Entity-Relationship Diagram (ERD) for a Social Application

?? Designing the ERD for a Social Application: A Detailed Breakdown

In this article, we explore the Entity-Relationship Diagram (ERD) for a simplified social application model. The core entities we focus on include User Profile, User Post, Post Like, and Post Comment. These entities reflect the basic interactions users engage in, such as creating profiles, posting content, liking posts, and commenting on them.

Let's dive into the specifics of each entity and its relationships!

1. ?? User Profile

Attributes:

• UserID (PK): Unique identifier for each user.
• Username: The name displayed on the user’s profile.
• Email: The user’s email address for identification and communication.
• Password: A secure credential for user authentication.
• ProfilePicture: The image representing the user’s profile.
• Bio: A brief description provided by the user.
• DateOfBirth: The user's date of birth.
• DateJoined: The date when the user joined the platform.

Description: The User Profile entity is central to the social application, representing individual users. The UserID is the primary key used to identify and link users with other entities such as posts, comments, and likes.

2. ?? User Post

Attributes:

• PostID (PK): Unique identifier for each post.
• UserID (FK): Foreign Key referencing the UserID in the User Profile entity.
• Content: The main text or media content of the post.
• MediaURL: A URL link to any image, video, or media content included in the post.
• DateCreated: The date and time the post was published.
• PostType: Specifies whether the post contains text, image, or video content.
• Privacy: Indicates if the post is Public or Private.

Description: The User Post entity tracks the posts made by users. Every post is tied to a user through the UserID. A user can create multiple posts, forming a one-to-many (1

) relationship between User Profile and User Post. Posts may contain text, images, or videos, depending on the PostType.

3. ?? Post Like

Attributes:

• LikeID (PK): Unique identifier for each like.
• UserID (FK): Foreign Key referencing the UserID in the User Profile entity.
• PostID (FK): Foreign Key referencing the PostID in the User Post entity.
• DateLiked: The date and time the like was given.

Description: The Post Like entity captures interactions where users like posts. Each like is linked to both the user who liked the post and the post that was liked through Foreign Keys (UserID and PostID). This forms two one-to-many (1

) relationships:

1. User Profile ? Post Like: One user can like multiple posts.
2. User Post ? Post Like: One post can receive multiple likes.

4. ?? Post Comment

Attributes:

• CommentID (PK): Unique identifier for each comment.
• PostID (FK): Foreign Key referencing the PostID in the User Post entity.
• UserID (FK): Foreign Key referencing the UserID in the User Profile entity.
• Content: The text of the comment.
• DateCreated: The date and time the comment was posted.

Description: The Post Comment entity stores user comments on posts. A comment is connected to both the post it comments on and the user who created it, forming one-to-many (1

) relationships with both:

1. User Profile ? Post Comment: One user can comment on multiple posts.
2. User Post ? Post Comment: One post can receive multiple comments.

?? Key Relationships in the ERD

1. User Profile ? User Post (1
2. User Profile ? Post Like (1
3. User Profile ? Post Comment (1
4. User Post ? Post Like (1
5. User Post ? Post Comment (1

?? Summary

This ERD focuses on core interactions within a social application:

• User Profiles serve as the foundation.
• Users can create posts, and other users can like and comment on those posts.
• All interactions are built around one-to-many (1

These core entities capture the most essential features of a social media platform, providing a foundation for more complex features like messaging, group creation, and notifications.