数据库常规操作【不定期更新】

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记录一些数据库常用的操作，以备不时之需

先把一个练习的SQL贴上来，包括使用TIMESTAMP类型、创建UNIQUE约束、创建外键约束，设置数据库引擎和设置字符集

CREATE DATABASE teacher;
use teacher;

DROP TABLE IF EXISTS t_root;
CREATE TABLE t_root (
    id int(11) NOT NULL AUTO_INCREMENT,
    admin_name varchar(255) NOT NULL,
    admin_password VARCHAR(255) NOT NULL,
    create_time TIMESTAMP NOT NULL default current_timestamp comment '创建时间',
    update_time timestamp not null default current_timestamp on update current_timestamp comment '修改时间',
    PRIMARY KEY (id),
    UNIQUE KEY UK_NAME (admin_name)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

INSERT INTO t_root (admin_name, admin_password) VALUE ("root", "123456");

DROP TABLE IF EXISTS t_user;
CREATE TABLE t_user (
    id INT(11) NOT NULL AUTO_INCREMENT,
    user_name VARCHAR(255) NOT NULL,
    user_pwd VARCHAR(255) NOT NULL,
    user_nickname VARCHAR(255) NOT NULL,
    user_images VARCHAR(255) DEFAULT NULL COMMENT "头像",
    user_birthday TIMESTAMP NOT NULL,
    user_type INT(10) NOT NULL,
    user_title VARCHAR(255) DEFAULT "助教" COMMENT "职称",
    create_time TIMESTAMP NOT NULL default current_timestamp comment '创建时间',
    update_time timestamp not null default current_timestamp on update current_timestamp comment '修改时间',
    PRIMARY KEY (id),
    UNIQUE KEY UK_NAME (user_name)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS t_lesson;
CREATE TABLE t_lesson (
    id INT(11) NOT NULL AUTO_INCREMENT,
    lesson_name VARCHAR(255) NOT NULL,
    lesson_describe TEXT DEFAULT NULL,
    lesson_image VARCHAR(255) DEFAULT NULL,
    lesson_class_hour INT DEFAULT 0 COMMENT "课时",
    create_time TIMESTAMP NOT NULL default current_timestamp comment '创建时间',
    update_time timestamp not null default current_timestamp on update current_timestamp comment '修改时间',
    PRIMARY KEY (id),
    UNIQUE KEY UK_NAME (lesson_name)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS t_select_lesson;
CREATE TABLE t_select_lesson (
    id INT(11) NOT NULL AUTO_INCREMENT,
    user_id INT(11) NOT NULL,
    lesson_id INT(11) NOT NULL,
    lesson_hour int DEFAULT 0 COMMENT "已修课时",
    PRIMARY KEY (id),
    CONSTRAINT fk_uid FOREIGN KEY (user_id) REFERENCES t_user (id),
    CONSTRAINT fk_lid FOREIGN KEY (lesson_id) REFERENCES t_lesson(id)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS t_bbs;
CREATE TABLE t_bbs (
    id INT(11) NOT NULL AUTO_INCREMENT,
    bbs_title VARCHAR(255) NOT NULL,
    bbs_content TEXT NOT NULL,
    bbs_author VARCHAR(255) NOT NULL,
    create_time TIMESTAMP NOT NULL default current_timestamp comment '创建时间',
    update_time timestamp not null default current_timestamp on update current_timestamp comment '修改时间',
    PRIMARY KEY (id)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS t_news;
CREATE TABLE t_news (
    id INT(11) NOT NULL AUTO_INCREMENT,
    news_title VARCHAR(255) NOT NULL,
    news_content TEXT NOT NULL,
    news_author VARCHAR(255) NOT NULL,
    create_time TIMESTAMP NOT NULL default current_timestamp comment '创建时间',
    update_time timestamp not null default current_timestamp on update current_timestamp comment '修改时间',
    PRIMARY KEY (id)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;