post {protocol}://{base-url}/integration/v2/bi/server//datasource/column/
POST /datasource/column/ creates and updates Datasource Column objects via external_id. If an object with a matching external_id exists, it is updated with the given payload. Otherwise, it is created. Note that this method is not allowed for non-virtual servers.
Datasource column objects will appear on the Fields tab on the datasource's catalog page in Alation.