CODEWITHSUNDEEP
database-designerd
anon anon
anon anon

Reputation: 161

Entity relational Diagram for Facebook

I am curious to know how a Entity relational Diagram would look for Facebook. I am a bit confused because there is an overlap between friends and a user, which causes duplicate data entries in the database.

A user can make a post, and can have many friends

however,

A friend can also make a post and have friends of their own

How would you design a schema for a social media application such as facebook?

Thank you!

Upvotes: 1

Views: 2914

Answers (2)

Gholamali Irani
Gholamali Irani

Reputation: 4350

A user can creates many post.
A user can have many friends. First, this relationship is a many-to-many relationship on user. Then we can map it as a new entity and named it friends with two F.K from user. For example it can save that user1 and user2 are friends.

A friend is a user too. So he/she (as a user) can creates posts too.

The ER in UML notation can be like below:

enter image description here

Note that, this ER shows that user1 is a friend to user2 (not vise versa). But from meaning of friendship, we can result that user2 is friend of user1 too.

Additionally, Friends relationship is a graph relationship between users. In ordinary projects above ER is good. But in big and real projects you can use Graph Databases like neo4j.

Upvotes: 1

LJ01
LJ01

Reputation: 589

I would imagine something a little like;

    User table - user details
    Post table - owned by a user
    Friends table - a table that stores the link between people.

Upvotes: 1

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