[大数据]MySQL建表

-- 文章相关信息表
CREATE TABLE authors (    -- 作者户信息
	uid INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
	username VARCHAR(45) NOT NULL UNIQUE
);
CREATE TABLE articles(     -- 文章信息
    aid INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
    uid INT  NOT NULL,
    title VARCHAR(200) NOT NULL,
    body TEXT NOT NULL,
    published_at DATETIME NOT NULL
);
-- 借书相关表
CREATE TABLE books(
    bid INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
    name VARCHAR(20) NOT NULL,
    total_count INT NOT NULL,
    current_count INT NOT NULL
);
CREATE TABLE users(
     uid INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
     username VARCHAR(45) NOT NULL UNIQUE
);
CREATE TABLE borrow_records(
     brid INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
     uid INT NOT NULL COMMENT '谁的书',
     bid INT NOT NULL COMMENT '借了什么书',
     borrowed_at DATETIME NOT NULL COMMENT '何时借的书'
);