Database Schema

all tables

• users
• permissions (joins)
• channels
• memberships (joins)
• direct_messages

users

Column Name	Data Type	Details
id	integer	not null, primary key
email	string	not null, indexed, unique
display_name	string	not null
password_digest	string	not null
session_token	string	not null, indexed, unique

• index on email, unique: true
• index on session_token, unique: true
• AWS will host profile pictures, so img_url unnecessary

permissions (joins)

Column Name	Data Type	Details
id	integer	not null, primary key
user_id	integer	not null
channel_id	integer	not null

• user_id references users (belongs_to :user)
• channel_id references channels (belongs_to :channel)
• index on :channel_id
• index on [:user_id, :channel_id], unique: true

channels

Column Name	Data Type	Details
id	integer	not null, primary key
title	string	not null
private	boolean	not null
is_dm	boolean	not null

• has_many :permissions
• has_many :permitted_users, through: permissions, source: user
• has_many :messages, as: :messageable

messages

Column Name	Data Type	Details
id	integer	not null, primary key
body	text	not null
author_id	integer	not null, indexed, foreign key
messageable_type	string	not null
messageable_id	integer	not null, foreign key

• author_id references users (belongs_to :user)
• belongs_to messageable, polymorphic: true
  • messageable_type is "channel"
  • messageable_id references a channel

included in all tables

Column Name	Data Type	Details
created_at	datetime	not null
updated_at	datetime	not null