The content’s structure is symbolized by knowledge edges. Knowledge edges are the last objects to instantiate while setting up your content on our API. It gives you a simple way to build your learning path.\\

{{ :api1:knowledge_structure:knolwedge_edge_v1.png?600 | Knowledge Edge example}}


===Object resources===
^ Property     ^ Type      ^ Description         ^
| knowledge_graph_id | Integer | The knowledge graph the knowledge edge belongs to |
| source_node_id | Integer | The source node of the knowledge edge |
| destination_node_id | Integer | The destination node of the knowledge edge |
| instance_id | Integer | The instance the knowledge edge belongs to |
| direct | Boolean | A direct prerequisite link. If false, abstract link between source and destination nodes |
| hops | Integer | Number of links between source and destination nodes |
| distance | Integer | Number of nodes between source and destination nodes |
| created_at | Timestamp | The creation date of the object |
| updated_at | Timestamp | The last update date of the object |


===Create (POST)===

^ Method | POST |
^ URL | /knowledge_edges |

==Parameters (*Requiered parameters)==

^ Property     ^ Type      ^ Description         ^
| knowledge_graph_id* | Integer | The knowledge graph the knowledge edge belongs to |
| source_node_id* | Integer | The source node of the knowledge edge |
| destination_node_id* | Integer | The destination node of the knowledge edge |

==Send the request (JSON input example)==

<code>
{
	knowledge_graph_id: 1,
	source_node_id: 1,
	destination_node_id: 2
}
</code>

==Get the response (JSON output example)==

<code>
{
	id: 1,
	knowledge_graph_id: 1,
	source_node_id: 1,
	destination_node_id: 2,
	instance_id : 1,
	created_at : 2014-09-17 09:21:03,
	updated_at : 2014-09-17 09:21:03
}
</code>

===Fetch (GET)===

^ Method | GET|
^ URL | /knowledge_edges/{knowledge_edge_id} |

If no knowledge_edge_id is provided it will fetch all the Knowledge Edges for your instance.

==Get the response (JSON output example)==

**With ID provided**\\

<code>
{
	id: 1,
	knowledge_graph_id: 1,
	source_node_id: 1,
	destination_node_id: 2,
	instance_id : 1,
	direct: true,
	hops: 1,
	distance: 1,
	created_at : 2014-09-17 09:21:03,
	updated_at : 2014-09-17 09:21:03
}
</code>


**Without ID provided**\\
<code>
[
	{
		id: 1,
		knowledge_graph_id: 1,
		source_node_id: 1,
		destination_node_id: 2
	},
	{
		id: 2,
		knowledge_graph_id: 1,
		source_node_id: 1,
		destination_node_id: 3
	}
]
</code>

===Fetch Knowledge Edges by Knowledge Node (GET)===

You can get all related Knowledge Edges for a given Source Knowledge Node\\

^ Method | GET |
^ URL | /knowledge_nodes/{knowledge_node_id}/knowledge_edges |