Código fuente para django.contrib.postgres.aggregates.statistics
from django.db.models import FloatField, IntegerField
from django.db.models.aggregates import Aggregate
__all__ = [
'CovarPop', 'Corr', 'RegrAvgX', 'RegrAvgY', 'RegrCount', 'RegrIntercept',
'RegrR2', 'RegrSlope', 'RegrSXX', 'RegrSXY', 'RegrSYY', 'StatAggregate',
]
class StatAggregate(Aggregate):
output_field = FloatField()
def __init__(self, y, x, output_field=None, filter=None):
if not x or not y:
raise ValueError('Both y and x must be provided.')
super().__init__(y, x, output_field=output_field, filter=filter)
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
return super().resolve_expression(query, allow_joins, reuse, summarize)
[documentos]class CovarPop(StatAggregate):
def __init__(self, y, x, sample=False, filter=None):
self.function = 'COVAR_SAMP' if sample else 'COVAR_POP'
super().__init__(y, x, filter=filter)
[documentos]class RegrCount(StatAggregate):
function = 'REGR_COUNT'
output_field = IntegerField()
def convert_value(self, value, expression, connection):
return 0 if value is None else value