ssm+restful bbs后台设计
数据库设计： CREATE TABLE user ( user_id int(11) NOT NULL AUTO_INCREMENT, user_name varchar(50) DEFAULT NULL, email varchar(50) DEFAULT NULL, replys int(11) DEFAULT NULL, topics int(11) DEFAULT NULL, create_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, praises int(11) DEFAULT NULL, PRIMARY KEY (user_id) ）
CREATE TABLE post (
topic_id int(11) NOT NULL AUTO_INCREMENT,
user_id int(11) NOT NULL,
title varchar(100) NOT NULL,
content` varchar(20140) NOT NULL,
create_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
lastset_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON
UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (topic_id),
FOREIGN KEY (use_id) REFERENCES user (user_id)
)
CREATE TABLE comment ( comment_id int(11) NOT NULL AUTO_INCREMENT, topic_id int(11) NOT NULL, user_id int(11) NOT NULL, comment_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, content varchar(200) NOT NULL, PRIMARY KEY (comment_id), FOREIGN KEY (use_id) REFERENCES user (user_id), FOREIGN KEY (topic_id) REFERENCES post(topic_id) )
CREATE TABLE reply ( reply_id int(11) NOT NULL AUTO_INCREMENT, comment_id int(11) NOT NULL, reply_user int(11) NOT NULL, reply_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, content varchar(200) NOT NULL, PRIMARY KEY (reply_id), FOREIGN KEY (comment_id) REFERENCES comment (comment_id) FOREIGN KEY (reply_user) REFERENCES user (user_id) )
CREATE TABLE praise (
id int(11) NOT NULL AUTO_INCREMENT,
topic_id int(11) NOT NULL,
user_id int(11) NOT NULL,
PRIMARY KEY (id),
FOREIGN KEY (use_id) REFERENCES user (user_id)
FOREIGN KEY (topic_id) REFERENCES post (topic_id)
)
设计时在reply（回复表）和comment（评论表）的逻辑花不少时间，考虑的是前台每个帖子详情下面，用户可以对帖主评论，而在每个评论下面其他用户可以对该评论回复，就像贴吧的楼主一样。一般评论或回复都可以删除，在设计时产生了不少外码依赖（可能设计的有点水/汗颜），如果删除帖子或者评论，建立联级删除后原来关联的评论回复记录都没有，但这并不是我们想要的，所以就加了外码的SET NULL依赖，只是把外码设置成null就行。
comment : alter table comment add constraint comment_cons foreign key(topic_id) references post(topic_id) on delete set null;
reply: alter table reply add constraint reply_cons foreign key(comment_id) references comment(comment_id) on delete set null;
praise: alter table praise add contraint praise_cons foreign key(topic_id) references post(topic_id) on delete set null;