def add_bucket_field_to_query(self, q, q_entities, field, field_entity):
# Get min, max if not provided.
field_min = 0
field_max = 0
if not field.has_key("min") or not field.has_key("max"):
field_min, field_max = self.get_field_min_max(field)
# Override calculated min/max if values were provided.
if field.has_key("min"):
field_min = field.get("min")
if field.has_key("max"):
field_max = field.get("max")
num_buckets = field.get("num_buckets", 10)
# Get bucket width.
bucket_width = (field_max - field_min) / num_buckets
# Get bucket field entities.
# Bit of a trick here: we use field_max - bucket_width because normally last bucket gets all values >= field_max.
# Here we use one less bucket, and then filter. This essentially makes the last bucket include values <= field_max.
bucket_entity = func.width_bucket(field_entity, field_min, field_max - bucket_width, num_buckets - 1)
q = q.filter(field_entity <= field_max)
bucket_label_entity = (
cast(field_min + (bucket_entity - 1) * bucket_width, String)
+ " to "
+ cast(field_min + bucket_entity * bucket_width, String)
)
bucket_label_entity = bucket_label_entity.label(field["label"])
q_entities.add(bucket_label_entity)
return q, bucket_label_entity
def add_bucket_grouping_to_query(self, q, q_entities, entity, mapped_entity):
# Get min, max if not provided.
entity_min = 0
entity_max = 0
if (not entity.has_key('min') or not entity.has_key('max')):
entity_min, entity_max = self.get_entity_min_max(entity)
# Override calculated min/max if values were provided.
if entity.has_key('min'): entity_min = entity.get('min')
if entity.has_key('max'): entity_max = entity.get('max')
num_buckets = entity.get('num_buckets', 10)
entity_range = entity_max - entity_min
bucket_width = (entity_max - entity_min)/float(num_buckets)
# Get bucket field entities.
# Can use the line below in case db doesn't have width_bucket function.
#bucket_id_entity = func.greatest(func.round( (((mapped_entity - entity_min)/entity_range) * num_buckets ) - .5) + 1, num_buckets).label(self.get_bucket_id_label(entity))
bucket_id_entity = func.width_bucket(mapped_entity, entity_min, entity_max, num_buckets).label(self.get_bucket_id_label(entity))
q_entities.add(bucket_id_entity)
bucket_label_entity = case(
[(bucket_id_entity == num_buckets + 1, '[' + cast( entity_max, String) + ', ...)')],
else_ = '[' + cast(entity_min + bucket_width * (bucket_id_entity - 1), String ) + ', ' + cast(entity_min + bucket_width * (bucket_id_entity), String) + ')' ).label(entity['label'])
q_entities.add(bucket_id_entity)
q_entities.add(bucket_label_entity)
q = q.group_by(column(bucket_id_entity._label), column(bucket_label_entity._label))
return q
