CREATE TABLE post_likes (
                            post_id BIGINT NOT NULL,
                            user_id BIGINT NOT NULL,
                            created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),

    -- 复合主键，防止重复点赞
                            PRIMARY KEY (post_id, user_id)
);

-- [核心索引] 优化 "feed流中判断我是否已赞" (user_id = ? AND post_id IN (...))
CREATE INDEX idx_post_likes_lookup ON post_likes(user_id, post_id);

-- [核心索引] 优化 "我赞过的帖子" 列表
CREATE INDEX idx_post_likes_user_timeline ON post_likes(user_id, created_at DESC);