System-Design-Splitwise

This repository contains a simplified version of Splitwise system, an easy to split bills with friends and family.

Design Splitwise

Requirements :

• Users can register and update their profiles.
• A user's profile should contain at least their name, phone number and password
• Users can participate in expenses with other users
• Users can participate in groups.
• To add an expense, a user must specify either the group, or the other users involved in the expense, along with who paid what and who owes what. They must also specify a description for the expense.
• A user can see their total owed amount
• A user can see a history of the expenses they're involved in
• A user can see a history of the expenses made in a group that they're participating in
• Users shouldn't be able to query about groups they are not a member of
• Only the user who has created a group can add/remove members to the group
• Users can request a settle-up. The application should show a list of transactions, which when executed will ensure that the user no longer owes or recieves money from any other user. Note that this need not settle-up any other users.
• Users can request a settle-up for any group they're participating in. The application should show a list of transactions, which if executed, will ensure that everyone participating in the group is settled up (owes a net of 0 Rs). Note that will only deal with the expenses made inside that group. Expenses outside the group need not be settled.
• When settling a group, we should try to minimize the number of transactions that the group members should make to settle up.

Class Diagram :

User

• name
• username
• email
• password

Expense

• description
• amount
• currency
• createdAt
• Participants
• paidBy
• paidFor
• Group

Group

• name
• Members
• Admins
• CreatedBy

Schema Diagram :

User - USERS

• id
• name
• username
• email
• password

Expense - EXPENSES

• id - PK
• description - VARCHAR(255)
• amount - DOUBLE
• currency - VARCHAR(3)
• createdAt - DATETIME
• groupId - FK

Group - GROUPS

• id - PK
• name - VARCHAR(255)
• createdBy - FK
• createdAt - DATETIME

Mapping - GROUP_MEMBERS

• groupId - FK
• userId - FK

Mapping - GROUP_ADMINS

• groupId - FK
• userId - FK

Mapping - EXPENSE_PARTICIPANTS

• expenseId - FK
• userId - FK

Technologies Used

• Spring Boot: For creating stand-alone, production-grade Spring-based applications.
• Java: As the main programming language.
• Model-View-Controller (MVC): For separating the application's concerns.