|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
说明:此文件包括了blog数据库中建立全部的表的Mysql语句.在sql语句中注意“约束的概念":1.实体完整性约束(主键--唯一且非空) primary key()
违约处理:No action(拒绝运行)
2.參照完整性约束(外键约束)foregin key() references tableName(filedName) [on delete|update casecade | no action]
违约处理:级联更新或拒绝运行
3.用户自己定义完整性约束(not null,unique,check短语)
违约处理:拒绝运行
//增加列语法//【alter table blog_article add columName type constraint】
//增加约束样例//【alter table blog_article add CONSTRAINT foreign key(category_Name) references blog_category(category_Name) on delete cascade on update cascade】
问题:怎样让相冊，相片，文章公用一个评论表?create database blog;
create table blog_user
( user_Name char(15) not null check(user_Name !=\'\'),
user_Password char(15) not null,
user_emial varchar(20) not null unique,
primary key(user_Name)
)engine=innodb default charset=utf8 auto_increment=1;
create table blog_category
( category_Name char(18) not null check(category_Name!=\'\'),
category_Date datetime not null,
primary key(category_Name)
)engine=innod default charset=utf8 auto_increment=1;
create table blog_article
( article_Id int unsigned not null auto_increment,
article_title varchar(20) not null unique,
article_content longtext not null,
article_date datetime not null,
article_readTime int unsigned not null default 0,
user_Name char(15) not null,
category_Name char(18) not null,
primary key(article_Id),
foreign key(user_Name) references blog_user(user_Name) on delete cascade on update cascade,
foreign key(category_Name) references blog_category(category_Name) on delete cascade on update cascade
)engine=innodb default charset=utf8 auto_increment=1;
CREATE TABLE blog_comment (
comment_Id int(10) unsigned NOT NULL AUTO_INCREMENT,
comment_Content varchar(90) NOT NULL,
comment_Date datetime NOT NULL,
article_Id int(10) unsigned NOT NULL,
user_Name char(15) NOT NULL,
PRIMARY KEY (comment_Id),
foreign key(article_Id) references blog_article(article_Id) on delete cascade on update cascade,
foreign key(user_Name) references blog_user(user_Name) on delete cascade on update cascade
)engine=innodb default charset=utf8 auto_increment=1;
create table blog_photoAlbum
( photoAlbum_Name char(20) not null check(photoAlbum_Name!=\'\'),
photoAlbum_Date datetime not null,
primary key(photoAlbum_Name)
)engine=innodb default charset=utf8;
create table blog_photograph
( photograph_Name varchar(20) not null check(photograph_Name!=\'\'),
photograph_Date datetime not null,
photoAlbum_Name char(20) not null,
photoURL varchar(90) not null,
foreign key(photoAlbum_Name) references blog_photoAlbum(photoAlbum_Name) on delete cascade on update cascade
)engine=innodb default charset=utf8;
|
相关文章：