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========
Usage
========
To use oslo.db in a project::
* Session Handling
.. code:: python
from oslo.config import cfg
from oslo.db.sqlalchemy import session as db_session
_FACADE = None
def _create_facade_lazily():
global _FACADE
if _FACADE is None:
_FACADE = db_session.EngineFacade.from_config(cfg.CONF)
return _FACADE
def get_engine():
facade = _create_facade_lazily()
return facade.get_engine()
def get_session(**kwargs):
facade = _create_facade_lazily()
return facade.get_session(**kwargs)
* Base class for models usage
.. code:: python
from oslo.db import models
class ProjectSomething(models.TimestampMixin,
models.ModelBase):
id = Column(Integer, primary_key=True)
...
* DB API backend support
.. code:: python
from oslo.config import cfg
from oslo.db import api as db_api
_BACKEND_MAPPING = {'sqlalchemy': 'project.db.sqlalchemy.api'}
IMPL = db_api.DBAPI.from_config(cfg.CONF, backend_mapping=_BACKEND_MAPPING)
def get_engine():
return IMPL.get_engine()
def get_session():
return IMPL.get_session()
# DB-API method
def do_something(somethind_id):
return IMPL.do_something(somethind_id)
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