MySQL 创建用户表和好友表

人生如果错了方向，停止就是进步

最近想做一个即时通讯的Android demo，但是一直不知道如何处理用户和好友之间的表关系。在网上找了好久也没找到合适的。我本人很少接触数据库，对数据库语句比较差。

但是这只是自己demo，只能自己写。

创建数据库

好了，不多逼逼，现在开始创建一个数据库吧。

create database my_chat;

这一步相信大家都很明白，就是创建了一个my_chat的数据库

创建表

选择数据库

use my_chat;

创建用户表

create table userTable
(
    userId int auto_increment primary key,  --用户ID自增
    password varchar(100),    --密码
    userName varchar(100) unique, --用户名
    birthYear smallint,  --出生年
    birthMonth smallint, --出生月
    birthDay smallint,   --出生日
    gender smallint,  -- 0 为女性, 1 为男 
    avatarId int,  --头像Id
    isOnline int,  -- 0 为离线, 1 在线
    signupTime varchar(100),  -- XXXX-XX-XX-XX-XX (year-month-day-hour-minute)注册日期
    hometown varchar(100), -- 家乡
    location varchar(100) -- 现居住地
);    

添加用户表信息

insert into userTable(password,userName,birthYear,birthMonth,birthDay,gender,avatarId,isOnline,signupTime,hometown,location) 
values("123456","test1",1997,09,23,1,0,1,"2020-09-23","广西/百色","广东珠海");

insert into userTable(password,userName,birthYear,birthMonth,birthDay,gender,avatarId,isOnline,signupTime,hometown,location) 
values("123456","test2",1998,03,26,0,1,1,"2020-09-23","广西/百色","广东珠海");

创建好友表

create table friendListTable
(
    masterId int, -- 此好友列表所属用户的id
    friendId int, --好友Id
    friendName varchar(100),  --好友姓名
    friendBirthYear smallint,  --好友出生年
    friendBirthMonth smallint,  --好友出生月
    friendBirthDay smallint,   --好友出生日
    friendGender smallint,  --好友友性别
    friendAvatarId int,   --好友头像
    friendIsOnline int,   -- 好友在线状态
    friendSignupTime varchar(100),  --好友注册日期
    friendHometown varchar(100),   -- 好友家乡
    friendLocation varchar(100),  --好友现居住地
    foreign key(masterId) references userTable(userId) on delete cascade  --当用户信息修改或删除，该表同步修改
);

添加好友数据

insert into friendListTable(masterId,friendId,friendName,friendBirthYear,friendBirthMonth,friendBirthDay,friendGender,friendAvatarId,friendIsOnline,friendSignupTime,friendHometown,friendLocation) 
values(1,2,"test2",1998,03,26,0,1,1,"2020-09-23","广西/百色","广东珠海");

insert into friendListTable(masterId,friendId,friendName,friendBirthYear,friendBirthMonth,friendBirthDay,friendGender,friendAvatarId,friendIsOnline,friendSignupTime,friendHometown,friendLocation) 
values(2,1,"test1",1997,09,23,0,0,1,"2020-09-23","广西/百色","广东珠海");

获取所有好友

select * from friendListTable where masterId=2;

获取所有在线好友

select * from friendListTable where masterId=2 and friendIsOnline=1;

获取所有离线好友

select * from friendListTable where masterId=? and friendIsOnline=0;

创建消息表

create table unSendMsgs
(
    senderId int,
    receiverId int,
    msg text,
    _datetime datetime,
    type int
)

添加消息数据

insert into unSendMsgs (senderId,receiverId,msg,_datetime,type) values(1,2,"这是n一条测试消息",now(),1);
insert into unSendMsgs (senderId,receiverId,msg,_datetime,type) values(2,1,"收到",now(),0);
 insert into unSendMsgs (senderId,receiverId,msg,_datetime,type) values(1,3,"四号是个大撒比",now(),0);
insert into unSendMsgs (senderId,receiverId,msg,_datetime,type) values(3,1,"三号明白",now(),1);
insert into unSendMsgs (senderId,receiverId,msg,_datetime,type) values(1,3,"over over",now(),0);

查询一号和三号互相发送的消息

 select * from unSendMsgs where senderId=1 and receiverId=3 or senderId=3 and receiverId=1 order by _datetime asc;

结果如下

+----------+------------+-----------------------+---------------------+------+
| senderId | receiverId | msg                   | _datetime           | type |
+----------+------------+-----------------------+---------------------+------+
|        1 |          3 | 四号是个大撒比          | 2020-09-20 12:01:14 |    0 |
|        3 |          1 | 三号明白               | 2020-09-20 12:01:36 |    1 |
|        1 |          3 | over over             | 2020-09-20 12:01:51 |    0 |
+----------+------------+-----------------------+---------------------+------+

好了，关于用户表和好友表哦以及消息表的关系就如上，日后可能会继续更新，从0搭建即时通讯demo，喜欢的可以点个赞