pydantic-neo4j 0.3.0

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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,
                            SequenceCriteriaNodeModel,
                            SequenceCriteriaRelationshipModel,  
                            SequenceQueryModel, 
                            SequenceNodeModel)

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• 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

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• 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

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• 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)

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

nodes = await match_util.node_query(node_name='Manufacturer')
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• Query the graph for multiple nodes. Lets find all nodes that are active

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

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• Query the graph for a single relationship. Lets find a manufacturer that produces a red design
• This will be depreciated soon, use sequence query instead

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)

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• 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(SequenceCriteriaNodeModel(name='Manufacturer'))
sequence_query.relationship_sequence.append(SequenceCriteriaRelationshipModel()) # a relationship with no criteria
sequence_query.node_sequence.append(SequenceCriteriaNodeModel() # a node with no criteria specified
sequence_query.relationship_sequence.append(SequenceCriteriaRelationshipModel()) #a realtoinship with no criteria
sequence_query.node_sequence.append(SequenceCriteriaNodeModel(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)

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• Run a specific query, lets delete everything

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

Not Implemented

• Update a node

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• Update a sequence

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• Delete a node

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