#I have created all relationship example.
#1. Has One & Belongs To
Example 1: User has_one :pancard PanCard belongs_to :user
rails g controller User
rails g model User User name:string country:string
rails g model PanCard pan_number:bigint user:references
Example 2: User has_one :biography Biography belongs_to :user
User Controller + Model already have created
rails g model Biography bio:text user:references
#2. Has Many
Example 1: Car has_many :parts Part belongs_to :user
Example 2: Mobile has_many :apps App belongs_to :mobile
#3. HABTM
Example 1: Example 2:
#4. Polymorphic How to create impliment a polymorphic relationship.
Example 1: User has_many :address address belongs_to :user
Example 2: Post has_many :comments Article has_many :comments
comments: belongs_to :post
#5. Has One Through
Example 1: Example 2:
#6. Has Many Through
Example 1: Example 2: