enginegoogle-cloud-datastoreapp-engine-ndb
Napolean
Napolean

Reputation: 5543

NDB query using filters on Structured property which is also repeated ?

I am creating a sample application storing user detail along with its class information.

Modal classes being used are :

Model class for saving user's class data

class MyData(ndb.Model):
    subject =  ndb.StringProperty()
    teacher = ndb.StringProperty()
    strength = ndb.IntegerProperty()
    date = ndb.DateTimeProperty()

Model class for user

class MyUser(ndb.Model):
    user_name = ndb.StringProperty()
    email_id = ndb.StringProperty()
    my_data = ndb.StructuredProperty(MyData, repeated = True)

I am able to successfully store data into the datastore and can also make simple query on the MyUser entity using some filters based on email_id and user_name.

But when I try to query MyUser result using filter on a property from the MyUser modal's Structured property that is my_data, its not giving correct result.

I think I am querying incorrectly. Here is my query function

function to query based upon the repeated structure property

def queryMyUserWithStructuredPropertyFilter():
    shail_users_query = MyUser.query(ndb.AND(MyUser.email_id == "[email protected]", MyUser.my_data.strength > 30))
    shail_users_list = shail_users_query.fetch(10)

    maindatalist=[]

    for each_user in shail_users_list:
        logging.info('NEW QUERY :: The user details are : %s %s'% (each_user.user_name, each_user.email_id))

    # Class data
        myData = each_user.my_data
        for each_my_data in myData:
            templist = [each_my_data.strength, str(each_my_data.date)]
            maindatalist.append(templist)

            logging.info('NEW QUERY :: The class data is : %s %s %s %s'% (each_my_data.subject, each_my_data.teacher, str(each_my_data.strength),str(each_my_data.date)))

    return maindatalist

I want to fetch that entity with repeated Structured property (my_data) should be a list which has strength > 30.

Please help me in knowing where I am doing wrong.

Thanks.

Upvotes: 1

Views: 2245

Answers (1)

marianosimone
marianosimone

Reputation: 3606

Queries over StructuredProperties return objects for which at least one of the structured ones satisfies the conditions. If you want to filter those properties, you'll have to do it afterwards.

Something like this should do the trick:

def queryMyUserWithStructuredPropertyFilter():
    shail_users_query = MyUser.query(MyUser.email_id == "[email protected]", MyUser.my_data.strength > 30)
    shail_users_list = shail_users_query.fetch(10)

    # Here, shail_users_list has at most 10 users with email being
    # '[email protected]' and at least one element in my_data
    # with strength > 30

    maindatalist = [
        [[data.strength, str(data.date)] for data in user.my_data if data.strength > 30] for user in shail_users_list
    ]

    # Now in maindatalist you have ONLY those my_data with strength > 30
    return maindatalist

Upvotes: 2

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