pydantic-neo4j 0.2.0

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Purpose of the Package

• To translate from Pydantic models to Neo4j Graphs

Getting Started

• Install the package

pip install pydantic-neo4j

Usage

• Import the package and models

from pydantic_neo4j import (PydanticNeo4j, 
                            RelationshipQueryModel,
                            NodeModel,
                            SequenceCriteriaModel, 
                            SequenceQueryModel, 
                            SequenceNodeModel)

• Initialize the class and get the utilities

pydantic_neo4j = PydanticNeo4j(username='neo4j', password='neo4j', uri='neo4j://localhost:7687)
match_util = pydantic_neo4j.match_utilities
create_util = pydantic_neo4j.create_utilities
database_operations = pydantic_neo4j.database_operations

• Create some Pydantic models

class Manufacturer(NodeModel):
    name: str

class Design(NodeModel):
    color: str
    
class Component(NodeModel):
    name: str
    
class IsOrderable(RelationshipModel):
    pass

class Produces(RelationshipModel):
    design_revision: int

• Create the nodes and relationships. All relationships must have a start_node and end_node

relationships = []

manufacturer = Manufacturer(name="Acme")
design = Design(color="red")
produces = Produces(design_revision=3, start_node=manufacturer, end_node=design)

• Add to list

relationships.append(produces)

• Create another relationship and add it to the list

component = Component(component_type="widget")
is_orderable = IsOrderable(start_node=design, end_node=component)

relationships.append(is_orderable)

• Add the nodes and relationships to the graph

await create_util.create_relationships(relationships=relationships)

• Query the graph for a single node. Lets find a manufacturer

nodes = await match_util.node_query(node_name='Manufacturer')

• Query the graph for multiple nodes. Lets find all nodes that are active

nodes = await match_util.node_query(criteria={'active': True})

• Query the graph for a single relationship. Lets find a manufacturer that produces a red design

query = RelationshipQueryModel(
    start_node_name="Manufacturer",
    start_criteria={},
    end_node_name="Design",
    end_criteria={"color": "red"},
    relationship_name="Produces",
    relationship_criteria={})
result = await match_util.match_relationship(query=query)

• Query the graph for multiple relationships. Lets find all manufacturers that make a widget component
• This uses a sequence, which is a series of relationships. Similar to Neo4j Path

sequence_query = SequenceQueryModel()

sequence_query.node_sequence.append(SequenceCriteriaModel(name='Manufacturer'))
sequence_query.relationship_sequence.append(SequenceCriteriaModel()) # a relationship with no criteria specified
sequence_query.node_sequence.append(SequenceCriteriaModel() # a node with no criteria specified
sequence_query.relationship_sequence.append(SequenceCriteriaModel()) #a realtoinship with no criteria specified
sequence_query.node_sequence.append(SequenceCriteriaModel(component_type="widget", include_with_return=True)

• The sequence query must always have 1 more node than relationship.
• The order is important, and is a sequence. node - relationship - node - relationship - node

result = await match_util.sequence_query(sequence_query=sequence_query)

• Run a specific query, lets delete everything

await database_operations.run_query(query=f"match (n) detach delete n")

Not Implemented

• Update a node

nodes = await match_util.node_query(name='Manufacturer', criteria={name='Acme'})
for graph_id, node in nodes.items():
    node.name = "Acme2"
    await create_util.update_node(node=node)

• Update a relationship

    query = RelationshipQueryModel(
    start_node_name="Manufacturer",
    start_criteria={},
    end_node_name="Design",
    end_criteria={"color": "red"},
    relationship_name="Produces",
    relationship_criteria={})
    result = await match_util.match_relationship(query=query)
    for graph_id, relationship in result.items():
        relationship.design_revision = 4
        await create_util.update_relationship(relationship=relationship)

• Delete a node

nodes = await match_util.node_query(name='Manufacturer', criteria={name='Acme'})
for graph_id, node in nodes.items():
    await create_util.delete_node(node=node)