Instagram (Study Case)

This ERD represents a simplified Instagram-style social media platform database structure. The schema supports core social networking features including user accounts, posts, comments, likes, hashtags, stories, saved posts, and direct messaging. The `users` table stores account information, profile data, privacy settings, and authentication-related fields. User relationships are managed through the `follows` table, which enables follower and following connections between users. User-generated content is stored in the `posts` table. Each post can contain multiple images through the `post_images` table. Posts also support tagged locations and text captions. The interaction system includes comments and likes. The `comments` table supports nested replies using a self-referencing parent comment structure. Post and comment reactions are handled through the `post_likes` and `comment_likes` tables. Hashtag functionality is implemented using a many-to-many relationship between `posts` and `hashtags` through the `post_hashtags` mapping table. The schema also includes Instagram-style stories using the `stories` and `story_views` tables. Stories contain temporary content with expiration timestamps and user view tracking. For private communication, the ERD includes a direct messaging system composed of `direct_message_rooms`, `direct_message_room_members`, and `direct_messages`. This structure supports multi-user chat rooms and message history management. This ERD is intended for database modeling examples, ERD visualization, social media clone projects, and relational database design practice.