Lecture 384:- Schema Setup - Likes

To set up the schema for likes, we need to consider the following:

1. A like can belong to either a post or a comment.
2. A like is associated with a user who created it.
3. A user can like a post or a comment only once.
4. The count of likes needs to be stored with the post or comment to avoid extra computation.

With the above considerations, we can set up the schema for likes as follows:

likes table:

• id (primary key)
• likeable_id (integer, foreign key)
• likeable_type (string)
• user_id (integer, foreign key)
• created_at (timestamp)

Here, the likeable_id and likeable_type are used to define a polymorphic relationship with either the posts or comments table.

posts table:

• id (primary key)
• title (string)
• content (text)
• user_id (integer, foreign key)
• likes_count (integer)

comments table:

• id (primary key)
• content (text)
• post_id (integer, foreign key)
• user_id (integer, foreign key)
• likes_count (integer)

Here, we have added the likes_count column to the posts and comments tables to keep track of the total number of likes for a post or a comment.

With the above schema, we can create a new like by inserting a record into the likes table with the likeable_id, likeable_type, and user_id. We can then increment the likes_count for the corresponding post or comment. We can also check if a user has already liked a post or a comment by querying the likes table for a record with the given likeable_id, likeable_type, and user_id.