zeekay
dda3979851
This is our fork, so it should read like it. `import datastore_orm` instead of `from infi.clickhouse_orm import ...`: `infi` was the original vendor's org namespace, and carrying someone else's org name through every import in the consuming codebase is not a fork, it is a vendored copy that never got renamed. The `infi` namespace package is gone entirely (src/infi/__init__.py with it), the distribution is `datastore-orm`, and the metadata points at Hanzo rather than at the upstream repo and author. NOT renamed, deliberately: the migration history tables are still `infi_clickhouse_orm_migrations`. That name is persisted state — 448 rows in production key off it — so changing it is a data migration, not a rename. Doing it carelessly reproduces the exact failure this fork just hit, where a package rename orphaned the history and silently blocked every migration.
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What's New in Version 2
Python 3.5+ Only
This version of the ORM no longer support Python 2.
New flexible syntax for database expressions and functions
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.
Support for IPv4 and IPv6 fields
Two new fields classes were added: IPv4Field and IPv6Field. Their values are represented by Python's ipaddress.IPv4Address and ipaddress.IPv6Address.
See Field Types.
Automatic generation of models by inspecting existing tables
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)
Convenient ways to import ORM classes
You can now import all ORM classes directly from datastore_orm, without worrying about sub-modules. For example:
from datastore_orm import Database, Model, StringField, DateTimeField, MergeTree