edgeable 0.0.13

Easy to use, in memory, peristable graph database.

Edgeable

Edgeable was designed as an easy to use, in memory, peristable graph database. It is perfect for prototyping, exploring, and quick implementation in Python applications. Nodes have one string identifier and an unlimited number of key:value properties. They are connected by directed or non-directed (default) edges. These edges can also have an unlimited number of key:value properties. Additional convenience capabilities, like route detection through the graph are built-in.

Installation

The Edgeable database library can easily be installed with pip using pip install edgeable.

Example

from edgeable import GraphDatabase

db = new GraphDatabase()
A = db.put_node('A', {'type': 'building'})
B = db.put_node('B', {'type': 'classroom'})
A.attach(B, {'relationship': 'contains'})

Classes

Database Class

The GraphDatabase class represents the entire graph. Instances of GraphDatabase provide the ability to retrieve and creates nodes, as well as save or load from the file system.

Constructor

The GraphDatabase(filename="graph.db") constructor is used to create a graph database instance. It optionally takes a filename to use when saving or loading the database to the file system.

Persistance

• load() - Load the database from the file system.
• save() - Save the database to the file system.

Nodes and Edges

• get_node_count() - Return the number of nodes in the database.
• get_edge_count() - Return the number of edges in the database.
• has_node(id) - Taking a node identifier, return an instance of type GraphNode.
• put_node(id, properties={}) - Creates or retrieves the instance of GraphNode with the provided identifier. The optionally provided properties are set or updated on the node.
• get_nodes(criteria=lambda node: True) - Retrieve a list of GraphNode instances from the database. If the optional criteria is not provided, all nodes are returned, otherwise the criteria function is used to return only matching nodes.

Node Class

The GraphNode class represent nodes and associated properties within the graph. Nodes can be connected through directed or non-directed edges.

• delete() - Delete the node from the database, removing any associated edges.

Edges

• attach(destination, properties={}, directed=False) - Attach the current node to the destination node with a new edge. The optionally provided properties will be set on the edge, whether it exists or is created new. The releationship will be nondirectional unless directed is set to True. The method returns a boolean indicating if a new edge was created between the nodes.
• detach(destination=None, directed=False) - Detach the current node from the destination node, removing any connecting edge. If no destination is provided, all attached nodes are detached. If directed is set to True, then the edge is only removed in the current direction, any edge in the other directions is untouched. The method returns a boolean indicating if any edges were removed.
• get_edges(criteria=lambda edge: True) - Retrieve a list of GraphEdge instances from the database. If the optional criteria is not provided, all edges for the node are returned, otherwise the criteria function is used to return only matching edges.
• get_edge(destination) - Retrieve the edge that leads from the current node to the provided destination node.

Properties

• set_property(key, value) - Set a property on the node with the provided key and value.
• get_property(key) - Retrieve the node's property value for the provided key.
• get_properties() - Retrieve a dict containing all properties set on the node.

Routes

• find_routes_to(end, effort=5)
• find_route_to(end, skip=[])

Edge Class

The GraphEdge class representes the connections between GraphNode instances in the database. All methods assume edges are nondirected, so interactions with edges equally manipulates an edge in each direction between nodes. This behavior can be overridden for specific calls, resulting in the creation, modification, or deletion of directional edges.

• get_destination() - Retrieve the GraphNode instance that is the destination of this edge.
• get_source() - Retrieve the GraphNode instance that is the source of this edge.
• delete(directed=False) - Delete the edge from the database. If directed is True than only the edge in this direction is deleted.

Properties

• set_property(key, value, directed=False) - Set a property on the node with the provided key and value. If directed is True than the property is set only on the edge in this direction.
• get_property(key) - Retrieve the node's property value for the provided key.
• get_properties() - Retrieve a dict containing all properties set on the edge.

Resources

Build process: https://app.travis-ci.com/github/LeeAdcock/edgeable PyPi: https://pypi.org/project/edgeable/