Knowledge graph

Points assumed for current implementation:

• List of content already in place.
• Content is for a Syllabus
• Syllabus is for a subject and a standard

A content tree should be created where the concepts are linked to eachother which would help in suggesting the user with pre-requisites.

Two approaches: Nested Set or Adjacency list.

Adjacency list, although much easier to maintain, in RDBMS, will slow down the process, so I will be approaching with Nested Sets.

Tools

• Django-Tastypie
• Django-mptt

API Spec.

• Creation: user should be able to send complex tree structure for a syllabus and tree should be stored. (Implemented)
• Update: user should be able to send (patch) updates, which command the node to be moved anywhere in the current tree. (Implemented)
• Update: user should be able to add new nodes in existing tree.
• Read: user should be able to retrieve tree for a syllabus. (Implemented)
• Delete: user should be able to delete any node.
• Read Detail: When accessing a node, api should tell us about the siblings to the left (prerequistes)

UI

• Ideal UI would be a list of all content (searchable) on the left side, from where each item can be drawn and placed on the right side for creation of tree.

Implemented API:

VERB	URL	Details
POST	/content_tree	send a Post request to content_tree with initial structure of your tree
PATCH	/content_tree/move_node	send a PATCH request with data: postion, node_id, target_id
GET	/content_tree?content__syllabus__standard=2&content__syllabus__subject=1	Get the content tree for a syllabus
GET	/content_tree/:node_id	Get Tree structure with given node at root
DELETE	Not implemented yet
GET	/content/?syllabus__standard=1&syllabus__subject=2	Get all the content for this syllabus(standard + subject)

To do:

-   API to add nodes once the tree is created.
-   API to get siblings to left of current node.
-   API to get siblings to right of current node.
-   API to get parent of current node.
-   API to get only children of current node.
-   UI: where initial creation is done by dragging the items from a different tree 

Instructions:

• Setup a database and change settings
• pip install -r requirements.txt
• python manage.py runserver (run on 8000)
• create a super user and login to django admin and create some sample standard, subject, syllabus and content.