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Itai Shirav 2016-06-26 15:11:23 +03:00
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Overview
========
This is an Infinidat project.
Usage
-----
Nothing to use here.
Checking out the code
=====================
Run the following commands:
easy_install -U infi.projector
projector devenv build

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Overview
========
This project is simple ORM for working with the `ClickHouse database <https://clickhouse.yandex/>`_.
It allows you to define model classes whose instances can be written to the database and read from it.
Installation
============
To install infi.clickhouse_orm::
pip install infi.clickhouse_orm
Usage
=====
Defining Models
---------------
Models are defined in a way reminiscent of Django's ORM:
.. code:: python
from infi.clickhouse_orm import models, fields, engines
class Person(models.Model):
first_name = fields.StringField()
last_name = fields.StringField()
birthday = fields.DateField()
height = fields.Float32Field()
engine = engines.MergeTree('birthday', ('first_name', 'last_name', 'birthday'))
It is possible to provide a default value for a field, instead of it's "natural" default (empty string for string fields, zero for numeric fields etc.).
See below for the supported model field types.
Using Models
------------
Once you have a model, you can create model instances:
.. code:: python
>>> dan = Person(first_name='Dan', last_name='Schwartz')
>>> suzy = Person(first_name='Suzy', last_name='Jones')
>>> dan.first_name
u'Dan'
When values are assigned to a model fields, they are immediately converted to their Pythonic data type.
In case the value is invalid, a ValueError is raised:
.. code:: python
>>> suzy.birthday = '1980-01-17'
>>> suzy.birthday
datetime.date(1980, 1, 17)
>>> suzy.birthday = 0.5
ValueError: Invalid value for DateField - 0.5
>>> suzy.birthday = '1922-05-31'
ValueError: DateField out of range - 1922-05-31 is not between 1970-01-01 and 2038-01-19
To write your instances to ClickHouse, you need a Database instance:
.. code:: python
from infi.clickhouse_orm.database import Database
db = Database('my_test_db')
This automatically connects to http://localhost:8123 and creates a database called my_test_db, unless it already exists.
If necessary, you can specify a different database URL and optional credentials:
.. code:: python
db = Database('my_test_db', db_url='http://192.168.1.1:8050', username='scott', password='tiger')
Using the Database instance you can create a table for your model, and insert instances to it:
.. code:: python
db.create_table(Person)
db.insert([dan, suzy])
The insert method can take any iterable of model instances, but they all must belong to the same model class.
Field Types
-----------
Currently the following field types are supported:
- UInt8Field
- UInt16Field
- UInt32Field
- UInt64Field
- Int8Field
- Int16Field
- Int32Field
- Int64Field
- Float32Field
- Float64Field
- StringField
- DateField
- DateTimeField
Development
===========
After cloning the project, run the following commands::
easy_install -U infi.projector
cd infi.clickhouse_orm
projector devenv build
To run the tests, ensure that the ClickHouse server is running on http://localhost:8123/ (this is the default), and run::
bin/nosetests