Odoo models.py BaseModel

class BaseModel(object):
    """ Base class for OpenERP models.

    OpenERP models are created by inheriting from this class' subclasses:

    *   :class:`Model` for regular database-persisted models 常用数据库模型

    *   :class:`TransientModel` for temporary data, stored in the database but
        automatically vacuumed every so often 临时模型

    *   :class:`AbstractModel` for abstract super classes meant to be shared by
        multiple inheriting model 抽象模型 不保存

    The system automatically instantiates every model once per database. Those
    instances represent the available models on each database, and depend on
    which modules are installed on that database. The actual class of each
    instance is built from the Python classes that create and inherit from the
    corresponding model.

    Every model instance is a "recordset", i.e., an ordered collection of
    records of the model. Recordsets are returned by methods like
    :meth:`~.browse`, :meth:`~.search`, or field accesses. Records have no
    explicit representation: a record is represented as a recordset of one
    record.

    To create a class that should not be instantiated, the _register class
    attribute may be set to False.
    """
    __metaclass__ = MetaModel
    _auto = True # create database backend
    _register = False # Set to false if the model shouldn't be automatically discovered.
    _name = None
    _columns = {}
    _constraints = []
    _custom = False
    _defaults = {}
    _rec_name = None
    _parent_name = 'parent_id'
    _parent_store = False
    _parent_order = False
    _date_name = 'date'
    _order = 'id'
    _sequence = None
    _description = None
    _needaction = False
    _translate = True # set to False to disable translations export for this model

    # dict of {field:method}, with method returning the (name_get of records, {id: fold})
    # to include in the _read_group, if grouped on this field
    _group_by_full = {}

    # Transience
    _transient = False # True in a TransientModel

    # structure:
    #  { 'parent_model': 'm2o_field', ... }
    _inherits = {}

    # Mapping from inherits'd field name to triple (m, r, f, n) where m is the
    # model from which it is inherits'd, r is the (local) field towards m, f
    # is the _column object itself, and n is the original (i.e. top-most)
    # parent model.
    # Example:
    #  { 'field_name': ('parent_model', 'm2o_field_to_reach_parent',
    #                   field_column_obj, origina_parent_model), ... }
    _inherit_fields = {}

    _table = None
    _log_create = False
    _sql_constraints = []

    # model dependencies, for models backed up by sql views:
    # {model_name: field_names, ...}
    _depends = {}

    CONCURRENCY_CHECK_FIELD = '__last_update'