Explaining the differences between .references() and relations function

...
 
export const posts = pgTable('posts', {
    id: serial('id').primaryKey(),
    content: text('content'),
    authorId: integer('author_id'),
});
 
export const postsRelations = relations(posts, ({ one, many }) => ({
    author: one(users, {
        fields: [posts.authorId],
        references: [users.id],
    }),
    comments: many(comments)
}));
 
export const comments = pgTable('comments', {
    id: serial('id').primaryKey(),
    text: text('text'),
    authorId: integer('author_id'),
    postId: integer('post_id'),
});
 
export const commentsRelations = relations(comments, ({ one }) => ({
    post: one(posts, {
        fields: [comments.postId],
        references: [posts.id],
    }),
}));