CODEWITHSUNDEEP
google-app-enginegoogle-cloud-datastore
neurino
neurino

Reputation: 12445

GAE datastore: filter by date interval

I have this model:

class Vehicle(db.Model):
    ...
    start_production_date = db.DateProperty()
    end_production_date = db.DateProperty()

I need to filter, for example, all vehicles in production within, say, 2010:

I thought I could do:

q = (Vehicle.all()
    .filter('start_production_date >=', datetime(2010, 1, 1))
    .filter('end_production_date <', datetime(2011, 1, 1)))

buy I get BadFilterError:

BadFilterError: invalid filter: Only one property per query may have inequality filters (<=, >=, <, >)..

so, how do I acheive this? Moreover this seems to me a quite common task.

Upvotes: 2

Views: 977

Answers (2)

neurino
neurino

Reputation: 12445

I went with this solution:

I set in model a ListProperty item containing all years the model was crafted:

vhl.production_years = range(start_production_date.year, end_production_date + 1)

Then test:

q = (Vehicle.all()
    .filter('production_years =', 2010))

Upvotes: 2

Lipis
Lipis

Reputation: 21835

One approach is to change your model to something like this:

class Vehicle(db.Model):
    ...
    start_production_date = db.DateProperty()
    start_production_year = db.IntegerProperty()
    start_production_month = db.IntegerProperty()
    start_production_day = db.IntegerProperty()

    end_production_date = db.DateProperty()
    end_production_year = db.IntegerProperty()
    end_production_month = db.IntegerProperty()
    end_production_day = db.IntegerProperty()

Update these new values on every put (you could override put) and the simply:

# specific year

q = (Vehicle.all()
    .filter('start_production_year =', 2010))

# specific year, different months

q = (Vehicle.all()
    .filter('start_production_year =', 2010)
    .filter('start_production_month IN', [1, 2, 3, 4]))

# different years

q = (Vehicle.all()
    .filter('start_production_year IN', [2010, 2011, 2012]))

Upvotes: 2

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