CODEWITHSUNDEEP
pythongoogle-app-enginegoogle-cloud-platformgoogle-cloud-datastoreapp-engine-ndb
Jimmy Lin
Jimmy Lin

Reputation: 1501

Using keywords argument to query in GAE ndb

I met some problems when I would like to query the ndb on GAE.

Is it possible to query the db using keywords argument?

From the document, it shows that the query string should be expression.

qry = Account.query(username == 'test_user')

Can I query or filter by a keyword argument like

search_userinfo(username='test_user')

def search_userinfo(self, **kwargs):
    return UserInfo.query(**kwargs)

If not, how can I transfer the keyword argument into the expression that match ndb's condition.

Thank you.

Upvotes: 2

Views: 178

Answers (2)

Greg
Greg

Reputation: 10360

Something like this will turn your kwargs into filters for the query:

def search_userinfo(**kwargs):
  qry = UserInfo.query(*(getattr(UserInfo, k)==v for (k,v) in kwargs.items()))
  return qry

Upvotes: 2

Brent Washburne
Brent Washburne

Reputation: 13138

First of all, the query should have the class name before the property name:

qry = Account.query(Account.username == 'test_user')

Next, the query uses the == operator while the **kwargs uses the = operator, so you'll have to write the query out yourself:

def search_userinfo(self, **kwargs):
    return UserInfo.query(UserInfo.username == kwargs['username'])

If you want to query on a list of properties, you could chain them together like this:

def search_userinfo(self, **kwargs):
    qry = UserInfo.query()
    if 'username' in kwargs:
        qry = qry.filter(UserInfo.username == kwargs['username'])
    if 'other' in kwargs:
        qry = qry.filter(UserInfo.other == kwargs['other'])
    ...
    return qry

See NDB Query Class for more details.

Upvotes: 0

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