Creating Groups

[Bbowen100]

If one person pays the group bill

• A transaction will be created between each member of the group and the person who pays

Transactions in a group will be represented as a graph

• If a cycle exists in the graph then a normalized value should appear for all the members in the cycle
• Have a group-transaction model that has a 1:n relationship with the transaction model.
• Have a group-friendship model that tracks balance and such.

[RSNara]

Is there any update on this enhancement?

[MaazAli]

Models

GroupTransactions

A transaction that can occur between more than two people. Multiple people may pay for it, and multiple people may owe these people money. A group transaction can create multiple GroupSingularTransactions.

GroupSingularTransactions

Act very similar to the normal transactions model, but in the context of a group.

The reason we don't want to re-use the transactions model:

• it directly updates the "friendship" balance but will not be able to update the GroupFriendships balance, which we also need to keep track of.
• there are cases where people in groups may not actually have "Friendships" and thus a transaction created inside a group would try to update the friendship balance, which would not exist.
• a transaction must be related to GroupTransactions as well as GroupFriendships. Currently no fields exist to do that, although relatedGroupObject field can work for GroupFriendships, we won't have a field for the GroupTransactions.

GroupFriendships

Essentially a normal friendship, but in the context of a group. Two users can have a GroupFriendship while not having a normal Friendship (may not be friends on facebook). Additionally, each user in the group has N - 1 GroupFriendships each, where N is the number of people in the group. Hence, there are N^2 GroupFriendships per Group. A GroupFriendship will try to link to a Friendship, if the users have one. This will allow GroupSingularTransactions to update the balance of Friendships as well.

Note: We will need to figure out how to update this record, if a Friendship is born later on down the line.

GroupFriendshipData

Since a relation in a group is duplicated (Jack and Jill will each have their own GroupFriendship of each other, hence 2 for each relation). To reduce duplication of data we have a GroupFriendshipData, this holds the relationship's balance in the group, etc.

Groups

Has many GroupFriendships and GroupTransactions. The creator of the group can also turn on Simplify Transactions option which will normalize transactions between users of a group.

• "If a cycle exists in the graph then a normalized value should appear for all the members in the cycle" ~ @Bbowen100