bento_meta.entity

This module contains * Entity, the base class for metamodel objects, * the CollValue class to manage collection-valued attributes, and * the ArgError exception.

Exceptions

ArgError

Exception for method argument errors.

Classes

Entity	Base class for all metamodel objects.
CollValue	A UserDict for housing Entity collection attributes.

Module Contents

exception bento_meta.entity.ArgError

Bases: Exception

Exception for method argument errors.

class bento_meta.entity.Entity(init: dict | neo4j.graph.Node | Entity | None = None)

Base class for all metamodel objects.

Entity contains all the magic for metamodel objects such as bento_meta.objects.Node and ‘bento_meta.object.Edge`. It will rarely be used directly. Entity redefines __setattr__ and __getattr__ to enable graph database object mapping under the hood.

The Entity class also defines private and declared attributes that are common to all metamodel objects. It provides the machinery to manage private attributes separately from declared attributes, and to raise exceptions when attempts are made to access attributes that are not declared.

pvt_attr = ['pvt', 'neoid', 'dirty', 'removed_entities', 'attspec', 'mapspec', 'belongs']

defaults

attspec_

attspec

mapspec_

property object_map

pvt

neoid = None

property dirty

Flag whether this instance has been changed since retrieval from the database.

Set to -1, ensure that the next time an attribute is accessed, the instance will retrieve itself from the database.

property removed_entities

property belongs

Dict that stores information on the owners (referents) of this instance in the model

classmethod mapspec() → dict[str, str | dict[str, str]]

The object to database mapping specification.

Is a class method, not a property.

classmethod default(propname)

Returns a default value for the property named, or None if no default defined.

get_by_id(id: str)

Get an object from the db with the id attribute (not the Neo4j id).

Returns a new object. :param string id: value of id for desired object

clear_removed_entities()

set_with_dict(init: dict) → None

set_with_node(init)

set_with_entity(ent)

__getattribute__(name: str) → Any

__getattr__(name: str) → Any

__setattr__(name: str, value: Any) → None

_set_declared_attr(name, value)

__delattr__(name: str) → None

_check_init(init) → None

_check_value(att, value)

dup()

Duplicate the object, but not too deeply.

delete() → None

Delete self from the database.

dget(*, refresh: bool = False)

Update self from the database.

Parameters:

refresh (boolean) – if True, force a retrieval from db;

if False, retrieve from cache; don’t disrupt changes already made

dput()

Put self to the database.

This will set the neoid property if not yet set.

rm(force)

Delete self from the database. The object instance survives.

classmethod attr_doc()

Create a docstring for declared attributes on class as configured.

get_label() → str

Return type of entity as label.

get_attr_dict() → dict[str, str]

Return simple attributes set for Entity as a dict.

Attr values are converted to strings. Doesn’t include attrs with None values.

class bento_meta.entity.CollValue(init=None, *, owner: Entity, owner_key: str)

Bases: collections.UserDict

A UserDict for housing Entity collection attributes.

This class contains a hook for recording the Entity that owns the value that is being set. The value is marked as belonging to the containing object, not this collection object. It also protects against adding arbitrarily typed elements to the collection; it throws unless a value to set is an Entity. __setitem__.

Parameters:

• owner – Entity object of which this collection is an attribute

• owner_key – the attribute name of this collection on the owner

property owner: Entity

The entity instance of which this collection is an attribute.

property owner_key: str

The attribute name of this collection on the owner.

__setitem__(name, value)

__getitem__(name: str) → Any

__delitem__(name: str) → None