Map Graph

Python simple Graph implementation for lightweight object mapping.

Usage

The graph leverages two dictionaries to keep track of the nodes and edges of the graph. Each node is expected to be referenced by a canonical id which is unique across the graph. Relationships are then established using these canonical ids.

Examples

You can create a graph and add nodes by doing the following:

from src.structures.mapping import Graph, MissingNodeError


graph = Graph('urn:oid:2.1.2.5565894.456')

loinc_id = 'http://www.loinc.org/10234-3'
loinc_code = {
    'code': '10234-3'
    'description': 'Sample Loinc Code'
}

person_id = 'urn:oid:2.1.3345.3234.2.1:33454'
person_node = {
    'name': 'jim smith',
    'age': 25,
}

graph.add_node(loinc_id, loinc_code)
graph.add_node(person_id, person_node)
graph.add_relationship(loinc_id, person_id)

Nodes are references by the canonical id. Retrieving these items can be accomplished through the get_node method:

person_id = 'urn:oid:2.1.3345.3234.2.1:33454'

person_node = graph.get_node(person_id)

Nodes that do not exist in the graph will return a MissingNodeError when there is an attempt to create a relationship with or retrieve a node by canonical id that does not exist.

from src.structures.mapping import Graph, MissingNodeError
import logging

graph = Graph('urn:oid:2.1.2.5565894.456')

loinc_id = 'http://www.loinc.org/10234-3'
loinc_code = {
    'code': '10234-3'
    'description': 'Sample Loinc Code'
}

person_id = 'urn:oid:2.1.3345.3234.2.1:33454'
person_node = {
    'name': 'jim smith',
    'age': 25,
}

graph.add_node(person_id, person_node)

try:
    graph.add_relationship([loinc_id, person_id])

except MissingNodeError as err:
    logging.error(err.message)