pandora/pandora/oxdjango/query.py

58 lines
1.8 KiB
Python

# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4
from django.db.models.sql import Query
from django.db.models.sql.compiler import SQLCompiler
from django.db import connections
import django.db.models.query
'''
models.py:
-----------------------------------
from oxdjango.query import QuerySet
class Manager(models.Manager):
def get_query_set(self):
return QuerySet(self.model)
class Model(models.Model):
...
objects = Manager()
'''
class NullLastSQLCompiler(SQLCompiler):
def get_order_by(self):
result = super(NullLastSQLCompiler, self).get_order_by()
if self.query.nulls_last and result \
and self.connection.vendor == 'postgresql':
return [(expr, (sql + ' NULLS LAST', params, is_ref))
for (expr, (sql, params, is_ref)) in result]
return result
class NullsLastQuery(Query):
nulls_last = False
def clone(self, *args, **kwargs):
obj = super(NullsLastQuery, self).clone(*args, **kwargs)
obj.nulls_last = self.nulls_last
return obj
def get_compiler(self, using=None, connection=None):
if using is None and connection is None:
raise ValueError("Need either using or connection")
if using:
connection = connections[using]
return NullLastSQLCompiler(self, connection, using)
class QuerySet(django.db.models.query.QuerySet):
def __init__(self, model=None, query=None, using=None, **kwargs):
super(QuerySet, self).__init__(model=model, query=query, using=None, **kwargs)
self.query = query or NullsLastQuery(self.model)
def order_by(self, *args, **kwargs):
nulls_last = kwargs.pop('nulls_last', False)
obj = super(QuerySet, self).order_by(*args, **kwargs)
obj.query.nulls_last = nulls_last
return obj