diff --git a/migrations/003_slug_partial_unique.sql b/migrations/003_slug_partial_unique.sql
new file mode 100644
index 0000000..9b6d5d7
--- /dev/null
+++ b/migrations/003_slug_partial_unique.sql
@@ -0,0 +1,5 @@
+-- 删除全局唯一约束
+ALTER TABLE posts DROP CONSTRAINT IF EXISTS posts_slug_unique;
+
+-- 创建部分唯一索引（仅对未删除记录）
+CREATE UNIQUE INDEX idx_posts_slug_unique ON posts(slug) WHERE deleted_at IS NULL;