GET /PUT scenario in single entity

Hi All,

We are trying one POC with NW Gateway service to test with get and set method.

We could achieve get_entity and get_entity_set to retrieve all material no to a given entity.

Now to the same entity we need to update which is not happening . Please guide us how to do update the material attributes which are searched from get_entity set above.

We tried implementing  get_entity and get_entityset for search material 

To update we tried implementing update_entity and tested with PUT method but it did not work.

Please suggest to update which method to be implemented and how we need to test the same.

Also please suggest how to create test data for http request.

Regards

Vijay