This version of the ORM no longer support Python 2.
Expressions that use model fields, database functions and Python operators are now first-class citizens of the ORM. They provide infinite expressivity and flexibility when defining models and generating queries.
Example of expressions in model definition:
class Temperature(Model):
station_id = UInt16Field()
timestamp = DateTimeField(default=F.now()) # function as default value
degrees_celsius = Float32Field()
degrees_fahrenheit = Float32Field(alias=degrees_celsius * 1.8 + 32) # expression as field alias
# expressions in engine definition
engine = MergeTree(partition_key=[F.toYYYYMM(timestamp)], order_by=[station_id, timestamp])Example of expressions in queries:
db = Database('default')
start = F.toStartOfMonth(F.now())
expr = (Temperature.timestamp > start) & (Temperature.station_id == 123) & (Temperature.degrees_celsius > 30)
for t in Temperature.objects_in(db).filter(expr):
print(t.timestamp, t.degrees_celsius)See Expressions.
Two new fields classes were added: IPv4Field and IPv6Field. Their values are represented by Python's ipaddress.IPv4Address and ipaddress.IPv6Address.
See Field Types.
It is now easy to generate a model class on the fly for an existing table in the database using Database.get_model_for_table. This is particularly useful for querying system tables, for example:
QueryLog = db.get_model_for_table('query_log', system_table=True)
for row in QueryLog.objects_in(db).filter(QueryLog.query_duration_ms > 10000):
print(row.query)You can now import all ORM classes directly from clickhouse_orm, without worrying about sub-modules. For example:
from clickhouse_orm import Database, Model, StringField, DateTimeField, MergeTree