feat: 更新数据库架构，增加分类表及相关约束

schema.sql

@@ -1,7 +1,8 @@
-DROP TABLE IF EXISTS posts;
-DROP TABLE IF EXISTS users;
-DROP TABLE IF EXISTS tags;
 DROP TABLE IF EXISTS post_tags;
+DROP TABLE IF EXISTS posts;
+DROP TABLE IF EXISTS tags;
+DROP TABLE IF EXISTS categories;
+DROP TABLE IF EXISTS users;
 
 CREATE TABLE users (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
@@ -10,6 +11,12 @@ CREATE TABLE users (
   created_at DATETIME DEFAULT CURRENT_TIMESTAMP
 );
 
+CREATE TABLE categories (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  name TEXT NOT NULL UNIQUE,
+  slug TEXT NOT NULL UNIQUE
+);
+
 CREATE TABLE posts (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   slug TEXT NOT NULL UNIQUE,
@@ -17,9 +24,11 @@ CREATE TABLE posts (
   excerpt TEXT,
   content TEXT NOT NULL,
   author_id INTEGER NOT NULL,
+  category_id INTEGER,
   published_at DATETIME DEFAULT CURRENT_TIMESTAMP,
   updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
-  FOREIGN KEY (author_id) REFERENCES users(id)
+  FOREIGN KEY (author_id) REFERENCES users(id),
+  FOREIGN KEY (category_id) REFERENCES categories(id) ON DELETE SET NULL
 );
 
 CREATE TABLE tags (
@@ -35,18 +44,21 @@ CREATE TABLE post_tags (
   FOREIGN KEY (tag_id) REFERENCES tags(id) ON DELETE CASCADE
 );
 
--- Insert a default user (password should be hashed in a real scenario, this is a placeholder)
+-- Insert a default user
 INSERT INTO users (username, password_hash) VALUES ('admin', 'admin');
 
--- Insert some dummy posts
-INSERT INTO posts (slug, title, excerpt, content, author_id) VALUES 
+-- Insert default categories
+INSERT INTO categories (name, slug) VALUES ('默认分类', 'uncategorized'), ('技术分享', 'tech'), ('生活随笔', 'life');
+
+-- Insert dummy posts
+INSERT INTO posts (slug, title, excerpt, content, author_id, category_id) VALUES 
 ('hello-world', 'Hello, BlogFlare!', 'This is my first post on BlogFlare.', 'Welcome to my new blog powered by **SvelteKit** and **Cloudflare D1**.
 
 > [!NOTE]
 > This is a DoIt style admonition!
 
-It is incredibly fast and cheap to host.', 1),
-('void-theme', 'The Beauty of VOID', 'Typography is essential.', 'Typecho Theme VOID inspired this design. It uses a very clean layout.', 1);
+It is incredibly fast and cheap to host.', 1, 2),
+('void-theme', 'The Beauty of VOID', 'Typography is essential.', 'Typecho Theme VOID inspired this design. It uses a very clean layout.', 1, 2);
 
 INSERT INTO tags (name) VALUES ('Welcome'), ('Design');
 INSERT INTO post_tags (post_id, tag_id) VALUES (1, 1), (2, 2);