https://github.com/stellasia/nodes2022

Code shown at the NODES 2022 conference - Python/Neo4j OGM
https://github.com/stellasia/nodes2022

cypher neo4j nodes-2022 ogm python

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Code shown at the NODES 2022 conference - Python/Neo4j OGM

• Host: GitHub
• URL: https://github.com/stellasia/nodes2022
• Owner: stellasia
• License: mit
• Created: 2022-11-14T15:03:46.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2022-11-25T10:45:24.000Z (about 2 years ago)
• Last Synced: 2023-03-01T14:05:32.572Z (almost 2 years ago)
• Topics: cypher, neo4j, nodes-2022, ogm, python
• Language: Python
• Homepage:
• Size: 12.7 KB
• Stars: 4
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# NODES 2022

Accompanying code for my talk at the 

[NODES 2022](https://hopin.com/events/nodes-2022/registration) 

conference titled: "Building a Python/Neo4j OGM".

## Video

[![image](https://img.youtube.com/vi/DKziks5jQvc/maxresdefault.jpg)](https://youtu.be/DKziks5jQvc)

## Usage

Each folder can be seen as a new "branch", where features are

added incrementally.

    pip install -r requirements.txt

    export PYTHONPATH=.$PYTHONPATH

    pytest /tests.py

```bash

 pytest 00-movie-creation/tests.py

 pytest 01-node-class/tests.py 

 pytest 02-property-attributes/tests.py

 pytest 03-manager-match/tests.py 

 pytest 04-relationship-property-fetch-and-cache/tests.py 

 pytest 05-prefetch/tests.py 

```

## Content

- **00-movie-creation**: movie class and hard-coded CREATE statement

- **01-node-class**: Property and Node (w/ metaclass) => all subclasses of the `Node` class now have 

    a `_properties` attribute with a list of properties they accept

- **02-property-attributes**: define a Property as required (NB: skipped during the talk)

- **03-manager-match**: dynamically build MATCH clause, RETURN statement, object hydration from DB

- **04-relationship-property-fetch-and-cache**: define RelationshipProperty and ability to fetch the data

    when the field is accessed (ie when using `movie.actors` for instance)

- **05-prefetch**: ability to prefetch related object during the MATCH query thanks to Cypher map projection

## Map projection examples

```

MATCH (node:Movie {title: "Cloud Atlas"}) 

RETURN node { .* }

MATCH (node:Movie {title: "Cloud Atlas"}) 

RETURN node { .title, _id: id(node) }

MATCH (node:Movie {title: "Cloud Atlas"})

RETURN node {

     .title, 

     actors: [(node)<-[:ACTED_IN]-(person:Person) 

                 | person { .name }

            ]

}

MATCH (node:Movie {title: "Cloud Atlas"})

RETURN node {

     .title, 

     actors: [

        (node)<-[:ACTED_IN]-(person:Person) 

         | person { 

            .name, 

            directed: [

                (person)-[:DIRECTED]->(directed:Movie)

                | directed { .* }

            ] 

         }

     ]

}

```

## Full code

The code presented here is a simplified version extracted

from this project: [pentaquark](https://github.com/stellasia/pentaquark)