Schema

users

Column Name	Data Type	Details
id	integer	not null, primary key
email	string	not null, unique, indexed
name	string	not null
password_digest	string	not null
session_token	string	not null, indexed
created_at	datetime	not null
updated_at	datetime	not null

bills

Column Name	Data Type	Details
id	integer	not null, primary key
author_id	integer	not null, foreign key
history_id	integer	not null, foreign key
group_id	integer	foreign key
cost	decimal	not null
description	text	not null
created_at	datetime	not null
updated_at	datetime	not null

• author_id references users
• history_id references transaction history
• group_id references groups

comments

Column Name	Data Type	Details
id	integer	not null, primary key
author_id	integer	not null, foreign key
bill_id	integer	not null, foreign key
text_body	text	not null
created_at	datetime	not null
updated_at	datetime	not null

• author_id references users
• bill_id references bills

history

Column Name	Data Type	Details
id	integer	not null, primary key
author_id	integer	not null, foreign key
created_at	datetime	not null
updated_at	datetime	not null

friends

Column Name	Data Type	Details
id	integer	not null, primary key
author_id	integer	not null, foreign key
friend_id	integer	not null, foreign key
created_at	datetime	not null
updated_at	datetime	not null

• author_id references users that initiated friends listing
• friend_id references users that accepted friends listing

memberships

Column Name	Data Type	Details
id	integer	not null, primary key
user_id	integer	not null, foreign key
group_id	integer	not null, foreign key
created_at	datetime	not null
updated_at	datetime	not null

• user_id references users
• group_id references groups

transactions

Column Name	Data Type	Details
id	integer	not null, primary key
bill_id	integer	not null, foreign key
user_id	integer	foreign key
created_at	datetime	not null
updated_at	datetime	not null

• bill_id references bills
• user_id references users who received either a credited or debited expense

groups

Column Name	Data Type	Details
id	integer	not null, primary key
author_id	integer	not null, foreign key
title	integer	not null
created_at	datetime	not null
updated_at	datetime	not null

• author_id references users that created group