schema

Postgres Database Schema

users

column name	data type	details
id	integer	not null, primary key
username	string	not null, indexed, unique
email	string	not null, indexed, unique
password_digest	string	not null
session_token	string	not null, indexed, unique
created_at	datetime	not null
updated_at	datetime	not null

• index on username, unique: true
• index on email, unique: true
• index on session_token, unique: true
• has_many posts
• has_many follows

posts

column name	data type	details
id	integer	not null, primary key
pet_name	string	not null
pet_gender	string	not null
pet_breed	string	not null
pet_age	integer	not null
author_id	integer	not null, indexed, foreign key
created_at	datetime	not null
updated_at	datetime	not null

• author_id references users
• index on author_id
• belongs_to author

follows

column name	data type	details
id	integer	not null, primary key
user_id	integer	not null, indexed, foreign key
post_id	integer	not null, indexed, foreign key
created_at	datetime	not null
updated_at	datetime	not null

• user_id references users
• post_id references posts
• index on [:post_id, :user_id], unique: true
• belongs_to user
• belongs_to post

messages

column name	data type	details
id	integer	not null, primary key
body	string	not null
user_id	integer	not null, indexed, foreign key
receiver_id	integer	not null, indexed, foreign key
created_at	datetime	not null
updated_at	datetime	not null

• user_id references user
• receiver_id references user
• index on [:post_id, :user_id], unique: true
• belongs_to user
• belongs_to user

// We don't need a separate index for post_id or user_id because the first index adds it for us.