`cliche.orm` — Object-relational mapping¶

Cliche uses the relational database and data on the database are mapped to objects. It widely uses SQLAlchemy as its ORM (object-relational mapping) framework.

In order to define a persist model class, just subclass Base:

from sqlalchemy import Column, Integer, UnicodeText

from .orm import Base


class Thing(Base):
    '''A something object-relationally mapped.'''

    id = Column(Integer, primary_key=True)
    value = Column(UnicodeText, nullable=False)
    __repr_columns = id, value
    __tablename__ = 'things'

class cliche.orm.Base(**kwargs)¶

SQLAlchemy declarative base class.

__repr_columns__¶: (collections.abc.Sequence) This columns will be printed to repr() string of its instances if __repr_columns__ is defined.

See also

SQLAlchemy — Using the Session: Session is the primary usage interface for persistence operations.

cliche.orm.downgrade_database(engine, revision)¶

Reverts to a previous revision.

Parameters:	engine (`sqlalchemy.engine.base.Engine`) – the database engine to revert revision (`str`) – the previous revision to revert to

cliche.orm.get_alembic_config(engine)¶

Creates a configuration for alembic. You can pass an Engine object or a string of database url either. So:

from sqlalchemy import create_engine
engine = create_engine('postgresql://localhost/cliche')
alembic_cfg = get_alembic_config(engine)

is equivalent to:

db_url = 'postgresql://localhost/cliche'
alembic_cfg = get_alembic_config(db_url)

Parameters:	engine (`sqlalchemy.engine.base.Engine`, `str`) – the database engine to use
Returns:	an alembic config
Return type:	`alembic.config.Config`

cliche.orm.get_database_revision(engine)¶

Gets the current revision of the database.

Parameters:	engine (`sqlalchemy.engine.base.Engine`) – the database engine to get the current revision
Returns:	the script of the current revision
Return type:	`alembic.script.Script`

cliche.orm.import_all_modules(dry_run=False)¶

Import all submodules of cliche to ensure every ORM entity classes are ready to use. It’s useful for being ready to auto-generate a migration script.

Returns:	the set of module names
Return type:	`collections.abc.Set`

cliche.orm.initialize_database(engine)¶

Creates all database schemas and stamps it as the head of versions.

Parameters:	engine (`sqlalchemy.engine.base.Engine`) – the database engine to initialize

cliche.orm.upgrade_database(engine, revision='head')¶

Upgrades the database schema to the chosen revision (default is head).

Parameters:	engine (`sqlalchemy.engine.base.Engine`) – the database engine to upgrade revision (`str`) – the revision to upgrade to. default is `'head'`

cliche.orm — Object-relational mapping¶

`cliche.orm` — Object-relational mapping¶