bento_meta.object_map

This module contains ObjectMap, a class which provides the machinery for mapping bento_meta objects to a Bento Metamodel Database in Neo4j. Mostly not for human consumption. The ObjectMap:

interprets the attribute specification (attspec) and map specification (mapspec) associated with Entity subclasses
provides the get() and put() methods to subclasses, that enable them to get and put themselves to the database
generates appropriate

Cypher <https://neo4j.com/docs/cypher-manual/current/> queries to do gets and puts One ObjectMap instance should be generated for each Entity subclass (see, e.g., bento_meta.model.Model)

Classes

ObjectMap

Machinery for mapping bento_meta objects to a Bento Metamodel Database in Neo4j.

Module Contents

class bento_meta.object_map.ObjectMap(*, cls: type[bento_meta.entity.Entity] | None = None, drv: neo4j.Driver | None = None)[source]

Machinery for mapping bento_meta objects to a Bento Metamodel Database in Neo4j.

Mostly not for human consumption.

cache: ClassVar[dict]

cls = None

maps

classmethod clear_cache() → None[source]: Clear the cache.

classmethod cls_by_label(lbl: str) → type[bento_meta.entity.Entity] | None[source]: Get the class by label.

classmethod keys_by_cls_and_reln(qcls: type[bento_meta.entity.Entity], reln: str) → tuple[str, str | None] | None[source]: Get the keys by class and relationship.

classmethod _quote_val(value: str | float | None, *, single: bool | None = None) → str | float | None[source]: Quote the value unless single is set.

get_by_id(obj: bento_meta.entity.Entity, id: str, *, refresh: bool = False) → bento_meta.entity.Entity | None[source]: Get an entity given an id attribute value (not the Neo4j id).

get_by_node_nanoid(obj: bento_meta.entity.Entity, nanoid: str, *, refresh: bool = False) → bento_meta.entity.Entity | None[source]: PROTOTYPE: Get an entity given an id attribute value (not the Neo4j id).

get(obj: bento_meta.entity.Entity, *, refresh: bool = False) → bento_meta.entity.Entity[source]: Get the data for an object instance from the db and load the instance with it.

put(obj: bento_meta.entity.Entity) → bento_meta.entity.Entity[source]: Put the object instance’s attributes to the mapped data node in the database.

rm(obj: bento_meta.entity.Entity, *, force: bool | int = False) → Any | None[source]: ‘Delete’ the object’s mapped node from the database.

add(obj: bento_meta.entity.Entity, att: str, tgt: bento_meta.entity.Entity) → Any[source]

Create a link between an object instance and a target object in the database.

This represents adding an object-valued attribute to the object.

Parameters:

obj – The object instance to add attribute to.
att – The attribute name.
tgt – The target entity to link.

Returns:

The Neo4j ID of the target, or None if not found.

drop(obj: bento_meta.entity.Entity, att: str, tgt: bento_meta.entity.Entity, tx: neo4j.Transaction | None = None) → Any[source]

Remove an existing link between an object instance and a target object in the database.

This represents dropping an object-valued attribute from the object.

Parameters:

obj – The object instance to remove attribute from.
att – The attribute name.
tgt – The target entity to unlink.
tx – Optional transaction to use for the operation.

Returns:

The result value, or None if not found.

get_owners(obj: bento_meta.entity.Entity) → list[tuple[bento_meta.entity.Entity, tuple[str, str | None] | None]][source]: Get the nodes which are linked to the object instance (the owners of the object).

get_q(obj: bento_meta.entity.Entity) → str[source]: Get the query for an object.

get_by_id_q() → str[source]: Get the query for an entity by its Neo4j id.

get_by_node_nanoid_q() → str[source]: PROTOTYPE: Get the query for an entity given its nanoid.

get_attr_q(obj: bento_meta.entity.Entity, att: str) → str[source]: Get the query for an attribute of an object.

get_owners_q(obj: bento_meta.entity.Entity) → str[source]: Get the query for the owners of an object.

put_q(obj: bento_meta.entity.Entity) → list[str][source]: Get the query for putting an object.

put_attr_q(obj: bento_meta.entity.Entity, att: str, values: bento_meta.entity.Entity | list[bento_meta.entity.Entity] | bento_meta.entity.CollValue) → str | list[str][source]: Get the query for putting an attribute of an object.

rm_q(obj: bento_meta.entity.Entity, *, detach: bool = False) → str[source]: Get the query for removing an object.

rm_attr_q(obj: bento_meta.entity.Entity, att: str, values: list[bento_meta.entity.Entity] | None = None) → str | list[str][source]: Get the query for removing an attribute of an object.

_check_values_list(att: str, values: list[bento_meta.entity.Entity] | bento_meta.entity.CollValue) → bool[source]: Check if the values are a list of mapped Entity objects of the appropriate subclass for an attribute.