Project Specification

This document describes the functional and non$-$functional requirements of

Message Hub, a mobile instant messaging application. Message Hub is designed

to leverage the contacts on a user's mobile device to facilitate text messaging

services, supporting a variety of message types, including text, audio, video, and

documents $($PDF$,$ WORD, etc.$).$

Requirements:

User Management: Users have the ability to import contacts, send

messages individually or in groups, and join or create up to $100$ groups.

Each user is identified by a unique ID$,$ and their personal information such

as phone number, name, bio, email, profile pictures, location, and

availability status. Users may also choose a unique username for contact

purposes without disclosing their phone number or ID$.$

Group and Channel Dynamics: Groups, with a capacity of up to $2000$

members, allow for message pinning and general participation. Channels,

designed for larger audiences, limit posting privileges to creators and

admins but offer unlimited membership. Each message within a channel

features a view counter and maintains the channel's identity. Both group

types support multiple message formats.

Account Management: Users can permanently delete their accounts,

which eradicates all personal messages and contacts. However, any groups

or channels initiated by the user will remain accessible to their designated

administrators.

Interaction and Notification Controls: MessageHub enables users to

interact with messages, track conversation threads, and manage unread

message counts across chat types. Additionally, users can tailor

notification settings for private chats, groups, and channels.

Message Editing and Deletion: Post$-$publication, users retain the ability

to edit or completely remove messages. Deleting a message will delete it

for everyone.

Administrative Functions: Group creators can assign administrative

roles, offering varying levels of group management capabilities. Unique

usernames and join links facilitate easy group access.

Server$-$Side Architecture: The application operates without a local

database, relying on server$-$side storage for all data transactions.

Tasks:

You must complete all of the following steps:

Develop an ER model detailing entity sets, relationship sets, keys, and

constraints. Explain any necessary constraints that your ER diagram cannot

model. Draw the diagram using chen notation please.$(15$ pts$)$

Based on the ER model, design a relational schema for the database. $(10$

pts$)$